Difference between revisions of "SH Lecture - Lymphatic Structure and Organs"

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==Introduction==
 
==Introduction==
[[File:SHsmall.jpg|left]] This lecture will provide an overview of the lymphoid structure and histology of key cells, vessels, structures and organs lymphoid organs, including the lymph nodes, spleen and thymus, as well as extranodal lymphoid tissues including mucosal associated lymphoid tissues (MALT).
+
[[File:SHsmall.jpg|left]]This lecture will provide an overview of the lymphoid structure and histology of key cells, vessels, structures and organs lymphoid organs, including the lymph nodes, spleen and thymus, as well as extranodal lymphoid tissues including mucosal associated lymphoid tissues (MALT).
  
 
In this lecture I will go through the structures in sequence from cells through to organs, immunity itself is covered in detail elsewhere in the course.
 
In this lecture I will go through the structures in sequence from cells through to organs, immunity itself is covered in detail elsewhere in the course.
 +
 +
 +
'''2019 Lecture''' - [[Media:2019 SH Lecture - Lymphatic Structure and Organs.pdf|'''Lecture PDF''']]
 +
<br>
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{| width="700px"
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! colspan=4|'''2019 Lecture Audio'''
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|-
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! width="100px"|Topic &nbsp;
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! width="300px"|Audio &nbsp;
 +
! width="120px"|Files &nbsp;
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! width="180px"|Size/Time &nbsp;
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|-
 +
| Lymphatics
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| <html5media>File:SH Lecture 180219 Lymphatics.mp3</html5media>
 +
| [[Media:SH Lecture 180219 Lymphatics.mp3‎|listen]] | [[:File:SH Lecture 180219 Lymphatics.mp3|download]]
 +
| 18.62 Mb MP3 51:14 min
 +
|-
 +
| colspan=4| Note live audio recordings may contain inaccuracies or errors. Refer always to the lecture notes below.
 +
|}
 +
<br>
 
{|
 
{|
|
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|  
 
{| class="wikitable mw-collapsible mw-collapsed"
 
{| class="wikitable mw-collapsible mw-collapsed"
! Textbook References
+
! Textbook References &nbsp;
 
|-  
 
|-  
 
| {{Embryo citation}}  
 
| {{Embryo citation}}  
* [[Media:SH Lecture 2014 - Lymphatic Structure and Organs.pdf|2014 Lecture PDF 22 pages, 2.8 Mb]]
+
* [[Media:2019 SH Lecture - Lymphatic Structure and Organs.pdf|PDF Lecture 2019]]
* [[SH_Practical_-_Lymphatic_Structure_and_Organs|SH Laboratory Support]] | [[Media:AIDS_related_lymphoma_movie.mp4|Movie - AIDS related lymphoma]] | [[Student:SH Lecture - Lymphatic Structure and Organs|Student Lecture Feedback]]
+
* [[SH_Practical_-_Lymphatic_Structure_and_Organs|SH Laboratory Support]] | [[Media:AIDS_related_lymphoma_movie.mp4|Movie - AIDS related lymphoma]] |  
 
* [[SH_Practical_-_Lymphatic_Quiz|Lymphatic Quiz]]
 
* [[SH_Practical_-_Lymphatic_Quiz|Lymphatic Quiz]]
 +
 +
[[File:Moodle icon2.jpg|left|40px]][http://moodle.telt.unsw.edu.au/mod/book/view.php?id=828270 '''Virtual Slides - Lymphatic''']: [http://moodle.telt.unsw.edu.au/mod/lti/view.php?id=794799 Human Blood Smear] | [http://moodle.telt.unsw.edu.au/mod/lti/view.php?id=802056 Bone Marrow Smear] | [http://moodle.telt.unsw.edu.au/mod/lti/view.php?id=804049 Thymus (infant)] | [http://moodle.telt.unsw.edu.au/mod/lti/view.php?id=794807 Thymus (adult 1)] |  [http://moodle.telt.unsw.edu.au/mod/lti/view.php?id=802962 Thymus (adult 2)] | [http://moodle.telt.unsw.edu.au/mod/lti/view.php?id=804048 Spleen] | [http://moodle.telt.unsw.edu.au/mod/lti/view.php?id=804648 Spleen (silver stain)] | [http://moodle.telt.unsw.edu.au/mod/lti/view.php?id=804046 Lymph Node] | [http://moodle.telt.unsw.edu.au/mod/lti/view.php?id=804042 Lymph Node  (silver stain)] |  [http://moodle.telt.unsw.edu.au/mod/lti/view.php?id=804051 Lingual tonsil (tongue}] | [http://moodle.telt.unsw.edu.au/mod/lti/view.php?id=804050 Pharyngeal tonsil] | [http://moodle.telt.unsw.edu.au/mod/lti/view.php?id=804637 Appendix] (slide access requires Zpass login)
 +
 
* Additional background information:
 
* Additional background information:
  
 
{{Immune Links}}
 
{{Immune Links}}
 
|-
 
|-
|  '''Janeway’s Immunobiology''' (see in [[SH_Lecture_-_Lymphatic_Structure_and_Organs#Additional_Information|additional information]]) [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=imm.TOC&depth=2 NCBI Bookshelf]  
+
|  '''Janeway’s Immunobiology''' (see in [[SH_Lecture_-_Lymphatic_Structure_and_Organs#Additional_Information|additional information]]) [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=imm.TOC&depth=2 NCBI Bookshelf] A good detailed textbook on the lymphatic system.
 
|-
 
|-
| '''Histology and Cell Biology''' - A.L. Kiersenbaum (2001) Chapter 6: Blood,  Chapter 10: Immune-Lymphatic
+
| '''Nature Immunology''' - These are short (5-10 min) animations showing how the immune system monitors the epithelial and environment interface at different anatomical locations.
 +
* [https://youtu.be/_VhcZTGv0CU Immunology of the skin]
 +
* [https://youtu.be/rgphaHmAC_A Immunology of the lung]
 +
* [https://youtu.be/gnZEge78_78 Immunology in the gut mucosa]
 +
 
 +
|-
 +
| [[File:Histology and cell biology, 3rd edn.jpg|left|90px|thumb]] Kierszenbaum, A. L., & Tres, L. L. (2012). ''Histology and cell biology: An introduction to pathology.'' Philadelphia, PA: Elsevier Saunders. UNSW Students have online access to the current 3rd edn. through the [https://ebookcentral-proquest-com.wwwproxy1.library.unsw.edu.au/lib/unsw/detail.action?docID=1430108 UNSW Library subscription].
 +
 
 +
 
 +
* [https://ebookcentral-proquest-com.wwwproxy1.library.unsw.edu.au/lib/unsw/reader.action?docID=1430108&ppg=186 Chapter 6. Blood And Hematopoiesis]
 +
* [https://ebookcentral-proquest-com.wwwproxy1.library.unsw.edu.au/lib/unsw/reader.action?docID=1430108&ppg=320 Chapter 10. Immune-Lymphatic System]
 +
** [https://ebookcentral-proquest-com.wwwproxy1.library.unsw.edu.au/lib/unsw/reader.action?docID=1430108&ppg=335 Lymph Node]
 +
** [https://ebookcentral-proquest-com.wwwproxy1.library.unsw.edu.au/lib/unsw/reader.action?docID=1430108&ppg=339 Thymus]
 +
** [https://ebookcentral-proquest-com.wwwproxy1.library.unsw.edu.au/lib/unsw/reader.action?docID=1430108&ppg=345 Spleen]
 +
* Chapter 16. Lower Digestive Segment [https://ebookcentral-proquest-com.wwwproxy1.library.unsw.edu.au/lib/unsw/reader.action?docID=1430108&ppg=501 Protection of the small intestine]
 +
* Blood Chapter Page 169 - Blood development information. Page 191 - Myeloid lineage histology.
 
|-
 
|-
 
|}
 
|}
|
+
|  
 +
{| class="wikitable mw-collapsible mw-collapsed"
 +
! Lecture Archive &nbsp;
 +
|-
 +
 +
[https://embryology.med.unsw.edu.au/embryology/index.php?title=SH_Lecture_-_Lymphatic_Structure_and_Organs&oldid=326414 2018] | [[Media:2018 SH Lecture - Lymphatic Structure and Organs.pdf|PDF 2018]] |
 +
[https://embryology.med.unsw.edu.au/embryology/index.php?title=SH_Lecture_-_Lymphatic_Structure_and_Organs&oldid=323348 2017] | [https://embryology.med.unsw.edu.au/embryology/index.php?title=SH_Lecture_-_Lymphatic_Structure_and_Organs&oldid=218091 2016]  | [[Media:SH Lecture 2016 - Lymphatic Structure and Organs.pdf|PDF 2016]] | [[Media:SH Lecture 2015 - Lymphatic Structure and Organs.pdf|PDF 2015]] | [https://embryology.med.unsw.edu.au/embryology/index.php?title=SH_Lecture_-_Lymphatic_Structure_and_Organs&oldid=175277 2015] | [[Media:SH Lecture 2014 - Lymphatic Structure and Organs.pdf|PDF 2014]] | [https://embryology.med.unsw.edu.au/embryology/index.php?title=SH_Lecture_-_Lymphatic_Structure_and_Organs&oldid=164891 2014] | [http://php.med.unsw.edu.au/embryology/index.php?title=SH_Lecture_-_Lymphatic_Structure_and_Organs&oldid=116560 2013] | [http://php.med.unsw.edu.au/embryology/index.php?title=SH_Lecture_-_Lymphatic_Structure_and_Organs&oldid=115513 2012] | [http://php.med.unsw.edu.au/cellbiology/index.php?title=2010_Society_and_Health_-_Lymphatic_organs_histology 2010]
 +
|}
 +
 
{| class="wikitable mw-collapsible mw-collapsed"
 
{| class="wikitable mw-collapsible mw-collapsed"
! Previous Lectures
+
! UNSW Research &nbsp;
 
|-
 
|-
| [[Media:SH Lecture 2014 - Lymphatic Structure and Organs.pdf|PDF 2014]] | [http://php.med.unsw.edu.au/embryology/index.php?title=SH_Lecture_-_Lymphatic_Structure_and_Organs&oldid=116560 2013] | [http://php.med.unsw.edu.au/embryology/index.php?title=SH_Lecture_-_Lymphatic_Structure_and_Organs&oldid=115513 2012] | [http://php.med.unsw.edu.au/cellbiology/index.php?title=2010_Society_and_Health_-_Lymphatic_organs_histology 2010] | [http://cellbiology.med.unsw.edu.au/units/medicine/SHlymph.htm 2008]
+
| valign=top|[[File:UNSWlogo2017.jpg|150px|link=https://med.unsw.edu.au]]
 +
| Some examples of UNSW research on immunity
 +
* [https://med.unsw.edu.au/infection-immunity-and-inflammation Infectious Disease, Immunity & Inflammation]
 +
* [https://kirby.unsw.edu.au/people/professor-anthony-kelleher Immunovirology and Pathogenesis Program]
 +
* [https://medicalsciences.med.unsw.edu.au/people/dr-rowena-bull evolution of RNA viruses]
 +
* [https://sms.unsw.edu.au/katharina-gaus How do T cells make decisions?]
 +
* [https://www.garvan.org.au/research/immunology/immunogenomics Garvan Immunogenomics]
 +
* [https://ccia.org.au/home/research-overview/improving-diagnosis/minimal-residual-disease-group/ Childrens Cancer Institute - Minimal Residual Disease]
 +
* [https://kirby.unsw.edu.au/projects Kirby Institute - Projects]
 
|}
 
|}
 
|}
 
|}
 
{|
 
{|
|-
+
|-bgcolor="F5FAFF"
 
! Structure
 
! Structure
 
! Function
 
! Function
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|  
 
|  
 
# '''Cells''' - blood cells (parenchyma), connective tissue (stroma)
 
# '''Cells''' - blood cells (parenchyma), connective tissue (stroma)
# '''Vessels''' - lymphatic vessels
+
# '''Vessels''' - lymphatic vessels, thin-walled, valves (NAVL)
 
# '''Diffuse''' - (extra-nodal tissue) nodules, Mucosal Associated Lymphoid Tissues (MALT)
 
# '''Diffuse''' - (extra-nodal tissue) nodules, Mucosal Associated Lymphoid Tissues (MALT)
 
# '''Nodes''' - (historic, "glands")
 
# '''Nodes''' - (historic, "glands")
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| valign="top"|
 
| valign="top"|
 
# '''Immune''' - “monitor” of body surfaces, internal fluids
 
# '''Immune''' - “monitor” of body surfaces, internal fluids
# '''Extracellular fluid''' - returns interstitial fluid to circulation
+
# '''Extracellular fluid''' - "returns" interstitial fluid to circulation
# '''Gastrointestinal tract''' - carries fat and fat-soluble vitamins
+
# '''Gastrointestinal tract''' - "carries" fat and fat-soluble vitamins (SI lacteals)
 
|}
 
|}
  
[[File:Lymphatic-system-overview.jpg|500px|Lymphatic system]]
+
[[File:Lymphatic-system-overview.jpg|600px|Lymphatic system]]
  
==Cells==
+
==Blood Cells==
  
[[File:Hematopoietic_and_stromal_cell_differentiation.jpg]]
+
{| class="wikitable mw-collapsible mw-collapsed"
 +
! Blood Cell Development  &nbsp;
 +
|-
 +
| [[File:Hematopoietic_and_stromal_cell_differentiation.jpg|600px]]
 +
|-
 +
| valign=top|Two Blood Cell Systems
  
 
Two Blood Cell Systems
 
 
# '''Mononuclear Phagocytic System''' - circulating monocytes of peripheral blood and non-circulating (fixed) tissue macrophages found throughout the body.
 
# '''Mononuclear Phagocytic System''' - circulating monocytes of peripheral blood and non-circulating (fixed) tissue macrophages found throughout the body.
 
# '''Lymphoid System''' - lymphocytes, three major types of T, B, and NK.
 
# '''Lymphoid System''' - lymphocytes, three major types of T, B, and NK.
Line 58: Line 115:
  
 
Lymphoid Organs
 
Lymphoid Organs
* Central  - Lymphocytes develop from precursor cells in bone marrow. (see blood marrow image)
+
* Central  - (primary) Lymphocytes develop from precursor cells in bone marrow and thymus. (see blood marrow image)
* Peripheral - Lymphocytes respond to antigen lymph nodes or spleen.
+
* Peripheral - (secondary) Lymphocytes respond to antigen lymph nodes or spleen.
 
