Sandbox: Difference between revisions

From Embryology
mNo edit summary
No edit summary
 
(47 intermediate revisions by 2 users not shown)
Line 1: Line 1:
''A draft page designed to be used only for testing.''
{{Header}}
 
[[File:Amniocentesis.jpg|300px|right]]
 
==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).
'''How and why do things go wrong in development?'''
 
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.
 
{|
|-
! Structure
! Function
|-
|
# '''Cells''' - blood cells (parenchyma), connective tissue (stroma)
# '''Vessels''' - lymphatic vessels
# '''Diffuse''' - (extra-nodal tissue) nodules, Mucosal Associated Lymphoid Tissues (MALT)
# '''Nodes''' - (historic, "glands")
# '''Organs''' - thymus, spleen
| valign="top"|
# '''Immune''' - “monitor” of body surfaces, internal fluids
# '''Extracellular fluid''' - returns interstitial fluid to circulation
# '''Gastrointestinal tract''' - carries fat and fat-soluble vitamins
|}
 
[[File:Lymphatic-system-overview.jpg|600px|Lymphatic system]]
 
 
{| class="wikitable collapsible collapsed"
! Textbook References
|-
| {{Embryo citation}}
* [[Media:SH Lecture 2013 - Lymphatic Structure and Organs.pdf|2013 Lecture PDF 15 pages, 1.4 Mb]]
* [[SH_Practical_-_Lymphatic_Structure_and_Organs|SH Laboratory Support]] | [[Media:AIDS_related_lymphoma_movie.mp4|Movie - AIDS related lymphoma]]
* Additional background information:
 
{{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]
|-
| '''Histology and Cell Biology''' - A.L. Kiersenbaum (2001) Chapter 6: Blood,  Chapter 10: Immune-Lymphatic
|-
|}
 
 
==Cells==
 
[[File:Hematopoietic_and_stromal_cell_differentiation.jpg]]
 
 
Two Blood Cell Systems
# '''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 Organs
* Central  - Lymphocytes develop from precursor cells in bone marrow. (see blood marrow image)
* Peripheral - Lymphocytes respond to antigen lymph nodes or spleen.
 
 
{| class="wikitable collapsible collapsed"
! 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 Number Table}}
|}
 
===1. Mononuclear Phagocytic System===
 
Mononuclear Phagocytic System (MPS, also called Lymphoreticular System or Reticuloendothelial System, RES)
{|
| [[File:Monocyte 01.jpg|400px]]
| [[File:Liver- Kupffer cell and reticular fibre.jpg|400px]]
|-
| Circulating '''monocytes''' of peripheral blood.
* monocytes entering the connective tissue differentiate into '''macrophages''')
| Non-circulating (fixed) tissue '''macrophages''' (MΦ)
* found throughout the body (Liver (Kuffler cells), spleen and other tissues.
|}
 
===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).
 
# '''Antibody-mediated''' - B Lymphocyte secreting antibody = '''Plasma Cell'''
# '''Cell-mediated''' - T Lymphocytes form '''memory cell''', Cytotoxic T cells, T helper cell
 
 
[[File:lymphocyte 01.jpg|400px]] [[File:Lymphocyte_02.jpg|400px]]
 
{|
| '''B Cell Development'''
| '''Germinal Centres'''
|-
| valign=top|
* Bone marrow
* blood
* Lymph node, nodule
* Lymphatic vessel
* Bone marrow
| valign=top|
* Bone Marrow
* Medullary cords contain plasma cells
|}
 
{|
| [[File:Plasma_cell_clockface_nucleus_01.jpg|400px]]
| valign=top|'''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.
|}
 
 
{| class="wikitable collapsible collapsed"
!  Lymphocyte Electron Micrographs
|-
| Histologically, there is little difference in appearance between T and B lymphocytes until activated.
 
<gallery>
File:T and B lymphocytes EM10.jpg|T and B Lymphocyte
File:T_and_B_lymphocytes_EM09.jpg|T and B Lymphocyte
File:Plasma_cell_EM06.jpg|Plasma cell (B)
File:T2_lymphocyte_EM13.jpg|Cytotoxic (T)
</gallery>
|}
 
===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:''' [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==
 
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_001.jpg]]
 
Jejunum lacteal (lymphatic capillary of small intestine villi,  absorbs dietary fats)
 
===Lymph Collecting Vessels===
[[File:Lymphatic_vasculature_03.jpg]]
 
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]]
 
Thoracic and right lymphatic ducts
|
 
[[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'''
* 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
 
 
===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
* Distal small intestine (ilieum) - Peyer’s Patches
* Appendix, cecum
 
===Mucosal Associated Lymphoid Tissues===
{|
| [[File:oesophagus MALT.jpg|300px]]
|
Anatomical location -  Palatine  ('''tonsils'''), Lingual  and Pharyngeal ( '''adenoids''' )
 
Ring of oral adenoid tissue:
* 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.
|}
 
===Palatine Tonsils===
 
[[File:Tonsil_histology_01.jpg|400px]] [[File:Tonsil_histology_02.jpg|400px]]
 
 
* the "tonsils", lateral wall of oropharynx
* covered by '''stratified squamous epithelium'''
* numerous crypts (10-20) infolds of surface epithelium
* Afferent lymph vessels absent
* Efferent lymph vessels are present
 
===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
 
===Peyer's Patch===
* located in the ileum
{|
| [[File:Peyer's patch 01.jpg|300px]]
| [[File:Peyer's patch 02.jpg|300px]]
|-
| Peyer's Patch, Ileum
| microfold cells or M-cells (transport gut lumen organisms and particles to immune cells across the epithelial barrier).
|}
 