 
  
 
{| class="wikitable mw-collapsible mw-collapsed"
 
{| class="wikitable mw-collapsible mw-collapsed"
! Blood Cells
+
! Blood Cells &nbsp;
 
|-  
 
|-  
 
| The blood cell information shown below in the table is shown to identify the relative proportions of different cell types in the circulating blood. This information is provided in the lecture as additional information for reference purposes only.
 
| The blood cell information shown below in the table is shown to identify the relative proportions of different cell types in the circulating blood. This information is provided in the lecture as additional information for reference purposes only.
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|}
 
|}
  
===1. Mononuclear Phagocytic System===
+
|}
  
Mononuclear Phagocytic System (MPS, also called Lymphoreticular System or Reticuloendothelial System, RES)
+
{| class="wikitable mw-collapsible mw-collapsed"
 +
! colspan=2|1. Mononuclear Phagocytic System &nbsp;
 +
|-
 +
| valign=top|Mononuclear Phagocytic System (MPS, also called Lymphoreticular System or Reticuloendothelial System, RES)
 
{|
 
{|
 
| [[File:Monocyte 01.jpg|400px]]  
 
| [[File:Monocyte 01.jpg|400px]]  
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* monocytes entering the connective tissue differentiate into '''macrophages''')
 
* monocytes entering the connective tissue differentiate into '''macrophages''')
 
| Non-circulating (fixed) tissue '''macrophages''' (MΦ)  
 
| Non-circulating (fixed) tissue '''macrophages''' (MΦ)  
* found throughout the body ([[:File:Liver_structure_cartoon.jpg|Liver, Kuffer cells]]), spleen, nodes and other tissues.
+
* found throughout the body ([[:File:Liver_structure_cartoon.jpg|Liver, Kupffer cells]]), spleen, nodes and other tissues.
 +
|}
 +
 
 
|}
 
|}
  
===2. Lymphoid System===
+
{| class="wikitable mw-collapsible mw-collapsed"
Adaptive immunity functional cells are the '''lymphocytes''' (B, T, NK) and '''dendritic cells''' (process antigen and present it on their surface, monocyte precursor derived).  
+
! 2. Lymphoid System &nbsp;
 +
|-
 +
| Adaptive immunity functional cells are the '''lymphocytes''' (B, T, NK) and '''dendritic cells''' (process antigen and present it on their surface, monocyte precursor derived).  
  
# '''Antibody-mediated''' - B Lymphocyte secreting antibody = '''Plasma Cell'''
+
# '''Antibody-mediated''' - B Lymphocyte (B cell) when secreting antibody = '''plasma cell''' - develop in bone marrow
# '''Cell-mediated''' - T Lymphocytes form '''memory cell''', Cytotoxic T cells, T helper cell  
+
# '''Cell-mediated''' - T Lymphocytes (T cell) form '''memory cell''', Cytotoxic T cells, T helper cell - develop in thymus
  
  
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{| class="wikitable mw-collapsible mw-collapsed"
 
{| class="wikitable mw-collapsible mw-collapsed"
!  Lymphocyte Electron Micrographs
+
!  Lymphocyte Electron Micrographs &nbsp;
 
|-  
 
|-  
 
| Histologically, there is little difference in appearance between T and B lymphocytes until activated.
 
| Histologically, there is little difference in appearance between T and B lymphocytes until activated.
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|}
 
|}
  
===Lymphocyte Circulation===
+
'''Lymphocyte Circulation'''
 
 
 
* Microbial '''antigens''' are carried into a lymph node by '''dendritic cells''', which enter via afferent lymphatic vessels draining an infected tissue.  
 
* Microbial '''antigens''' are carried into a lymph node by '''dendritic cells''', which enter via afferent lymphatic vessels draining an infected tissue.  
 
* '''T and B cells''' enter the lymph node via an artery and migrate out of the bloodstream through postcapillary venules.  
 
* '''T and B cells''' enter the lymph node via an artery and migrate out of the bloodstream through postcapillary venules.  
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'''Links:''' [http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=mboc4&part=A4419 MBoC Chapter 24 - The Adaptive Immune System] | [http://www.ncbi.nlm.nih.gov/books/NBK26921/figure/A4442 MBoC Figure 24-14. The path followed by lymphocytes as they continuously circulate between the lymph and blood] | [http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=imm Immunobiology]
 
'''Links:''' [http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=mboc4&part=A4419 MBoC Chapter 24 - The Adaptive Immune System] | [http://www.ncbi.nlm.nih.gov/books/NBK26921/figure/A4442 MBoC Figure 24-14. The path followed by lymphocytes as they continuously circulate between the lymph and blood] | [http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=imm Immunobiology]
 +
|}
  
  
==Lymph Vessels==
+
==Diffuse Lymphatic Tissue==
 
 
Three main types (capillaries, collecting vessels, ducts) based on size and morphology.
 
 
 
* Remember anatomy acronym - '''NAVL''' = Nerve, Artery, Vein and Lymph.
 
 
 
 
 
===Lymph Capillaries===
 
[[File:Lymphatic capillary.jpg]]
 
 
 
Begin as blind-ending tubes in connective tissue, larger than blood capillaries, very irregularly shaped.
 
 
 
[[File:Intestine_histology_004.jpg|300px]][[File:Intestine histology 001.jpg|300px]]
 
 
 
Jejunum lacteal (lymphatic capillary of small intestine villi,  absorbs dietary fats)
 
 
 
===Lymph Collecting Vessels===
 
[[File:Lymphatic_vasculature_03.jpg|400px]]
 
 
 
Larger and form valves, morphology similar to lymph capillaries. Lymphangion
 
 
 
===Lymph Ducts===
 
Smooth muscle cells in wall, 1 or 2 layers.
 
 
{|
 
{|
| [[File:Gray599-1.jpg]]
+
! Diffuse Lymphatic Tissue Locations
 +
|-
 +
| valign=top|respiratory passage, alimentary canal, ocular surface, and urogenital tract.
  
Thoracic and right lymphatic ducts
+
* '''MALT''' - '''M'''ucosa '''A'''ssociated '''L'''ymphoid '''T'''issue
|
+
** MALT - initiates immune responses to specific antigens encountered along all mucosal surfaces.
 +
** '''NALT''' - '''N'''asal '''A'''ssociated  '''L'''ymphoid '''T'''issue
 +
** '''BALT''' - '''B'''ronchus '''A'''ssociated  '''L'''ymphoid '''T'''issue
 +
** '''GALT''' - '''G'''ut '''A'''ssociated '''L'''ymphatic '''T'''issue
  
[[File:Lymphatic_vasculature_04.jpg|300px]]
 
 
 
Lymph
 
 
 
* Fluid portion of lymphatic circulation
 
* blood plasma will leave blood vessels into surrounding tissues
 
* adds to normal tissue interstitial fluid
 
* surplus of liquid needs to be returned to circulation
 
* Lymph vessels provide unidirectional flow of this liquid
 
|}
 
 
 
 
==Diffuse Lymphatic Tissue==
 
[[File:Lymphatic-system-tonsil-MALT.jpg|thumb|400px|Tonsil and MALT]]
 
Alimentary canal, respiratory passage and urogenital tract.
 
 
* '''BALT''' - '''B'''ronchus '''A'''ssociated  '''L'''ymphoid '''T'''issue or '''GALT''' - '''G'''ut '''A'''ssociated '''L'''ymphatic '''T'''issue
 
 
* '''Not enclosed by a connective tissue capsule'''
 
* '''Not enclosed by a connective tissue capsule'''
 
* Located in subepithelial tissue - '''lamina propria'''
 
* Located in subepithelial tissue - '''lamina propria'''
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* proliferation and differentiation
 
* proliferation and differentiation
  
 
+
'''Gastrointestinal Tract'''
===Lymph Nodules===
 
* Organized concentrations of lymphocytes
 
** No capsule, covered by epithelia
 
* Nodules are also the unit structure seen in a node
 
* Oval concentrations in meshwork of reticular cells
 
 
 
===Nodule States===
 
* '''Primary Nodule''' - Mainly small lymphocytes
 
* '''Secondary Nodule'''
 
** Central pale region (germinal centre) - Effector cells and macrophages
 
** Dark outer ring (small lymphocytes)
 
 
 
===Gastrointestinal Tract===
 
 
* Oropharynx - Tonsils
 
* Oropharynx - Tonsils
 
* Distal small intestine (ilieum) - Peyer’s Patches  
 
* Distal small intestine (ilieum) - Peyer’s Patches  
 
* Appendix, cecum
 
* Appendix, cecum
 +
| [[File:Lymphatic-system-tonsil-MALT.jpg|400px]]
 +
 +
|-
 +
|}
 +
 +
{| class="wikitable mw-collapsible mw-collapsed"
 +
! colspan=2|Waldeyer’s ring - Mucosal Associated Lymphoid Tissue&nbsp;
 +
|-
 +
| valign=top|Waldeyer’s ring - oral adenoid tissue
  
===Mucosal Associated Lymphoid Tissues===
 
{|
 
| [[File:oesophagus MALT.jpg|300px]]
 
|
 
 
Anatomical location -  Palatine  ('''tonsils'''), Lingual  and Pharyngeal ( '''adenoids''' )
 
Anatomical location -  Palatine  ('''tonsils'''), Lingual  and Pharyngeal ( '''adenoids''' )
 
Ring of oral adenoid tissue:
 
 
* anterior - '''lingual tonsil''' formed by the submucous adenoid collections.
 
* anterior - '''lingual tonsil''' formed by the submucous adenoid collections.
 
* lateral - '''palatine tonsils''' and adenoid collections near the auditory tubes.
 
* lateral - '''palatine tonsils''' and adenoid collections near the auditory tubes.
 
* posterior - '''pharyngeal tonsil''' on the posterior wall of the pharynx.
 
* posterior - '''pharyngeal tonsil''' on the posterior wall of the pharynx.
 
* between main masses are smaller collections of adenoid tissue.
 
* between main masses are smaller collections of adenoid tissue.
 +
| [[File:oesophagus MALT.jpg|300px]]
 
|}
 
|}
  
===Palatine Tonsils===
+
{| class="wikitable mw-collapsible mw-collapsed"
 
+
! colspan=2|Tonsils &nbsp;
[[File:Tonsil_histology_01.jpg|400px]] [[File:Tonsil_histology_02.jpg|400px]]
+
|-
 
+
| valign=top|'''Palatine Tonsils'''
 
 
 
* the "tonsils", lateral wall of oropharynx
 
* the "tonsils", lateral wall of oropharynx
 
* covered by '''stratified squamous epithelium'''
 
* covered by '''stratified squamous epithelium'''
* numerous crypts (10-20) infolds of surface epithelium
+
* numerous '''crypts''' (10-20) in-folds of surface epithelium
* Afferent lymph vessels absent
+
** initial site of [https://www.healthdirect.gov.au/tonsillitis tonsillitis]
* Efferent lymph vessels are present
+
 
 +
'''Tonsilar Crypt''' (crypt) - palatine tonsil squamous epithelium infold, with intraepithelial passages containing non-epithelial cells. Functions include: [https://www.ncbi.nlm.nih.gov/pubmed/7559106 PMID 7559106]
 +
# intimate contact between immune response effector cells
 +
# facilitate transport of antigens
 +
# synthesise secretory components
 +
# contain a pool of immunoglobulins
  
===Lingual Tonsils===
+
* '''A'''fferent lymph vessels - absent
 +
* '''E'''fferent lymph vessels - present
 +
* [https://www.ncbi.nlm.nih.gov/pubmed/7559106 PMID 7559106]
 +
| [[File:Tonsil_histology_01.jpg|400px]] [[File:Tonsil_histology_02.jpg|400px]]
 +
|-
 +
| Lingual Tonsils
 
* lamina propria root of tongue
 
* lamina propria root of tongue
 
* covered by '''stratified squamous epithelium'''
 
* covered by '''stratified squamous epithelium'''
 
* salivary glands and skeletal muscle are directly adjacent
 
* salivary glands and skeletal muscle are directly adjacent
 
+
| Pharyngeal Tonsils
===Pharyngeal Tonsils===
 
 
* '''adenoids''' or nasopharyngeal tonsils, upper posterior part of throat
 
* '''adenoids''' or nasopharyngeal tonsils, upper posterior part of throat
* covered by a '''pseudostratified ciliated epithelium''' with goblet cells
+
* covered by a '''pseudostratified ciliated epithelium''' with goblet cells (respiratory epithelium)
 
+
|}
===Peyer's Patch===
+
===Peyer’s Patches===
* located in the ileum
+
{| class="wikitable mw-collapsible mw-collapsed"
 +
! Peyer's Patch &nbsp;
 +
|-
 +
| Located in the ileum (small intestine)
 
{|
 
{|
 +
| [[File:Peyers patches ileocolonoscopy 01.jpg|300px]]
 
| [[File:Peyer's patch 01.jpg|300px]]  
 
| [[File:Peyer's patch 01.jpg|300px]]  
 
| [[File:Peyer's patch 02.jpg|300px]]
 
| [[File:Peyer's patch 02.jpg|300px]]
 
|-
 
|-
| Peyer's Patch, Ileum
+
| Peyers patches (ileocolonoscopy)
| microfold cells or M-cells (transport gut lumen organisms and particles to immune cells across the epithelial barrier).
+
| Peyer's Patch (histology)
 +
| Microfold cells or [https://www.ncbi.nlm.nih.gov/pubmed/8768493 M-cells]<br>(transport gut lumen organisms and particles to immune cells across the epithelial barrier).
 +
 
 +
Intestinal IgA responses synthesis/secretion.
 
|}
 
|}
  
Line 268: Line 300:
 
|-  
 
|-  
 
| {{External Links}}  
 
| {{External Links}}  
* Learn how the Peyer's Patches function in the Gut Mucosa immune function in this [http://www.nature.com/ni/multimedia/mucosal/animation/index.html Nature Immunology Animation - Immunology in the Gut Mucosa]
 
 
* Peyer's Patches are named after Johann Conrad Peyer (1653 – 1712) a Swiss anatomist who first described these specialised structures.
 
* Peyer's Patches are named after Johann Conrad Peyer (1653 – 1712) a Swiss anatomist who first described these specialised structures.
 +
* Learn how the Peyer's Patches function in the Gut Mucosa immune function in this [https://youtu.be/gnZEge78_78 Nature Immunology Animation - Immunology in the Gut Mucosa]
 +
 +
<html5media width="650" height="400">https://www.youtube.com/embed/gnZEge78_78</html5media>
 +
|}
 
|}
 
|}
 +
==Lymph Nodes==
 +
===Lymph Node Anatomy===
 +
{| class="wikitable mw-collapsible mw-collapsed"
 +
! Lymph Node Anatomy  &nbsp;
 +
|-
 +
| valign=top|
 +
* Location throughout the entire body - concentrated in axilla, groin, lung, gastrointestinal tract mesenteries
 +
* Small (1 mm - 2 cm) encapsulated organ  (diffuse lymphoid tissue - no capsule)
 +
* Antigen transformed lymphocytes from the blood
 +
* In lymph vessel pathways “filter” lymph
 +
** '''Afferent''' - towards node (A - arrives at the node)
 +
** '''Efferent''' - away from node (E - exits the node)
  
 +
[[File:Gastrointestinal tract intestine immune cartoon 01.jpg|300px]]
  
 +
Mesenteric lymph nodes
 +
| [[File:Lymphatic-system-overview.jpg|600px]]
 +
|-
 +
|}
  
==Lymph Nodes==
+
===Lymph Node Functions===
[[File:Lymphatic-system-overview.jpg]]
+
{| class="wikitable mw-collapsible mw-collapsed"
 +
! colspan=2|Lymph Node Functions &nbsp;
 +
|-
 +
| valign=top|
 +
* In lymph vessel pathways “filter” (surveillance) lymph
 +
* '''Immune''' - detect infections from peripheral tissues
 +
** skin, respiratory tract, gastrointestinal tract, etc.
 +
* secondary lymphoid organ
 +
* return extracellular fluid to circulation
 +
| [[File:Lymph node structure.jpg|400px]]
 +
|-
 +
|}
 +
 
 +
===Lymph Node Structure===
 +
 
 +
{| class="wikitable mw-collapsible mw-collapsed"
 +
! colspan=2|Lymph Node Structure &nbsp;
 +
|-  
 +
| [[File:Lymph node cartoon.jpg|400px]]
  
 +
Simplified structure
 +
| [[File:Lymph node cartoon 02.jpg|400px]]
  
* Location throughout the entire body - Concentrated in axilla, groin, mesenteries
+
Lymphocyte (T and B) Traffic
* Encapsulated organ (1 mm - 2 cm)
 
* Antigen transformed lymphocytes from the blood
 
* In lymph vessel pathways “filter”
 
* Afferent- towards node
 
* Efferent- away from node
 
  
 +
# Enter from high endothelial venules (HEVs also called post-capillary venules)
 +
# Spend 8 to 24 h in the lymph node interstitium.
 +
# Enter a network of medullary sinuses.
 +
# Drain from sinuses into efferent lymphatic vessels.
 +
|-
 +
| [[File:Lymph node structure 02.jpg]]
 +
| '''Lymph pathway'''
 +
# Afferent vessel
 +
# Subcapsular sinus
 +
# Paratrabecular sinus
 +
# Medullary sinus
 +
# Efferent vessel
  
Lymph flow
+
Watch T and B Lymphocytes Move&nbsp;
* enters the node through '''afferent vessels'''
+
{{Lymph Node Movie 7}}
* filters through the '''sinuses'''
+
{{Lymph Node Movie 8}}
* leaves through '''efferent vessels'''
+
|-
 +
| colspan=2|[[File:Lymph_node_cartoon_01.jpg|600px]]
 +
|}
  
===Lymph Node Structure===
+
===Lymph Node Histology===
[[File:Lymph_node_cartoon_01.jpg|Lymph_node_cartoon_01.jpg]]
+
{| class="wikitable mw-collapsible mw-collapsed"
 +
! Lymph Node Histology &nbsp;
 +
|-
 +
[[File:Lymph node cartoon 03.jpg|600px]]
  
 
Connective Tissue
 
Connective Tissue
Line 299: Line 383:
 
* '''Reticular Tissue''' - Reticular cells and fibers, supporting meshwork (collagen type III)
 
* '''Reticular Tissue''' - Reticular cells and fibers, supporting meshwork (collagen type III)
 
** Reticular cell produces reticular fibers ('''collagen type III''') and surrounds the fibers with its cytoplasm
 
** Reticular cell produces reticular fibers ('''collagen type III''') and surrounds the fibers with its cytoplasm
** reticular fibbers can also be produced by fibroblasts
+
** reticular fibres can also be produced by fibroblasts
  
<gallery>
+
{|
File:Lymph node cartoon 03.jpg|Cartoon with histology features
+
! Subcapsular Sinus
File:Lymph node histology 01.jpg|Subcapsular Sinus (marginal sinus, continuation of trabecular sinus)
+
! Follicle
File:Lymph node histology 02.jpg|Follicle
+
! Germinal Centre
File:Lymph node histology 03.jpg|Germinal Centre
+
|-
File:Lymph node histology 04.jpg|Medullary Cords and Sinuses
+
| [[File:Lymph node histology 01.jpg|300px]]
File:Lymph node histology 05.jpg|High Endothelial Venules
+
 
File:Lymph_node_histology_06.jpg|Macrophages
+
(marginal sinus, continuation of trabecular sinus)
</gallery>
+
| [[File:Lymph node histology 02.jpg|300px]]
 +
| [[File:Lymph node histology 03.jpg|300px]]
 +
|-
 +
! Medullary Cords and Sinuses
 +
! High Endothelial Venues
 +
! Macrophages
 +
|-
 +
| [[File:Lymph node histology 04.jpg|300px]]
 +
| [[File:Lymph node histology 05.jpg|300px]]
 +
| [[File:Lymph_node_histology_06.jpg|300px]]
 +
|}
 +
 
 +
{{Lymph node cartoons}}
  
 +
'''Links:''' [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A47 Immunobiology - Figure 1.8. Organization of a lymph node] |  [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4399774/figure/F1/  Figure - Germinal centre development in lymph nodes] | [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5492966/figure/F1/?report=objectonly Figure - Vascular-Stromal Compartment]
 +
|}
  
 +
==Thymus ==
 +
===Thymus Anatomy===
 +
{| class="wikitable mw-collapsible mw-collapsed"
 +
! colspan=2|Thymus Anatomy
 +
|-
 +
| [[File:Thymus cartoon.jpg|400px]]
 +
| [[File:Gray1178.jpg|400px]]
 +
|-
 +
| adult thymus - bilobed, superior mediastinum, anterior to heart
 +
| infant thymus - large
 +
|}
 
{|
 
{|
| Lymphocyte (T and B) Traffic
+
! colspan=2|Thymus Involution
 +
|-
 +
| [[File:Fetal thymus weight growth graph.jpg|400px]]
 +
| valign=top|'''Overall Size Changes with age'''
 +
* birth 10-15 g
 +
* puberty 30-40 g
 +
* after puberty - involution
 +
** replaced by adipose tissue
 +
* middle-aged 10 g
 +
|}
 +
 
 +
===Thymus Functions===
 +
{| class="wikitable mw-collapsible mw-collapsed"
 +
! colspan=2|Thymus Functions &nbsp;
 +
|-
 +
| valign=top|
 +
* specialised thymus microenvironments allow the production of self-tolerant T-cells (T lymphocytes) from immature precursors.
 +
** immature precursors enter the thymus
 +
** differentiate and undergo selection by thymic epithelial cell (TEC) subtypes
 +
** mature release into circulation of these cells
 +
* destruction of cells that recognise self antigens
 +
* T-cells kill infected and oncogenic cells
 +
 
  
# Enter from high endothelial venules (HEVs also called post-capillary venules)
+
'''T Cells  maturation within the thymus'''
# Spend 8 to 24 h in the lymph node interstitium.
 
# Enter a network of medullary sinuses.
 
# Drain from sinuses into efferent lymphatic vessels.
 
  
See also [[:File:Lymph node cartoon 02.jpg|Image - Cell Trafficking into and out of Lymph Nodes]].
+
# '''T cell progenitors''' enter the thymus at the cortex/medulla border via post–capillary venules
| {{Lymph Node Movie 7}}
+
# '''migrate''' toward the capsule in response to chemokine signalling.  
 +
# '''cortex''' - thymocytes undergo positive selection by cTECs then migrate to the medulla
 +
# '''medulla''' - thymocytes are screened for reactivity to tissue-restricted self antigens expressed by mTECs.  
 +
# '''Mature T cells''' exit the thymus via blood or lymphatic vessels in response to a sphingosine-1-phosphate (S1P) gradient.
  
T and B motility
+
| [[File:Thymus structure and function cartoon01.jpg|600px]]
|  
+
|-
{{Lymph Node Movie 8}}
+
| [[File:Mouse adult thymus 11.jpg|200px]]
  
T and B interaction
+
Macrophages phagocytosis of T cells
|[[File:Lymph node histology 05.jpg|200px]]
+
{{Thymus Movie 1}}
  
High Endothelial Venules
+
| [[File:T and B lymphocytes EM09.jpg|400px]]
  
See also [[:File:Lymph node - high endothelial venule.jpg|Lymphocyte Migration at High Endothelial Venule Model]]
+
EM - T and B lymphocytes (look the same)
 
|}
 
|}
  
'''Links:''' [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A47 Immunobiology - Figure 1.8. Organization of a lymph node]
+
===Thymus Structure===
 +
 
 +
{| class="wikitable mw-collapsible mw-collapsed"
 +
! Thymus Structure &nbsp;
 +
|-
 +
'''Structure Overview'''
 +
[[File:Thymus histology 06.jpg|400px|right]]
 +
* Connective tissue capsule (thin) with numerous trabeculae (septa)
 +
** major blood vessels run in CT
 +
* Lobules containing '''cortex''' and '''medulla''' regions
 +
** medullary regions are continuous (connected together)
 +
* NOT supplied by afferent lymph vessels
 +
 
 +
 
 +
'''Blood-Thymic Barrier'''
 +
* Blood vessels are separated from thymus cortex by epithelioreticular cells.
 +
* impermeable to most macromolecules.
 +
* Barrier layers: capillary endothelium - endothelial basal lamina- perivascular CT sheath - basal lamina of epithelioreticular cells - epithelioreticular cell sheath
  
 +
{|
 +
|-bgcolor="F5FAFF"
 +
! Thymus Epithelioreticular cells (TEC)
 +
! Macrophages
 +
! Lymphocytes
 +
|-
 +
|
 +
* Abundant, eosinophilic, large, ovoid and light nucleus 1-2 nucleoli
 +
* sheathe cortical capillaries
 +
* form an epitheloid layer
 +
* maintain microenvironment for development of T-lymphocytes in cortex (thymic epitheliocytes)
 +
|
 +
* cortex and medulla
 +
* difficult to distinguish from reticular cells in {{HE}}
 +
* remove auto-reactive  T-lymphocytes
 +
|
 +
* located in cortex and medulla
 +
* more numerous (denser) in cortex
 +
* majority are developing T-lymphocytes (= thymic lymphocytes or thymocytes)
 +
|}
 +
|}
  
==Thymus==
+
===Thymus Histology===
[[File:Lymphatic-system-thymus.jpg|600px]]
+
{| class="wikitable mw-collapsible mw-collapsed"
 +
! Thymus Histology &nbsp;
 +
|-
 +
 +
* Capsule (thin) with trabecular or septa (dense connective tissue)
  
[[File:Thymus cartoon.jpg|thumb|Adult Thymus]]
+
[[File:Thymus histology 01.jpg|600px]]
[[File:Gray1178.jpg|thumb|Fetal thymus anatomy]]
 
* Superior mediastinum, anterior to heart
 
* Bilobed lymphoepithelial organ
 
** Contains reticular cells but no fibers
 
* Stem lymphocytes
 
** proliferate and differentiate
 
** forms long-lived T- lymphocytes
 
  
===Thymus Cells===
+
[[File:Thymus histology 06.jpg|600px]]
  
* '''Reticular cells'''
+
Infant thymus
** Abundant, eosinophilic, large, ovoid and light nucleus 1-2 nucleoli
 
** sheathe cortical capillaries
 
** form an epitheloid layer
 
** maintain microenvironment for development of T-lymphocytes in cortex (thymic epitheliocytes)
 
* '''Macrophages'''
 
** cortex and medulla
 
** difficult to distinguish from reticular cells in H&E
 
* '''Lymphocytes'''
 
** cortex and medulla - more numerous (denser) in cortex
 
** majority of them developing T-lymphocytes (= thymic lymphocytes or thymocytes)
 
  
===Development Changes===
+
{|
{Changes with age
+
! Fetal thymus
Overall Size
+
! Young medulla
* birth 10-15 g
+
! Young cortex
* puberty 30-40 g, after puberty - involution
+
|-
* middle-aged 10 g, replaced by adipose tissue
+
| [[File:Fetal thymus.jpg|300px]]
 +
| [[File:Thymus - young 01.jpg|300px]]
 +
| [[File:Thymus - young 02.jpg|300px]]
 +
|}
  
Histology
 
<gallery>
 
File:Fetal thymus.jpg|Fetal thymus
 
File:Thymus - young 01.jpg‎|Young medulla
 
File:Thymus - young 02.jpg‎|Young cortex
 
</gallery>
 
  
===Adult Thymus===
 
 
{|
 
{|
 +
! Adult Thymus
 +
|-
 
| [[File:Thymus adult.jpg|300px]]
 
| [[File:Thymus adult.jpg|300px]]
|
+
|  
 
+
* Cortical lymphoid tissue is replaced by adipose tissue (involution)
* Cortical lymphoid tissue is replaced by adipose tissue
 
 
* Increase in size of thymic corpuscles
 
* Increase in size of thymic corpuscles
 
* '''Thymic corpuscle''' - (Hassall’s corpuscle) mass of concentric epithelioreticular cells.
 
* '''Thymic corpuscle''' - (Hassall’s corpuscle) mass of concentric epithelioreticular cells.
 +
|}
  
[[File:Thymus - young 01.jpg|300px]]
 
  
 
{{Thymus Histology}}
 
{{Thymus Histology}}
 
|}
 
|}
 
 
==Spleen==
 
==Spleen==
[[File:Lymphatic-system-spleen.jpg|600px]]
+
===Spleen Anatomy===
 
+
{|
 
+
! Spleen Anatomy
===Spleen Function===
+
|-
[[File:Spleen anatomy.jpg|thumb]]
+
| [[File:Spleen anatomy.jpg|400px]]
[[File:Gray1039.jpg|thumb]]
+
| [[File:Gray1039.jpg|400px]]
 +
|-
 +
| left hypochondriac region
 +
| almost entirely surrounded by peritoneum adherent to its capsule
 +
|}
 +
===Spleen Functions===
 +
{| class="wikitable mw-collapsible mw-collapsed"
 +
! Spleen Functions &nbsp;
 +
|-
 +
|
 
# '''Immune''' - filters blood in much the way that the lymph nodes filter lymph.  
 
# '''Immune''' - filters blood in much the way that the lymph nodes filter lymph.  
 
## '''Lymphocytes''' in the spleen react to pathogens in the blood and attempt to destroy them.
 
## '''Lymphocytes''' in the spleen react to pathogens in the blood and attempt to destroy them.
 
## '''Macrophages''' then engulf the resulting debris, the damaged cells, and the other large particles.
 
## '''Macrophages''' then engulf the resulting debris, the damaged cells, and the other large particles.
 
# '''Red Blood Cell Removal''' - spleen (and liver) removes old and damaged erythrocytes from the circulating blood.  
 
# '''Red Blood Cell Removal''' - spleen (and liver) removes old and damaged erythrocytes from the circulating blood.  
# '''Blood Reservoir''' - The sinuses in the spleen also act as a reservoir for blood.
+
# '''Blood Reservoir''' - The sinuses in the spleen also act as a reservoir for blood. In emergencies (haemorrhage) smooth muscle in the vessel walls and in the capsule of the spleen contracts, squeezes blood out of the spleen into the general circulation.
** In emergencies, such as hemorrhage, smooth muscle in the vessel walls and in the capsule of the spleen contracts.
+
|}
** This squeezes the blood out of the spleen into the general circulation.
+
 
 +
===Spleen Structure===
 +
 
 +
{| class="wikitable mw-collapsible mw-collapsed"
 +
! Spleen Structure &nbsp;
 +
|-
 +
|  [[File:Spleen structure cartoon 01.jpg|800px]]
 +
 
 +
* '''afferent splenic artery''' branches into central arterioles, which are sheathed by white pulp areas.
 +
* '''white pulp''' areas consist of the T-cell zone (also known as the periarteriolar lymphoid sheath, PALS), arterioles and B-cell follicles.
 +
* arterioles end in cords in the '''red pulp''', from where the blood runs into venous sinuses that collect into the '''efferent splenic vein'''.
 +
* larger arteries and veins run together in connective-tissue trabeculae, which are continuous with the capsule that surrounds the spleen.
  
===Structure===
+
[[File:Spleen structure cartoon 02.jpg|600px]]
* Capsule, trabeculae (dense connective tissue)
+
 
* Splenic pulp white pulp, red pulp - based on appearance and cell content.
+
Red pulp
 +
|}
 +
 
 +
===Spleen Histology===
 +
{| class="wikitable mw-collapsible mw-collapsed"
 +
! Spleen Histology &nbsp;
 +
|-
 +
 +
* Capsule with trabeculae (dense connective tissue)
 +
* Reticular fibroblasts - reticular fibres (Type III collagen)
 +
 
 +
[[File:Spleen histology 06.jpg|600px]]
  
[[File:Spleen_histology_05.jpg|thumb|White pulp -periarterial lymphoid sheath (PALS)]]
 
 
{|
 
{|
|
+
|-
'''White Pulp'''
+
! bgcolor="CEDFF2" width=200px|White Pulp
* lymphocytes surround central arteries
+
! bgcolor="salmon" width=200px|Red Pulp
* as periarterial lymphoid sheath (PALS)
+
|-
|
+
| valign=top|
'''Red Pulp'''
+
* lymph follicle
* Red blood cells
+
* germinal center
* Splenic cords and sinuses
+
* central artery
 +
** periarterial lymphoid sheath (PALS)
 +
| valign=top|
 +
* splenic cords
 +
** macrophages
 +
** reticular fibroblasts
 +
* splenic sinuses
 +
** endothelium (discontinuous structure)
 +
|}
 +
{|
 +
! Overview - red and white pulp
 +
! Overview - blood vessels
 +
! Red pulp
 +
|-
 +
| [[File:Spleen_histology_01.jpg|300px]]
 +
| [[File:Spleen_histology_02.jpg|300px]]
 +
| [[File:Spleen_histology_03.jpg|300px]]
 
|}
 
|}
  
'''Reticular Fibers''' (type III collagen) act as supporting meshwork.
+
'''Reticular Fibers''' (type III collagen) act as supporting meshwork (can be seen in Silver stained preparations)
 
+
{|
<gallery>
+
| [[File:Spleen_histology_05.jpg|300px]]
File:Spleen_histology_01.jpg|Overview Red and White Pulp
+
| [[File:Spleen_histology_04.jpg|300px]]
File:Spleen_histology_02.jpg|Overview Red and White Pulp
+
|}
File:Spleen_histology_03.jpg|Cords and Sinuses
 
File:Spleen_histology_05.jpg|Reticular Fibre overview
 
File:Spleen_histology_04.jpg|Reticular Fibre detail
 
File:Spleen_histology_06.jpg|unlabeled red and white pulp
 
File:Spleen_histology_07.jpg|unlabeled red pulp and macrophages
 
File:Spleen_histology_08.jpg|unlabeled white pulp germinal centre
 
File:Spleen_histology_09.jpg|unlabeled reticular fibre
 
File:Spleen_histology_10.jpg|unlabeled white pulp reticular
 
File:Spleen_histology_11.jpg|unlabeled red pulp reticular
 
</gallery>
 
  
 
{{Spleen Histology}}
 
{{Spleen Histology}}
 +
|}
  
  
  
 +
==Additional Information==
  
==Additional Information==
 
 
{{Med Prac additional Information}}
 
{{Med Prac additional Information}}
  
If you have comments or questions specifically related to this lecture, please leave them on the [[Student:SH Lecture - Lymphatic Structure and Organs|Student lecture feedback page]].
+
{|
 +
! Janeway’s Immunobiology  &nbsp;
 +
|-
 +
| [[File:Mark_Hill.jpg|left|50px]] A useful resource textbook for further reading on '''Lymphatic Structure and Organs''' is [http://www.ncbi.nlm.nih.gov/books/NBK10757/ Immunobiology] 5th edition The Immune System in Health and Disease Charles A Janeway, Jr, Paul Travers, Mark Walport, and Mark J Shlomchik. Open links in a new tab if you wish to refer back to this lecture page.
 +
 
 +
I have included some links in this table below to specific notes and there is also available a [[Talk:SH_Lecture_-_Lymphatic_Structure_and_Organs#Immunobiology_3|complete list of contents]].
 +
 
 +
{{External Links}}
 +
 
 +
[http://www.ncbi.nlm.nih.gov/books/NBK10757/ Immunobiology] 5th edition The Immune System in Health and Disease Charles A Janeway, Jr, Paul Travers, Mark Walport, and Mark J Shlomchik.
 +
 
 +
'''Part I. An Introduction to Immunobiology and Innate Immunity''' Chapter 1. Basic Concepts in Immunology
 +
* [http://www.ncbi.nlm.nih.gov/books/NBK27092/ The components of the immune system]
 +
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A40 Figure 1.3 All the cellular elements of blood, including the lymphocytes of the adaptive immune system, arise from hematopoietic stem cells in the bone marrow]
 +
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A41 Figure 1.4 Myeloid cells in innate and adaptive immunity]
 +
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A42 Figure 1.5 Lymphocytes are mostly small and inactive cells]
 +
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A43 Figure 1.6 Natural killer (NK) cells]
 +
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A45 Figure 1.7 The distribution of lymphoid tissues in the body]
 +
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A47 Figure 1.8 Organization of a lymph node]
 +
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A48 Figure 1.9 Organization of the lymphoid tissues of the spleen]
 +
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A49 Figure 1.10 Organization of typical gut-associated lymphoid tissue]
 +
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A51 Figure 1.11 Circulating lymphocytes encounter antigen in peripheral lymphoid organs]
 +
* [http://www.ncbi.nlm.nih.gov/books/NBK27092/#A52 Summary to Chapter 1]
 +
 
 +
'''Part III. The Development of Mature Lymphocyte Receptor Repertoires''' Chapter 7. The Development and Survival of Lymphocytes
 +
* [http://www.ncbi.nlm.nih.gov/books/NBK27123/ Generation of lymphocytes in bone marrow and thymus]
 +
** [http://www.ncbi.nlm.nih.gov/books/NBK27123/figure/A803 Figure 7.3 The early stages of B-cell development are dependent on bone marrow stromal cells]
 +
** [http://www.ncbi.nlm.nih.gov/books/NBK27123/figure/A806 Figure 7.5 The development of a B-lineage cell proceeds through several stages marked by the rearrangement and expression of the immunoglobulin genes]
 +
** [http://www.ncbi.nlm.nih.gov/books/NBK27123/figure/A809 Figure 7.7 The cellular organization of the human thymus]
 +
** [http://www.ncbi.nlm.nih.gov/books/NBK27123/figure/A818 Figure 7.13Thymocytes at different developmental stages are found in distinct parts of the thymus]
 +
* [http://www.ncbi.nlm.nih.gov/books/NBK27150/ Survival and maturation of lymphocytes in peripheral lymphoid tissues]
 +
* [http://www.ncbi.nlm.nih.gov/books/NBK27123/#A819 Summary to Chapter 7]
 +
|}
  
''The following is not part of the lecture and is for reference purposes only.''
 
  
 
[[File:SHsmall.jpg|left]] [[SH Practical - Lymphatic Structure and Organs|'''SH Practical - Lymphatic Structure and Organs''']] associated practical support page. Note that virtual slides will be used in the associated practical class and this linked page is provided for student self-directed learning of concepts from the virtual slides.
 
[[File:SHsmall.jpg|left]] [[SH Practical - Lymphatic Structure and Organs|'''SH Practical - Lymphatic Structure and Organs''']] associated practical support page. Note that virtual slides will be used in the associated practical class and this linked page is provided for student self-directed learning of concepts from the virtual slides.
Line 467: Line 687:
 
</gallery>
 
</gallery>
  
 +
{| class="wikitable mw-collapsible mw-collapsed"
 +
! colspan="4"|Lymph Node Subcapsular Space Functions? &nbsp;
 +
|-
 +
| The subcapsular region is not only the initial entry site for lymph flow into the node, but has also been shown to have important immune functions.
 +
 +
'''Macrophages'''
 +
 +
Subcapsular sinus macrophages clear lymph-borne viruses and present them to antiviral B cells.{{#pmid:17934446|PMID17934446}} This has also been recently demonstrated in the mouse model.{{#pmid:30502023|PMID30502023}}
 +
 +
'''Memory B cells'''
 +
 +
Memory B cells have also been shown to be reactivated in subcapsular proliferative foci of lymph nodes.{{#pmid:30135429|PMID30135429}}
  
{{Lymph node cartoons}}
+
<references/>
 +
|}
  
 
{| class="wikitable mw-collapsible mw-collapsed"
 
{| class="wikitable mw-collapsible mw-collapsed"
! colspan="4"|Mouse Lymphocyte Motility Movies
+
! colspan="4"|Mouse Lymphocyte Motility Movies   &nbsp;
 
|-  
 
|-  
 
| valign="bottom"|{{Lymph Node Movie 1}}
 
| valign="bottom"|{{Lymph Node Movie 1}}
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{| class="wikitable mw-collapsible mw-collapsed"
 
{| class="wikitable mw-collapsible mw-collapsed"
!  Additional Images
+
!  Additional Images   &nbsp;
 
|-  
 
|-  
 
|
 
|
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</gallery>
 
</gallery>
 
|}
 
|}
 +
* [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3144400/figure/F1/ Figure - Gut associated lymphoid tissue (GALT) and systemic mucosal immunity]
  
{| class="wikitable mw-collapsible mw-collapsed"
+
===Nature Immunology - Videos===
! Janeway’s Immunobiology
+
 
|-
+
'''Nature Immunology''' - These are short (5-10 min) animations showing how the immune system monitors the epithelial and environment interface at different anatomical locations.
| [[File:Mark_Hill.jpg|left|50px]] A useful resource textbook for further reading on '''Lymphatic Structure and Organs''' is [http://www.ncbi.nlm.nih.gov/books/NBK10757/ Immunobiology] 5th edition The Immune System in Health and Disease Charles A Janeway, Jr, Paul Travers, Mark Walport, and Mark J Shlomchik. Open links in a new tab if you wish to refer back to this lecture page.
+
 
 +
<html5media width="600" height="400">https://www.youtube.com/embed/_VhcZTGv0CU</html5media>
 +
 
 +
<html5media width="600" height="400">https://www.youtube.com/embed/rgphaHmAC_A</html5media>
  
I have included some links in this table below to specific notes and there is also available a [[Talk:SH_Lecture_-_Lymphatic_Structure_and_Organs#Immunobiology_3|complete list of contents]].  
+
<html5media width="600" height="400">https://www.youtube.com/embed/gnZEge78_78</html5media>
  
{{External Links}}
+
YouTube Links
 +
* [https://youtu.be/_VhcZTGv0CU Immunology of the skin]
 +
* [https://youtu.be/rgphaHmAC_A Immunology of the lung]
 +
* [https://youtu.be/gnZEge78_78 Immunology in the gut mucosa]
  
[http://www.ncbi.nlm.nih.gov/books/NBK10757/ Immunobiology] 5th edition The Immune System in Health and Disease Charles A Janeway, Jr, Paul Travers, Mark Walport, and Mark J Shlomchik.
 
  
'''Part I. An Introduction to Immunobiology and Innate Immunity''' Chapter 1. Basic Concepts in Immunology
+
===Government Sources===
* [http://www.ncbi.nlm.nih.gov/books/NBK27092/ The components of the immune system]
 
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A40 Figure 1.3 All the cellular elements of blood, including the lymphocytes of the adaptive immune system, arise from hematopoietic stem cells in the bone marrow]
 
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A41 Figure 1.4 Myeloid cells in innate and adaptive immunity]
 
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A42 Figure 1.5 Lymphocytes are mostly small and inactive cells]
 
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A43 Figure 1.6 Natural killer (NK) cells]
 
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A45 Figure 1.7 The distribution of lymphoid tissues in the body]
 
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A47 Figure 1.8 Organization of a lymph node]
 
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A48 Figure 1.9 Organization of the lymphoid tissues of the spleen]
 
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A49 Figure 1.10 Organization of typical gut-associated lymphoid tissue]
 
** [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A51 Figure 1.11 Circulating lymphocytes encounter antigen in peripheral lymphoid organs]
 
* [http://www.ncbi.nlm.nih.gov/books/NBK27092/#A52 Summary to Chapter 1]
 
  
'''Part III. The Development of Mature Lymphocyte Receptor Repertoires''' Chapter 7. The Development and Survival of Lymphocytes
+
These information pages provide general information to the public. See how the biology concepts have been simplified to make them more understandable.
* [http://www.ncbi.nlm.nih.gov/books/NBK27123/ Generation of lymphocytes in bone marrow and thymus]
 
** [http://www.ncbi.nlm.nih.gov/books/NBK27123/figure/A803 Figure 7.3 The early stages of B-cell development are dependent on bone marrow stromal cells]
 
** [http://www.ncbi.nlm.nih.gov/books/NBK27123/figure/A806 Figure 7.5 The development of a B-lineage cell proceeds through several stages marked by the rearrangement and expression of the immunoglobulin genes]
 
** [http://www.ncbi.nlm.nih.gov/books/NBK27123/figure/A809 Figure 7.7 The cellular organization of the human thymus]
 
** [http://www.ncbi.nlm.nih.gov/books/NBK27123/figure/A818 Figure 7.13Thymocytes at different developmental stages are found in distinct parts of the thymus]
 
* [http://www.ncbi.nlm.nih.gov/books/NBK27150/ Survival and maturation of lymphocytes in peripheral lymphoid tissues]
 
* [http://www.ncbi.nlm.nih.gov/books/NBK27123/#A819 Summary to Chapter 7]
 
|}
 
  
Learn how the Peyers Patches function in the Gut Mucosa immune function in this [http://www.nature.com/ni/multimedia/mucosal/animation/index.html Nature Immunology Animation - Immunology in the Gut Mucosa]
+
USA
 +
* [https://www.aids.gov/hiv-aids-basics/just-diagnosed-with-hiv-aids/hiv-in-your-body/immune-system-101 Basic AIDS and Immune System Information]
 +
* [http://www.niaid.nih.gov/topics/immunesystem/Pages/default.aspx  NIAD - Immune System]
  
 +
Australia
 +
* [http://www.healthdirect.gov.au/hiv-infection-and-aids Healthdirect HIV/AIDS]
  
 
{| class="wikitable mw-collapsible mw-collapsed"
 
{| class="wikitable mw-collapsible mw-collapsed"
! Blood Cells
+
! Blood Cells   &nbsp;
 
|-  
 
|-  
 
| [[File:Mark_Hill.jpg|left|50px]] Blood cell information shown in the table below is also additional information for reference purposes.
 
| [[File:Mark_Hill.jpg|left|50px]] Blood cell information shown in the table below is also additional information for reference purposes.
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{| class="wikitable mw-collapsible mw-collapsed"
 
{| class="wikitable mw-collapsible mw-collapsed"
! Anatomy of the Human Body (1918) - Lymphatics
+
! Anatomy of the Human Body (1918) - Lymphatics   &nbsp;
 
|-  
 
|-  
 
| [[File:Mark_Hill.jpg|left|50px]] [[Anatomy_of_the_Human_Body_by_Henry_Gray|Anatomy of the Human Body]] Gray (1918) Historic anatomy is good, though there are there are some functional inaccuracies.
 
| [[File:Mark_Hill.jpg|left|50px]] [[Anatomy_of_the_Human_Body_by_Henry_Gray|Anatomy of the Human Body]] Gray (1918) Historic anatomy is good, though there are there are some functional inaccuracies.
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:Textbook Links: [http://www.ncbi.nlm.nih.gov/books/NBK26921/figure/A4429 MBoC Figure 24-6. The development and activation of T and B cells | [http://www.ncbi.nlm.nih.gov/books/NBK26921/figure/A4430/ Figure 24-7. Electron micrographs of nonactivated and activated lymphocytes] | [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A48 Immunobiology - Figure 1.9. Organization of the lymphoid tissues of the spleen]
 
:Textbook Links: [http://www.ncbi.nlm.nih.gov/books/NBK26921/figure/A4429 MBoC Figure 24-6. The development and activation of T and B cells | [http://www.ncbi.nlm.nih.gov/books/NBK26921/figure/A4430/ Figure 24-7. Electron micrographs of nonactivated and activated lymphocytes] | [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A48 Immunobiology - Figure 1.9. Organization of the lymphoid tissues of the spleen]
 
'''Structure''' - Cells, Vessels, Diffuse (extra-nodal tissue), Nodes, Organs.
 
* Cells
 
* Vessels
 
* Diffuse
 
** Mucosal Associated Lymphoid Tissues (MALT)
 
** Extranodal Lymphoid Tissues
 
** Nodules
 
* Lymph Nodes
 
** Position
 
** Structure
 
** Function
 
* Organs
 
** Position, Structure, Function
 
** Thymus
 
** Spleen
 
  
 
== Terms ==
 
== Terms ==
A few key terms associated with the Lymphoid system.
+
A few key terms associated with the lymphoid system.
 
 
* '''adenoid''' - (Greek " +''-oeides ''<nowiki>= in form of) in the form of a gland, glandular; the pharyngeal tonsil. </nowiki>
 
* '''afferent lymph''' - vessel carrying lymph towards a node.
 
* '''Antibody mediated immunity''' - the immune function of plasma cells (active B lymphocytes) secreting antibody which binds antigen.
 
* '''antibodies''' - mammals have five classes (IgA, IgD, IgE, IgG, and IgM)
 
* '''antigen''' - any substance that is recognised by the immune system and stimulates antibody production.
 
* '''appendix''' - is a gut-associated lymphoid tissue located at the beginning of the colon. The anatomy is as a finger-like structure that arises from the cecum. The length (2.5-13 cm) is longer in both infants and children and also has more abundant lymphatic tissue in early life. The wall structure is similar to the small intestine (though with no villi), nor plicae circularis. Lymph nodules surround the lumen of the gastrointestinal tract and extend from the mucosa into the submucosa.
 
* '''B lymphocyte (cell)''' - historically named after a structure called the '''b'''ursa of Fabricius in birds, a source of antibody-producing lymphocytes. These cells develop in the bone marrow. (More? [[Immune_System_Development#Adult_Lymphocyte_Histology|Electron micrographs of nonactivate and activated lymphocytes]])
 
* '''BALT''' - Bronchus Associated Lymphoid Tissue
 
* '''band cell''' - (band neutrophil or stab cell) seen in bone marrow smear, a cell undergoing granulopoiesis, derived from a metamyelocyte, and leading to a mature granulocyte. Also occasionally seen in circulating blood.
 
* '''cecum''' -  (caecum,  Latin, ''caecus'' = "blind") within the gastrointestinal tract a pouch that connects the ileum with the ascending colon of the large intestine.
 
* '''cell''' - has a specific cell biology definition, but is often used instead of "lymphocyte" when describing B and T cells.
 
* '''Cell-mediated immunity''' - the immune function of T lymphocytes.
 
* '''CD''' - (cluster of differentiation) identifies immunological surface markers on cells.
 
* '''CD4+''' - (T helper cells) refers to T lymphocytes that express CD4 (glycoprotein of the immunoglobulin superfamily) on their surface.
 
* '''CD8+''' - (cytotoxic T cells) refers to T lymphocytes that express CD8 (glycoprotein of the immunoglobulin superfamily) on their surface.
 
* '''"clockface"''' - a term used to describe the appearance of plasma cell nuclei due to the clumping of the chromatin at the nucleus periphery. More clearly seen in tissue plasma cells that the bone marrow smear, where they are sometimes confused with the basophilic erythroblasts.
 
* '''cords of Billroth''' - spleen cellular columns located in red pulp. surrounded by splenic sinusoids. Cords contain reticular cells, macrophages, lymphocytes, plasma cells and erythrocytes.
 
* '''cortex''' - outer layer, used in association with medulla (innner layer or core) a general description that can be applied to describing an organ with a layered structure.
 
* '''dendritic cells''' - (DCs) immune cells that function to process antigen and present it on their surface to other immune cells.
 
* '''Effector cells''' - the immune functioning (active) B and T lymphocytes.
 
* '''Efferent lymph''' - vessel carrying lymph away from a node.
 
* '''GALT''' - Gut Associated Lymphatic Tissue
 
* '''haemopoiesis''' (hemopoiesis) formation of blood cells.
 
* '''Hassall's corpuscle''' - thymic corpuscle.
 
* '''HEV''' - (high endothelial venule) within the lymph node these specialised post-capillary venules enables blood lymphocytes to enter a lymph node. Their endothelial cells  express ligands that bind lymphocytes, aiding their adhesion and subsequent transmigration into the lymph node.
 
* '''IgA''' - the main class of antibody in secretions (saliva, tears, milk, and respiratory and intestinal secretions).
 
* '''IgD''' - the immunoglobulin B cell starts to produce as a cell-surface  molecule after leaving the bone marrow.
 
* '''IgE''' - bind Fc receptors (surface of mast cells in tissues and basophils in the blood).
 
* '''IgG''' - the major class of immunoglobulin in the blood.
 
* '''IgM'''  -  the first class of antibody made by a developing B cell, which may switch to making other classes of antibody.
 
* '''immunodeficiency''' - when one or more components of the immune system is defective. (More? [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Search&db=books&rid=imm.section.1494 Immunobiology - immunodeficiency])
 
* '''involution''' - in the Thymus refers to the replacement, mainly in the cortex, of cells by adipose tissue. (More? [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&term=thymus+involution&doptcmdl=Books PubMed- thymus involution]) | [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Search&db=books&rid=cmed6.section.23856#23857 Cancer Medicine - Thymomas and Thymic Tumors])
 
* '''Kupffer cells''' - stellate macrophage cells located in the liver sinusoids, named after Karl Wilhelm von Kupffer (1829 - 1902) a German anatomist who originally identified these cells. (More? [[Gastrointestinal Tract - Liver Development|Liver Development]])
 
* '''lamina propria''' - a layer of loose connective tissue found underneath the epithelium of mucosa.
 
* '''Leukocyte-''' (Greek, lukos= clear, white) white blood cell.
 
* '''lingual'''- related to the tongue.
 
* '''lymph node''' - connective tissue encapsulated lymphoid organ (1mm - 2cm in size), positioned in the pathway of lymph vessels.
 
* '''M cell''' - (microfold cell) found in the follicle-associated epithelium of the Peyer's patch. Function to transport gut lumen organisms and particles to immune cells across the epithelial barrier.
 
* '''macrophage''' - a large highly motile white blood cell which engulfs foreign material (bacteria etc) and both degenerating cells and cell fragments. Found in many different tissues and locations. (More? [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=imm.figgrp.1508 Immunobiology - Defects in phagocytic cells are associated with persistence of bacterial infection])
 
* '''MALT''' - Mucosa Associated Lymphoid Tissue
 
* '''medulla''' - inner layer or core, used in association with cortex (outer layer) a general description that can be applied to describing an organ with a layered structure.
 
* '''Memory Cell''' - effector T cell (lymphocyte)
 
* '''NALT''' - Nasal Associated Lymphoid Tissue.
 
* '''NK cell''' - (Natural killer cell, large granular lymphocytes) are a type of cytotoxic lymphocyte, responding rapidly to virally infected and tumor cells.
 
* '''normoblast''' - seen in bone marrow smear, a developing erythroblast (red blood cell) that still retains a nucleus.
 
* '''parenchyma''' - (Greek = ''enkeim'' "to pour in") cells forming the functional cells of an organ or tissue. These cells carry out the function of the organ at a cellular level, and are not the structural cells, connective tissue, extracellular matrix (stromal).
 
* '''periarterial lymphoid sheath''' - (PALS) in the spleen the white pulp that surrounds the central arteries. (T-lymphocytes,macrophages and plasma cells)
 
* '''Plasma Cell''' - active B cell (lymphocyte) which is secreting antibody. Located in either bone marrow or peripheral lymphoid tissues, these cells have and increased cytoplasmic volume (due to increase rough endoplasmic reticulum) in comparison to the inactive (non-secreting) lymphocyte.
 
* '''secondary lymphoid organs''' - spleen, regional lymph nodes, Peyer’s patches, Isolated Lymphoid Follicles (ILFs), tonsils and Nasal Associated Lymphoid Tissue (NALT).
 
* '''sentinel lymph node''' -  the hypothetical first lymph node or group of nodes reached by metastasizing cancer cells from a primary tumour.
 
* '''splenic sinusoids''' - enlarged spleen capillary spaces located in red pulp and surrounding cords of Billroth.
 
* '''stroma''' - (Greek = "a cover, table-cloth, bedding") tissue forming the framework/support of an organ or tissue. That is the structural cells which form connective tissue and secrete extracellular matrix, rather than the functional cells (parenchymal). All organs can therefore be functionally divided into these 2 components, stromal/parenchymal.
 
* '''Subcapsular sinus''' (=marginal sinus) space lying under the connective tissue capsule which receives lymph from afferent lymphatic vessels.
 
* '''tertiary lymphoid tissue''' - develop at sites of persistent infection or chronic inflammation.
 
* '''Thymic corpuscle''' (=Hassall's corpuscle) a mass of concentric epithelioreticular cells found in the thymus. The number present and size tend to increase with thymus age. (see classical description of Hammar, J. A. 1903 Zur Histogenese und Involution der Thymusdriise. Anat. Anz., 27: 1909 Fiinfzig Jahre Thymusforschung. Ergebn. Anat. Entwickl-gesch. 19: 1-274.)
 
* '''thymic epitheliocytes''' - reticular cells located in the thymus cortex that ensheathe the cortical capillaries, creating and maintain the microenvironment necessary for the development of T-lymphocytes in the cortex.
 
* '''T lymphocyte (cell)''' - named after '''t'''hymus, where they develop, the active cell is responsible for cell-mediated immunity. (More? [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mboc4.figgrp.4430 Electron micrographs of nonactivate and activated lymphocytes])
 
* '''thymus''' - thymus has a key role in the development of an effective immune system as well as an endocrine function. Immune system T cells are essential for responses against infections and research relates to the postnatal development of T cells within the thymus. [[Thymus Development]]
 
* '''tonsils''' - mucosal-associated lymphoid tissues consists of: 2 palatine tonsils (tonsilla palatina), adenoids (tonsilla pharyngealis) and 1 lingual tonsil (tonsilla lingualis)
 
* '''tonsillar ring''' - ring of lymphoid tissue (tonsils) around where the mouth and nasal cavity meet the throat.
 
*''' vermiform appendix''' - see appendix, anatomical region containing gut-associated lymphoid tissue located within the gastrointestinal tract at the beginning of the colon. The anatomy is as a finger-like structure that arises from the cecum. The length (2.5-13 cm) is longer in both infants and children and also has more abundant lymphatic tissue in early life. The wall structure is similar to the small intestine (though with no villi), nor plicae circularis. Lymph nodules surround the lumen of the gastrointestinal tract and extend from the mucosa into the submucosa.
 
  
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{{immune terms}}
  
  
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{{Footer}}
 
{{Footer}}
 
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[[Category:Medicine]][[Category:Immune]] [[Category:Histology]][[Category:2019]]
[[Category:Medicine]][[Category:Immune]] [[Category:Histology]][[Category:2015]]
 

Latest revision as of 14:54, 18 February 2019

Introduction

SHsmall.jpg

This lecture will provide an overview of the lymphoid structure and histology of key cells, vessels, structures and organs lymphoid organs, including the lymph nodes, spleen and thymus, as well as extranodal lymphoid tissues including mucosal associated lymphoid tissues (MALT).

In this lecture I will go through the structures in sequence from cells through to organs, immunity itself is covered in detail elsewhere in the course.


2019 Lecture - Lecture PDF

2019 Lecture Audio
Topic   Audio   Files   Size/Time  
Lymphatics listen | download 18.62 Mb MP3 51:14 min
Note live audio recordings may contain inaccuracies or errors. Refer always to the lecture notes below.


Textbook References  
Hill, M.A. (2019). UNSW Embryology (19th ed.) Retrieved October 18, 2019, from https://embryology.med.unsw.edu.au
Moodle icon2.jpg
Virtual Slides - Lymphatic: Human Blood Smear | Bone Marrow Smear | Thymus (infant) | Thymus (adult 1) | Thymus (adult 2) | Spleen | Spleen (silver stain) | Lymph Node | Lymph Node (silver stain) | Lingual tonsil (tongue} | Pharyngeal tonsil | Appendix (slide access requires Zpass login)
  • Additional background information:
Immune Links: immune | blood | spleen | thymus | Lymphatic | lymph node | Antibody | Med Lecture - Lymphatic Structure | Med Practical | Immune Movies | vaccination | bacterial infection | Abnormalities | Category:Immune
Historic Embryology  
1909 Lymph glands | 1912 Development of the Lymphatic System | 1918 Gray's Lymphatic Images | 1916 Pig Lymphatics | 1919 Chicken Lymphatic | 1921 Spleen | 1922 Pig Stomach Lymphatics | 1932 Cat Pharyngeal Tonsil | Historic Disclaimer
Janeway’s Immunobiology (see in additional information) NCBI Bookshelf A good detailed textbook on the lymphatic system.
Nature Immunology - These are short (5-10 min) animations showing how the immune system monitors the epithelial and environment interface at different anatomical locations.
Histology and cell biology, 3rd edn.jpg
Kierszenbaum, A. L., & Tres, L. L. (2012). Histology and cell biology: An introduction to pathology. Philadelphia, PA: Elsevier Saunders. UNSW Students have online access to the current 3rd edn. through the UNSW Library subscription.


Lecture Archive  

2018 | PDF 2018 | 2017 | 2016 | PDF 2016 | PDF 2015 | 2015 | PDF 2014 | 2014 | 2013 | 2012 | 2010

UNSW Research  
UNSWlogo2017.jpg Some examples of UNSW research on immunity
Structure Function
  1. Cells - blood cells (parenchyma), connective tissue (stroma)
  2. Vessels - lymphatic vessels, thin-walled, valves (NAVL)
  3. Diffuse - (extra-nodal tissue) nodules, Mucosal Associated Lymphoid Tissues (MALT)
  4. Nodes - (historic, "glands")
  5. Organs - thymus, spleen
  1. Immune - “monitor” of body surfaces, internal fluids
  2. Extracellular fluid - "returns" interstitial fluid to circulation
  3. Gastrointestinal tract - "carries" fat and fat-soluble vitamins (SI lacteals)

Lymphatic system

Blood Cells

Blood Cell Development  
Hematopoietic and stromal cell differentiation.jpg
Two Blood Cell Systems
  1. Mononuclear Phagocytic System - circulating monocytes of peripheral blood and non-circulating (fixed) tissue macrophages found throughout the body.
  2. Lymphoid System - lymphocytes, three major types of T, B, and NK.


Lymphoid Organs

  • Central - (primary) Lymphocytes develop from precursor cells in bone marrow and thymus. (see blood marrow image)
  • Peripheral - (secondary) Lymphocytes respond to antigen lymph nodes or spleen.
Blood Cells  
The blood cell information shown below in the table is shown to identify the relative proportions of different cell types in the circulating blood. This information is provided in the lecture as additional information for reference purposes only.

Blood Cell Numbers

The adult ranges of cells / 1 litre (l), total blood volume is about 4.7 to 5 litres. Blood Development | Blood Histology

Red Blood Cells

  • Male: 4.32 - 5.66 x 1012/l
  • Female: 3.88 - 4.99 x 1012/l

Leukocytes (white blood cells)

  • Male: 3.7 - 9.5 x 109/l
  • Female: 3.9 - 11.1 x 109/l

Granulocytes

  • 1.8 - 8.9 x 109/l
    • Neutrophils: 1.5 - 7.4 x 109/l
    • Eosinophils: 0.02 - 0.67 x 109/l
    • Basophils: 0 - 0.13 x 109/l

Non-Granulocytes

  • Monocytes 0.21 - 0.92 x 109/l

Lymphocytes

  • 1.1 - 3.5 x 109/l
    • B-cells: 0.06 - 0.66 x 109/l
    • T-cells: 0.77 - 2.68 x 109/l
      • CD4+: 0.53 - 1.76 x 109/l
      • CD8+: 0.30 - 1.03 x 109/l
    • NK cells: 0.20 - 0.40 x 109/l

Platelets

  • 140 - 440 x 109/l
    • not a cell, a cell fragment.
1. Mononuclear Phagocytic System  
Mononuclear Phagocytic System (MPS, also called Lymphoreticular System or Reticuloendothelial System, RES)
Monocyte 01.jpg Liver- Kupffer cell and reticular fibre.jpg
Circulating monocytes of peripheral blood.
  • monocytes entering the connective tissue differentiate into macrophages)
Non-circulating (fixed) tissue macrophages (MΦ)
2. Lymphoid System  
Adaptive immunity functional cells are the lymphocytes (B, T, NK) and dendritic cells (process antigen and present it on their surface, monocyte precursor derived).
  1. Antibody-mediated - B Lymphocyte (B cell) when secreting antibody = plasma cell - develop in bone marrow
  2. Cell-mediated - T Lymphocytes (T cell) form memory cell, Cytotoxic T cells, T helper cell - develop in thymus


Lymphocyte 01.jpg Lymphocyte 02.jpg

B Cell Development Germinal Centres
  • Bone marrow
  • blood
  • Lymph node, nodule
  • Lymphatic vessel
  • Bone marrow
  • Bone Marrow
  • Medullary cords contain plasma cells
Plasma cell clockface nucleus 01.jpg Plasma cells
  • Activated B cell, plasma B cells, plasmocytes, effector B cells and B cell that is secreting antibody.
  • secrete antibody directly into blood for distribution to all body
  • in local extrafollicular sites are short lived 2–4 days
  • longer-lived plasma cells in bone marrow 3 weeks to 3 months+
  • "clockface" nucleus
    • Nucleus has darker (heterochromatin) regions around periphery of nucleus separated by lighter (euchromatin) regions.


Lymphocyte Electron Micrographs  
Histologically, there is little difference in appearance between T and B lymphocytes until activated.

Lymphocyte Circulation

  • Microbial antigens are carried into a lymph node by dendritic cells, which enter via afferent lymphatic vessels draining an infected tissue.
  • T and B cells enter the lymph node via an artery and migrate out of the bloodstream through postcapillary venules.
    • Unless they encounter their antigen, the T and B cells leave the lymph node via efferent lymphatic vessels, which eventually join the thoracic duct.
  • The thoracic duct empties into a large vein carrying blood to the heart.
  • A typical circulation cycle takes about 12–24 hours.


Links: MBoC Chapter 24 - The Adaptive Immune System | MBoC Figure 24-14. The path followed by lymphocytes as they continuously circulate between the lymph and blood | Immunobiology


Diffuse Lymphatic Tissue

Diffuse Lymphatic Tissue Locations
respiratory passage, alimentary canal, ocular surface, and urogenital tract.
  • MALT - Mucosa Associated Lymphoid Tissue
    • MALT - initiates immune responses to specific antigens encountered along all mucosal surfaces.
    • NALT - Nasal Associated Lymphoid Tissue
    • BALT - Bronchus Associated Lymphoid Tissue
    • GALT - Gut Associated Lymphatic Tissue
  • Not enclosed by a connective tissue capsule
  • Located in subepithelial tissue - lamina propria
  • Diffuse lymphatic tissue + nodules
  • Reactive - enlarge when activated (by antigen)

Lymphocytes

  • travel to nodes and back again
  • proliferation and differentiation

Gastrointestinal Tract

  • Oropharynx - Tonsils
  • Distal small intestine (ilieum) - Peyer’s Patches
  • Appendix, cecum
Lymphatic-system-tonsil-MALT.jpg
Waldeyer’s ring - Mucosal Associated Lymphoid Tissue 
Waldeyer’s ring - oral adenoid tissue

Anatomical location - Palatine (tonsils), Lingual and Pharyngeal ( adenoids )

  • anterior - lingual tonsil formed by the submucous adenoid collections.
  • lateral - palatine tonsils and adenoid collections near the auditory tubes.
  • posterior - pharyngeal tonsil on the posterior wall of the pharynx.
  • between main masses are smaller collections of adenoid tissue.
Oesophagus MALT.jpg
Tonsils  
Palatine Tonsils
  • the "tonsils", lateral wall of oropharynx
  • covered by stratified squamous epithelium
  • numerous crypts (10-20) in-folds of surface epithelium

Tonsilar Crypt (crypt) - palatine tonsil squamous epithelium infold, with intraepithelial passages containing non-epithelial cells. Functions include: PMID 7559106

  1. intimate contact between immune response effector cells
  2. facilitate transport of antigens
  3. synthesise secretory components
  4. contain a pool of immunoglobulins
  • Afferent lymph vessels - absent
  • Efferent lymph vessels - present
  • PMID 7559106
Tonsil histology 01.jpg Tonsil histology 02.jpg
Lingual Tonsils
  • lamina propria root of tongue
  • covered by stratified squamous epithelium
  • salivary glands and skeletal muscle are directly adjacent
Pharyngeal Tonsils
  • adenoids or nasopharyngeal tonsils, upper posterior part of throat
  • covered by a pseudostratified ciliated epithelium with goblet cells (respiratory epithelium)

Peyer’s Patches

Peyer's Patch  
Located in the ileum (small intestine)
Peyers patches ileocolonoscopy 01.jpg Peyer's patch 01.jpg Peyer's patch 02.jpg
Peyers patches (ileocolonoscopy) Peyer's Patch (histology) Microfold cells or M-cells
(transport gut lumen organisms and particles to immune cells across the epithelial barrier).

Intestinal IgA responses synthesis/secretion.

About Peyer's Patch
External Links Notice - The dynamic nature of the internet may mean that some of these listed links may no longer function. If the link no longer works search the web with the link text or name. Links to any external commercial sites are provided for information purposes only and should never be considered an endorsement. UNSW Embryology is provided as an educational resource with no clinical information or commercial affiliation.

Lymph Nodes

Lymph Node Anatomy

Lymph Node Anatomy  
  • Location throughout the entire body - concentrated in axilla, groin, lung, gastrointestinal tract mesenteries
  • Small (1 mm - 2 cm) encapsulated organ (diffuse lymphoid tissue - no capsule)
  • Antigen transformed lymphocytes from the blood
  • In lymph vessel pathways “filter” lymph
    • Afferent - towards node (A - arrives at the node)
    • Efferent - away from node (E - exits the node)

Gastrointestinal tract intestine immune cartoon 01.jpg

Mesenteric lymph nodes

Lymphatic-system-overview.jpg

Lymph Node Functions

Lymph Node Functions  
  • In lymph vessel pathways “filter” (surveillance) lymph
  • Immune - detect infections from peripheral tissues
    • skin, respiratory tract, gastrointestinal tract, etc.
  • secondary lymphoid organ
  • return extracellular fluid to circulation
Lymph node structure.jpg

Lymph Node Structure

Lymph Node Structure  
Lymph node cartoon.jpg

Simplified structure

Lymph node cartoon 02.jpg

Lymphocyte (T and B) Traffic

  1. Enter from high endothelial venules (HEVs also called post-capillary venules)
  2. Spend 8 to 24 h in the lymph node interstitium.
  3. Enter a network of medullary sinuses.
  4. Drain from sinuses into efferent lymphatic vessels.
Lymph node structure 02.jpg Lymph pathway
  1. Afferent vessel
  2. Subcapsular sinus
  3. Paratrabecular sinus
  4. Medullary sinus
  5. Efferent vessel

Watch T and B Lymphocytes Move 

Mouse adult lymph node 07.jpg
 ‎‎Lymph Node 7
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Mouse adult lymph node 08.jpg
 ‎‎Lymph Node 8
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Lymph node cartoon 01.jpg

Lymph Node Histology

Lymph Node Histology  
Lymph node cartoon 03.jpg

Connective Tissue

  • Capsule - dense connective tissue (irregular CT, some adipocytes))
  • Trabeculae - dense connective tissue
  • Reticular Tissue - Reticular cells and fibers, supporting meshwork (collagen type III)
    • Reticular cell produces reticular fibers (collagen type III) and surrounds the fibers with its cytoplasm
    • reticular fibres can also be produced by fibroblasts
Subcapsular Sinus Follicle Germinal Centre
Lymph node histology 01.jpg

(marginal sinus, continuation of trabecular sinus)

Lymph node histology 02.jpg Lymph node histology 03.jpg
Medullary Cords and Sinuses High Endothelial Venues Macrophages
Lymph node histology 04.jpg Lymph node histology 05.jpg Lymph node histology 06.jpg


Lymph Node Cartoons: Detailed structure | Cartoon with Histology | Lymphocyte traffic | Simple structure | Simple node anatomy | Wiki node image | Internal structure | Mesenteric lymph node | Histology | Gallery | Lymph Node Development

Links: Immunobiology - Figure 1.8. Organization of a lymph node | Figure - Germinal centre development in lymph nodes | Figure - Vascular-Stromal Compartment

Thymus

Thymus Anatomy

Thymus Anatomy
Thymus cartoon.jpg Gray1178.jpg
adult thymus - bilobed, superior mediastinum, anterior to heart infant thymus - large
Thymus Involution
Fetal thymus weight growth graph.jpg Overall Size Changes with age
  • birth 10-15 g
  • puberty 30-40 g
  • after puberty - involution
    • replaced by adipose tissue
  • middle-aged 10 g

Thymus Functions

Thymus Functions  
  • specialised thymus microenvironments allow the production of self-tolerant T-cells (T lymphocytes) from immature precursors.
    • immature precursors enter the thymus
    • differentiate and undergo selection by thymic epithelial cell (TEC) subtypes
    • mature release into circulation of these cells
  • destruction of cells that recognise self antigens
  • T-cells kill infected and oncogenic cells


T Cells maturation within the thymus

  1. T cell progenitors enter the thymus at the cortex/medulla border via post–capillary venules
  2. migrate toward the capsule in response to chemokine signalling.
  3. cortex - thymocytes undergo positive selection by cTECs then migrate to the medulla
  4. medulla - thymocytes are screened for reactivity to tissue-restricted self antigens expressed by mTECs.
  5. Mature T cells exit the thymus via blood or lymphatic vessels in response to a sphingosine-1-phosphate (S1P) gradient.
Thymus structure and function cartoon01.jpg
Mouse adult thymus 11.jpg

Macrophages phagocytosis of T cells

Mouse adult thymus 11.jpg
 ‎‎Thymus 1
Page | Play
T and B lymphocytes EM09.jpg

EM - T and B lymphocytes (look the same)

Thymus Structure

Thymus Structure  
Structure Overview
Thymus histology 06.jpg
  • Connective tissue capsule (thin) with numerous trabeculae (septa)
    • major blood vessels run in CT
  • Lobules containing cortex and medulla regions
    • medullary regions are continuous (connected together)
  • NOT supplied by afferent lymph vessels


Blood-Thymic Barrier

  • Blood vessels are separated from thymus cortex by epithelioreticular cells.
  • impermeable to most macromolecules.
  • Barrier layers: capillary endothelium - endothelial basal lamina- perivascular CT sheath - basal lamina of epithelioreticular cells - epithelioreticular cell sheath
Thymus Epithelioreticular cells (TEC) Macrophages Lymphocytes
  • Abundant, eosinophilic, large, ovoid and light nucleus 1-2 nucleoli
  • sheathe cortical capillaries
  • form an epitheloid layer
  • maintain microenvironment for development of T-lymphocytes in cortex (thymic epitheliocytes)
  • cortex and medulla
  • difficult to distinguish from reticular cells in (Stain - Haematoxylin Eosin)
  • remove auto-reactive T-lymphocytes
  • located in cortex and medulla
  • more numerous (denser) in cortex
  • majority are developing T-lymphocytes (= thymic lymphocytes or thymocytes)

Thymus Histology

Thymus Histology  
  • Capsule (thin) with trabecular or septa (dense connective tissue)

Thymus histology 01.jpg

Thymus histology 06.jpg

Infant thymus

Fetal thymus Young medulla Young cortex
Fetal thymus.jpg Thymus - young 01.jpg Thymus - young 02.jpg


Adult Thymus
Thymus adult.jpg
  • Cortical lymphoid tissue is replaced by adipose tissue (involution)
  • Increase in size of thymic corpuscles
  • Thymic corpuscle - (Hassall’s corpuscle) mass of concentric epithelioreticular cells.


Thymus Histology: Fetal Thymus overview | Fetal Thymus Medulla | Fetal Thymus Cortex | Adult Thymus | unlabeled fetal overview | unlabeled fetal medulla |unlabeled fetal thymic corpuscle |unlabeled fetal cortex | unlabeled adult overview | Category:Thymus | Immune System Development

Spleen

Spleen Anatomy

Spleen Anatomy
Spleen anatomy.jpg Gray1039.jpg
left hypochondriac region almost entirely surrounded by peritoneum adherent to its capsule

Spleen Functions

Spleen Functions  
  1. Immune - filters blood in much the way that the lymph nodes filter lymph.
    1. Lymphocytes in the spleen react to pathogens in the blood and attempt to destroy them.
    2. Macrophages then engulf the resulting debris, the damaged cells, and the other large particles.
  2. Red Blood Cell Removal - spleen (and liver) removes old and damaged erythrocytes from the circulating blood.
  3. Blood Reservoir - The sinuses in the spleen also act as a reservoir for blood. In emergencies (haemorrhage) smooth muscle in the vessel walls and in the capsule of the spleen contracts, squeezes blood out of the spleen into the general circulation.

Spleen Structure

Spleen Structure  
Spleen structure cartoon 01.jpg
  • afferent splenic artery branches into central arterioles, which are sheathed by white pulp areas.
  • white pulp areas consist of the T-cell zone (also known as the periarteriolar lymphoid sheath, PALS), arterioles and B-cell follicles.
  • arterioles end in cords in the red pulp, from where the blood runs into venous sinuses that collect into the efferent splenic vein.
  • larger arteries and veins run together in connective-tissue trabeculae, which are continuous with the capsule that surrounds the spleen.

Spleen structure cartoon 02.jpg

Red pulp

Spleen Histology

Spleen Histology  
  • Capsule with trabeculae (dense connective tissue)
  • Reticular fibroblasts - reticular fibres (Type III collagen)

Spleen histology 06.jpg

White Pulp Red Pulp
  • lymph follicle
  • germinal center
  • central artery
    • periarterial lymphoid sheath (PALS)
  • splenic cords
    • macrophages
    • reticular fibroblasts
  • splenic sinuses
    • endothelium (discontinuous structure)
Overview - red and white pulp Overview - blood vessels Red pulp
Spleen histology 01.jpg Spleen histology 02.jpg Spleen histology 03.jpg

Reticular Fibers (type III collagen) act as supporting meshwork (can be seen in Silver stained preparations)

Spleen histology 05.jpg Spleen histology 04.jpg
Spleen Development: SH Lecture Spleen | SH Adult Histology | Overview Red and White Pulp | Overview Red and White Pulp | Cords and Sinuses | Reticular Fibre overview | Reticular Fibre detail | unlabeled red and white pulp | unlabeled red pulp and macrophages | unlabeled white pulp germinal centre | unlabeled reticular fibre | unlabeled white pulp reticular | unlabeled red pulp reticular | Structure cartoon | Cartoon and stain | Category:Spleen | Histology Stains | Immune System Development


Additional Information

Additional Information - Content shown under this heading is not part of the material covered in this class. It is provided for those students who would like to know about some concepts or current research in topics related to the current class page.
Janeway’s Immunobiology  
Mark Hill.jpg
A useful resource textbook for further reading on Lymphatic Structure and Organs is Immunobiology 5th edition The Immune System in Health and Disease Charles A Janeway, Jr, Paul Travers, Mark Walport, and Mark J Shlomchik. Open links in a new tab if you wish to refer back to this lecture page.

I have included some links in this table below to specific notes and there is also available a complete list of contents.

External Links Notice - The dynamic nature of the internet may mean that some of these listed links may no longer function. If the link no longer works search the web with the link text or name. Links to any external commercial sites are provided for information purposes only and should never be considered an endorsement. UNSW Embryology is provided as an educational resource with no clinical information or commercial affiliation.

Immunobiology 5th edition The Immune System in Health and Disease Charles A Janeway, Jr, Paul Travers, Mark Walport, and Mark J Shlomchik.

Part I. An Introduction to Immunobiology and Innate Immunity Chapter 1. Basic Concepts in Immunology

Part III. The Development of Mature Lymphocyte Receptor Repertoires Chapter 7. The Development and Survival of Lymphocytes


SHsmall.jpg

SH Practical - Lymphatic Structure and Organs associated practical support page. Note that virtual slides will be used in the associated practical class and this linked page is provided for student self-directed learning of concepts from the virtual slides.

Lymphatic cartoon links: Overview | Tonsil | Tonsil and MALT | Thymus | Spleen | Bone marrow | Lecture - Lymphatics | Immune System Development
Lymph Node Subcapsular Space Functions?  
The subcapsular region is not only the initial entry site for lymph flow into the node, but has also been shown to have important immune functions.

Macrophages

Subcapsular sinus macrophages clear lymph-borne viruses and present them to antiviral B cells.[1] This has also been recently demonstrated in the mouse model.[2]

Memory B cells

Memory B cells have also been shown to be reactivated in subcapsular proliferative foci of lymph nodes.[3]

  1. Junt T, Moseman EA, Iannacone M, Massberg S, Lang PA, Boes M, Fink K, Henrickson SE, Shayakhmetov DM, Di Paolo NC, van Rooijen N, Mempel TR, Whelan SP & von Andrian UH. (2007). Subcapsular sinus macrophages in lymph nodes clear lymph-borne viruses and present them to antiviral B cells. Nature , 450, 110-4. PMID: 17934446 DOI.
  2. Moran I, Grootveld AK, Nguyen A & Phan TG. (2019). Subcapsular Sinus Macrophages: The Seat of Innate and Adaptive Memory in Murine Lymph Nodes. Trends Immunol. , 40, 35-48. PMID: 30502023 DOI.
  3. Moran I, Nguyen A, Khoo WH, Butt D, Bourne K, Young C, Hermes JR, Biro M, Gracie G, Ma CS, Munier CML, Luciani F, Zaunders J, Parker A, Kelleher AD, Tangye SG, Croucher PI, Brink R, Read MN & Phan TG. (2018). Memory B cells are reactivated in subcapsular proliferative foci of lymph nodes. Nat Commun , 9, 3372. PMID: 30135429 DOI.
Mouse Lymphocyte Motility Movies  
Mouse adult lymph node 01.jpg
 ‎‎Lymph Node 1
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Mouse adult lymph node 02.jpg
 ‎‎Lymph Node 2
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Mouse adult lymph node 03.jpg
 ‎‎Lymph Node 3
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Mouse adult lymph node 04.jpg
 ‎‎Lymph Node 4
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Mouse adult lymph node 05.jpg
 ‎‎Lymph Node 5
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Mouse adult lymph node 06.jpg
 ‎‎Lymph Node 6
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Mouse adult lymph node 07.jpg
 ‎‎Lymph Node 7
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Mouse adult lymph node 08.jpg
 ‎‎Lymph Node 8
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Mouse Immune Movies: Transendothelial migration | T cell zone | Medullary sinus | Sinus endothelial barrier | Bi-directional traffic | cross the sinus endothelial barrier | T and B cell motility | T and B cell coupling
Additional Images  

Nature Immunology - Videos

Nature Immunology - These are short (5-10 min) animations showing how the immune system monitors the epithelial and environment interface at different anatomical locations.

YouTube Links


Government Sources

These information pages provide general information to the public. See how the biology concepts have been simplified to make them more understandable.

USA

Australia

Blood Cells  
Mark Hill.jpg
Blood cell information shown in the table below is also additional information for reference purposes.

Blood Cell Numbers

The adult ranges of cells / 1 litre (l), total blood volume is about 4.7 to 5 litres. Blood Development | Blood Histology

Red Blood Cells

  • Male: 4.32 - 5.66 x 1012/l
  • Female: 3.88 - 4.99 x 1012/l

Leukocytes (white blood cells)

  • Male: 3.7 - 9.5 x 109/l
  • Female: 3.9 - 11.1 x 109/l

Granulocytes

  • 1.8 - 8.9 x 109/l
    • Neutrophils: 1.5 - 7.4 x 109/l
    • Eosinophils: 0.02 - 0.67 x 109/l
    • Basophils: 0 - 0.13 x 109/l

Non-Granulocytes

  • Monocytes 0.21 - 0.92 x 109/l

Lymphocytes

  • 1.1 - 3.5 x 109/l
    • B-cells: 0.06 - 0.66 x 109/l
    • T-cells: 0.77 - 2.68 x 109/l
      • CD4+: 0.53 - 1.76 x 109/l
      • CD8+: 0.30 - 1.03 x 109/l
    • NK cells: 0.20 - 0.40 x 109/l

Platelets

  • 140 - 440 x 109/l
    • not a cell, a cell fragment.
Anatomy of the Human Body (1918) - Lymphatics  
Mark Hill.jpg
Anatomy of the Human Body Gray (1918) Historic anatomy is good, though there are there are some functional inaccuracies.
Textbook Links: MBoC Figure 24-6. The development and activation of T and B cells | [http://www.ncbi.nlm.nih.gov/books/NBK26921/figure/A4430/ Figure 24-7. Electron micrographs of nonactivated and activated lymphocytes | Immunobiology - Figure 1.9. Organization of the lymphoid tissues of the spleen

Terms

A few key terms associated with the lymphoid system.

Immune Development

  • adenoid - (Greek " +-oeides = in form of) in the form of a gland, glandular; the pharyngeal tonsil.
  • afferent lymph - vessel carrying lymph towards a node containing antigen-presenting cells, antigen, effector and memory T cells, and regulatory T cells.
  • acquired immune deficiency syndrome - (AIDS) note this is now better described as "advanced HIV disease", decrease in the number of CD4 T cells. (More? Immunobiology - AIDS)
  • anastomose - joining of two tubes or structures together.
  • Antibody mediated immunity - the immune function of plasma cells (active B lymphocytes) secreting antibody which binds antigen.
  • antibodies - mammals have five classes (IgA, IgD, IgE, IgG, and IgM)
  • antigen - any substance that is recognised by the immune system and stimulates antibody production.
  • appendix - is a gut-associated lymphoid tissue (GALT) located at the beginning of the colon. The anatomy is as a finger-like structure that arises from the cecum. The length (2.5-13 cm) is longer in both infants and children and also has more abundant lymphatic tissue in early life. The wall structure is similar to the small intestine (though with no villi), nor plicae circularis. Lymph nodules surround the lumen of the gastrointestinal tract and extend from the mucosa into the submucosa.
  • B lymphocyte - (B cell, B-cell)
  • BALT - (Bronchus Associated Lymphoid Tissue) immune tissue associated with the respiratory tract.
  • band cell - (band neutrophil or stab cell) immature neutrophil seen in bone marrow smear, a cell undergoing granulopoiesis, derived from a metamyelocyte, and leading to a mature granulocyte. Also occasionally seen in circulating blood.
  • bone marrow sinusoid - endothelial cells and no supporting cells vascular space supplied by arteriole and capillary vessels, interconnected by inter-sinusoidal capillaries, spanning throughout the bone marrow. Radially distributed around the draining central sinus (about 100 µm in diameter). Bone marrow sinusoids are unique and are not comparable with regular veins.
  • cecum - (caecum, Latin, caecus = "blind") within the gastrointestinal tract a pouch that connects the ileum with the ascending colon of the large intestine.
  • cell - has a specific cell biology definition, but is often used instead of "lymphocyte" when describing B and T cells.
  • "clockface" - a term used to describe the appearance of plasma cell nuclei due to the clumping of the chromatin at the nucleus periphery. More clearly seen in tissue plasma cells that the bone marrow smear, where they are sometimes confused with the basophilic erythroblasts. Image - plasma cell
  • CD - (cluster of differentiation) identifies immunological surface markers on cells. Positive (+) generally means that the substance is expressed/identified, while negative (-) means that it is missing/not identified.
  • CD4+ - (T helper cells) refers to T lymphocytes that express CD4 (cluster of differentiation 4, a glycoprotein of the immunoglobulin superfamily) on their surface, associated with helper/inducer function. These cells can be infected by human immunodeficiency virus (HIV).
  • CD4/CD8 ratio - clinical measurement of different immune cell types (ratios between 1.5 to 2.5 are considered normal). Viral infections such as HIV, cytomegalovirus, Epstein-Barr virus, and influenza virus, associated with an inversion of the ratio.
  • CD8+ - (cytotoxic T cells) refers to T lymphocytes that express CD8 (glycoprotein of the immunoglobulin superfamily) on their surface, associated with cytotoxic/suppressor activity.
  • "clockface" - a term used to describe the appearance of plasma cell nuclei due to the clumping of the chromatin at the nucleus periphery. More clearly seen in tissue plasma cells that the bone marrow smear, where they are sometimes confused with the basophilic erythroblasts.
  • cords of Billroth - spleen cellular columns located in red pulp. surrounded by splenic sinusoids. Cords contain reticular cells, macrophages, lymphocytes, plasma cells and erythrocytes.
  • cortex - outer layer, used in association with medulla (innner layer or core) a general description that can be applied to describing an organ with a layered structure.
  • cortical Thymic Epithelial Cell - (cTEC, types I - IV) support and antigen presenting cells located in the cortex regions of the thymus required for positive and negative selection of maturing T cells. See also medullary epithelial cell.
  • crypt - (tonsil crypt) tonsil squamous epithelium infold, with intraepithelial passages containing non-epithelial cells. Functions include: intimate contact between immune response effector cells, facilitate transport of antigens, synthesise secretory components, and contain a pool of immunoglobulins. PMID 7559106
  • dendritic cell - (DC, antigen-presenting cell, APC) cells that present antigens and induce a primary immune response in resting naïve T lymphocytes. Originate from the same common progenitor as monocytes (PMID 20193011). In 2011 Ralph M. Steinman received half the Nobel Prize half of the award to to Ralph M. Steinman for his discovery of the dendritic cell and its role in adaptive immunity.
  • Effector cells - the immune functioning (active) B and T lymphocytes.
  • Efferent lymph - vessel carrying lymph away from a node.
  • fibroblastic reticular cell - (FRC) specialized myofibroblasts that form the structural mesenchymal network "sponge" within lymphoid tissue that regulate immune cell migration, activation, and survival. Immune T cells, B cells, dendritic cells (DCs), plasma cells and macrophages move and interact.
  • follicular dendritic cell - (FDC) in B cell follicles of secondary lymphoid organs, cells interspersed within the stromal cell network function: Primary - help B cells to cluster. Secondary - in GC long-term retention of intact antigen and support B cell survival.
  • GALT - Gut Associated Lymphatic Tissue consisting of Peyer’s patches, isolated lymphoid follicles and mesenteric lymph nodes.
  • germinal centre - (GC) centre of B cell follicles of secondary lymphoid organs, where antigen-activated B-cell clones expand and undergo immunoglobulin gene hypermutation and selection.
  • haemopoiesis (hemopoiesis) formation of blood cells.
  • high endothelial venule - (HEV) the specialised post-capillary venous region that enables blood lymphocytes and pre-dendritic cells to enter a lymph node. The endothelial cells express ligands that bind lymphocytes, aiding their adhesion and subsequent transmigration into the lymph node. With inflammation, monocytes and NK cells can also enter here.
  • humoral immune response - production of antibody by plasma cells derived from B lymphocytes (B cells).
  • IEL - Intraepithelial Lymphocyte are T lymphocytes located in the gastrointestinal tract epithelium. Natural IELs (previously ‘type b’ IELs) acquire activated phenotype during development in the thymus in the presence of self antigens. Induced IELs (previously ‘type a’ IELs) progeny of conventional T cells activated post-thymically in response to peripheral antigens.
  • IgA - the main class of antibody released at mucosal surfaces and in secretions (saliva, tears, milk, and respiratory and intestinal secretions) and the most abundantly produced antibody (70%). PMID 22566964
  • IgD - the immunoglobulin B cell starts to produce as a cell-surface molecule after leaving the bone marrow.
  • IgE - bind Fc receptors (surface of mast cells in tissues and basophils in the blood) release of potent pro inflammatory molecules mediators of allergic reactions.
  • IgG - the major class of immunoglobulin in the blood.
  • IgM - the first class of antibody made by a developing B cell, which may switch to making other classes of antibody.
  • immunoglobulin - (antibody, Ab) protein produced by plasma cells.
  • immunosenescence - in ageing and disease, refers to a weaker immune responses producing a progressive deterioration and increased susceptibility to infectious diseases, neoplasia, and autoimmune diseases.
  • innate lymphoid cells - (ILCs) subset of lymphocytes that lack antigen-specific receptors, are located in peripheral tissues and abundant at barrier surfaces, decrease in number with age. PMID 29924974
  • Kupffer cells - stellate macrophage cells located in the liver sinusoids, named after Karl Wilhelm von Kupffer (1829 - 1902) a German anatomist who originally identified these cells. (More? Liver Development)
  • lacteal - term used to describe the lymphatic vessels of the small intestine.
  • lamina propria - a layer of loose connective tissue found underneath an epithelium, together with the epithelium described as mucosa.
  • Langerhans cell - (LC, dendritic cell) Antigen-presenting immune cell found mainly in the basal/suprabasal layers of adult skin and mucosa. Cells lie in the basal/suprabasal layers of stratified epidermal and mucosal tissues. First in the innate antiviral immune defines and can migrate to lymph nodes and induce a T cell–mediated adaptive immune response. (More? Integumentary | Immune System Development)
  • Leukocyte - (Greek, lukos = clear, white) white blood cell.
  • lingual - related to the tongue, as in lingual tonsil, forms part of Waldeyer’s ring.
  • lymph node - connective tissue encapsulated lymphoid organ (1mm - 2cm in size), positioned in the pathway of lymph vessels. (More? Lymph Node Development)
  • lymphangion - the functional unit of a lymph vessel that lies between two semilunar (half moon-shaped) valves.
  • lymphangiogenesis - formation of new lymph vessels from pre-existing lymphatic structures. During embryogenesis and in adult tissues as reaction to inflammation or injury.
  • M cell - (microfold cell) found in the follicle-associated epithelium of the Peyer's patch. Function to transport gut lumen organisms and particles to immune cells across the epithelial barrier.
  • MALT - Mucosa Associated Lymphoid Tissue.
  • medulla - inner layer or core, used in association with cortex (outer layer) a general description that can be applied to describing an organ with a layered structure.
  • medullary Thymic Epithelial Cell - (mTEC, types I-VII) support and antigen presenting cells located in the medullary regions of the thymus, required for central tolerance (negative selection) of maturing T cells (PMID 11375064). See also cortical thymic epithelial cell.
  • Memory Cell - effector T cell (lymphocyte)
  • Mononuclear Phagocytic System - (MPS, Lymphoreticular System, Reticuloendothelial System, RES) Consists of circulating monocytes in the peripheral blood and non-circulating (fixed) tissue macrophages (MΦ) located in tissues and organs.
  • NAVL - (naval) mnemonic to remember the neurovascular bundle components Nerve Artery Vein Lymph found travelling together within organs and tissues.
  • negative selection - T cells bearing autoreactive T cell antigen receptors (TCRs) are eliminated during their development in the thymus, protects against autoimmunity.
  • normoblast - seen in bone marrow smear, a developing erythroblast (red blood cell) that still retains a nucleus.
  • nude mice - (nu/nu) mice which are congenitally hairless and athymic, therefore they do not reject tissue and tumor grafts.
  • PALS - acronym for PeriArterial Lymphoid Sheath in the spleen white pulp.
  • parenchyma - (Greek = enkeim "to pour in") cells forming the functional cells of an organ or tissue. These cells carry out the function of the organ at a cellular level, and are not the structural cells, connective tissue, extracellular matrix (stromal).
  • periarterial lymphoid sheath - (PALS) in the spleen the white pulp that surrounds the central arteries. (T-lymphocytes,macrophages and plasma cells)
  • pharyngeal pouch III - origin of endodermal component of the thymus (also formed from neural crest). Pharyngeal arches
  • Plasma Cell - active B cell (lymphocyte) which is secreting antibody. Located in either bone marrow or peripheral lymphoid tissues, these cells have and increased cytoplasmic volume (due to increase rough endoplasmic reticulum) in comparison to the inactive (non-secreting) lymphocyte.
  • primary follicle - follicle that does not contain germinal centre, secondary follicles do germinal centre.
  • red pulp - spleen region, organized as cell cords (splenic cords, cords of Billroth) and vascular sinuses.
  • regulatory T cells - (Tregs) maintain self tolerance and suppress pathological immune responses by control of immune response to non-self antigens.
  • reticular fibres - reticular cells secrete this extracellular matrix protein, composed of type III collagen.
  • right lymphatic duct - drains most of the right upper quadrant. See also thoracic duct.
  • secondary follicle - contain germinal centre, primary follicle does not contain germinal centre.
  • sentinel lymph node - the hypothetical first lymph node or group of nodes reached by metastasizing cancer cells from a primary tumour.
  • sinus - a larger vessel or space usually curved that may contain air, blood, or lymph. e.g. splenic medullary sinus, lymph node medullary sinus, sub-capsular sinus, trabecular sinus.
  • sinusoid - a tiny vessel with a tortuous path and many connections to similar vessels. e.g. hepatic and bone marrow sinusoids.
  • splenic capillary sheaths - in spleen around capillary endothelium and consist of three main cell types: CD271+ stromal capillary sheath cells, CD68+CD163− macrophages and recirculating B-lymphocytes. Sheaths may; 1. allow interaction among sheath macrophages and B-lymphocytes, 2. attract recirculating B-lymphocytes from the open circulation of the red pulp to start migration into white pulp follicles. 30356180
  • splenic sinusoids - enlarged splenic spaces located in red pulp and surrounding cords of Billroth.
  • sphingosine-1-phosphate - (S1P) sphingolipid secreted into the extracellular space establishing a gradient acting through G protein-coupled receptors to attract lymphocytes out of lymphoid organs (lymph node, thymus, spleen) into the circulation.
  • stroma - (Greek = "a cover, table-cloth, bedding") tissue forming the framework/support of an organ or tissue. That is the structural cells which form connective tissue and secrete extracellular matrix, rather than the functional cells (parenchymal). All organs can therefore be functionally divided into these 2 components, stromal/parenchymal.
  • Subcapsular sinus (=marginal sinus) space lying under the connective tissue capsule which receives lymph from afferent lymphatic vessels.
  • T cell - (T-cell, T lymphocyte) named after thymus, where they develop, the active cell is responsible for cell-mediated immunity (killer T cells and helper T cells). Cells express T-cell receptor on surface and directly kill virally or bacterially infected cells. These cells can themselves be infected by HIV. (More? Electron micrographs of nonactivate and activated lymphocytes)
  • TEC - (Thymic Epithelial Cell) thymus support and antigen presenting cells further divided anatomically and functionally into medullary TEC (mTEC, types I-VII, for central tolerance) and cortical epithelial cell (cTEC, types I-IV, positive and negative selection) populations (see PMID 28800929 PMID 30308217).
  • T cell activation - (T lymphocyte activation)The activation process begins with T-cells searching for and encountering antigen-bearing dendritic cells within lymph nodes.
  • thoracic duct - (TD) largest and main lymphatic vessel, drains the lower body including the extremities and abdomen. Intra-thoracic tributaries include: intercostal, mediastinal, and bronchomediastinal trunks.


  • Thymic corpuscle - (Hassall's corpuscle) a mass of concentric epithelioreticular cells found in the thymus. The number present and size tend to increase with thymus age. (see classical description of Hammar, J. A. 1903 Zur Histogenese und Involution der Thymusdriise. Anat. Anz., 27: 1909 Fiinfzig Jahre Thymusforschung. Ergebn. Anat. Entwickl-gesch. 19: 1-274.)
  • thymic epitheliocytes - reticular cells located in the thymus cortex that ensheathe the cortical capillaries, creating and maintain the microenvironment necessary for the development of T-lymphocytes in the cortex.
  • T helper cells - (helper T-cells) (Th cells, CD4+) refers to T lymphocytes that when mature express CD4 (glycoprotein of the immunoglobulin superfamily) on their surface.
  • T lymphocyte - (T cell, T-cell) regulate cell-mediated immunity.
  • thymus - an immune/endocrine (thymic hormone, thymosins) organ involved in the maturation (differentiation) of T lymphocytes (T-cells).
  • tonsils - lymph nodules embedded in the mucus membranes located at the back of the mouth and top of the throat. The overlying epithelium helps identify the location.
  • tonsillitis - a common bacterial infection of the palatine tonsils, occurring mostly in children and young adults and can also become recurrent tonsillitis.
  • vermiform appendix - see appendix, anatomical region containing gut-associated lymphoid tissue located within the gastrointestinal tract at the beginning of the colon. The anatomy is as a finger-like structure that arises from the cecum. The length (2.5-13 cm) is longer in both infants and children and also has more abundant lymphatic tissue in early life. The wall structure is similar to the small intestine (though with no villi), nor plicae circularis. Lymph nodules surround the lumen of the gastrointestinal tract and extend from the mucosa into the submucosa.
  • VDJ recombination - (variable, diversity and joining gene segments) genetic recombination event that occurs in immune cell maturation in primary lymphoid organs, B cells ((bone marrow) and T cells (thymus).
  • Waldeyer’s ring - ring of lymphoid tissue in the pharyngeal wall: palatine tonsils, nasopharyngeal tonsil (adenoid) and lingual tonsil. First described in 1884 by von Waldeyer-Hartz.
  • white pulp - (Malpighian follicles, Malpighian bodies of the spleen, white nodules, splenic lymphoid nodules) spleen lymphoid region, organized as lymphoid sheaths with both T-cell and B-cell compartments, around the branching arterial vessels (resembles lymph node structure).


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Cite this page: Hill, M.A. (2019, October 18) Embryology SH Lecture - Lymphatic Structure and Organs. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/SH_Lecture_-_Lymphatic_Structure_and_Organs

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© Dr Mark Hill 2019, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G