{| class="wikitable collapsible collapsed"
! About Peyer's Patch
|-
| {{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.
|}
 
 
 
==Lymph Nodes==
[[File:Lymphatic-system-overview.jpg]]
 
 
* Location throughout the entire body - Concentrated in axilla, groin, mesenteries
* Encapsulated organ (1 mm - 2 cm)
* Antigen transformed lymphocytes from the blood
* In lymph vessel pathways “filter”
* Afferent- towards node
* Efferent- away from node
 
 
Lymph flow
* enters the node through '''afferent vessels'''
* filters through the '''sinuses'''
* leaves through '''efferent vessels'''
 
===Lymph Node Structure===
[[File:Lymph_node_cartoon_01.jpg|Lymph_node_cartoon_01.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 fibbers can also be produced by fibroblasts
 
<gallery>
File:Lymph node histology 01.jpg|Subcapsular Sinus (marginal sinus, continuation of trabecular sinus)
File:Lymph node histology 02.jpg|Follicle
File:Lymph node histology 03.jpg|Germinal Centre
File:Lymph node histology 04.jpg|Medullary Cords and Sinuses
File:Lymph node histology 05.jpg|High Endothelial Venules
File:Lymph_node_histology_06.jpg|Macrophages
</gallery>
 
 
{|
| Lymphocyte (T and B) Traffic
 
# 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.
| {{Lymph Node Movie 7}}
 
T and B motility
|
{{Lymph Node Movie 8}}
 
T and B interaction
|[[File:Lymph node histology 05.jpg|200px]]
 
High Endothelial Venules
|}
 
'''Links:''' [http://www.ncbi.nlm.nih.gov/books/NBK27092/figure/A47 Immunobiology - Figure 1.8. Organization of a lymph node]
 
 
==Thymus==
[[File:Lymphatic-system-thymus.jpg|600px]]
 
[[File:Thymus cartoon.jpg|thumb|Thymus]]
* 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===
 
* '''Reticular cells'''
** 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
Overall Size
* birth 10-15 g
* puberty 30-40 g, after puberty - involution
* middle-aged 10 g, replaced by adipose tissue
 
<gallery>
File:Thymus_cartoon.jpg|
File:Gray1178.jpg|Fetal thymus anatomy
File:Fetal thymus.jpg|Fetal thymus
File:Thymus - young 01.jpg‎|Young medulla
File:Thymus - young 02.jpg‎|Young cortex
</gallery>
 
===Adult Thymus===
{|
| [[File:Thymus adult.jpg|300px]]
|
 
* Cortical lymphoid tissue is replaced by adipose tissue
* Increase in size of thymic corpuscles
* '''Thymic corpuscle''' - (Hassall’s corpuscle) mass of concentric epithelioreticular cells.
 
[[File:Thymus - young 01.jpg|300px]]
 
{{Thymus Histology}}
|}
 
==Spleen==
[[File:Lymphatic-system-spleen.jpg|600px]]
 
 
===Spleen Function===
[[File:Spleen anatomy.jpg|thumb]]
[[File:Gray1039.jpg|thumb]]
# 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.
* '''Macrophages''' then engulf the resulting debris, the damaged cells, and the other large particles.
# Red Blood Cell Removal
* The spleen (and liver) removes old and damaged erythrocytes from the circulating blood.
* Like other lymphatic tissue, it produces lymphocytes, especially in response to invading pathogens.
# Blood Reservoir
* The sinuses in the spleen also act as a reservoir for blood.
** 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.
 
 
===Structure===
* Capsule, trabeculae (dense connective tissue)
* Splenic pulp white pulp, red pulp - based on appearance and cell content.
 
[[File:Spleen_histology_05.jpg|thumb|White pulp -periarterial lymphoid sheath (PALS)]]
{|
|
'''White Pulp'''
* lymphocytes surround central arteries
* as periarterial lymphoid sheath (PALS)
|
'''Red Pulp'''
* Red blood cells
* Splenic cords and sinuses
|}
 
'''Reticular Fibers''' (type III collagen) act as supporting meshwork.
 
<gallery>
File:Spleen_histology_01.jpg|Overview Red and White Pulp
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}}
 
 
 
 
==Additional Information==
 
''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:Lymphatic-system-overview.jpg|'''Lymphatic cartoon links''']]: [[:File:Lymphatic-system-overview.jpg|Overview]] | [[:File:Lymphatic-system-tonsil.jpg|Tonsil]] |  [[:File:Lymphatic-system-tonsil-MALT.jpg|Tonsil and MALT]] | [[:File:Lymphatic-system-thymus.jpg|Thymus]] | [[:File:Lymphatic-system-spleen.jpg|Spleen]] | [[:File:Lymphatic-system-bone-marrow.jpg|Bone marrow]] | [[SH_Lecture_-_Lymphatic_Structure_and_Organs|Lecture - Lymphatics]] | [[Immune System Development]]
[[Category:Human]] [[Category:Cartoon]] [[Category:Immune]] [[Category:Histology]]
 
<gallery>
File:Lymphatic-system-overview.jpg|Overview
File:Lymphatic-system-tonsil.jpg|Tonsil
File:Lymphatic-system-tonsil-MALT.jpg|Tonsil and MALT
File:Lymphatic-system-thymus.jpg|Thymus
File:Lymphatic-system-spleen.jpg|Spleen
File:Lymphatic-system-bone-marrow.jpg|Bone marrow
</gallery>
 
 
{{Lymph node cartoons}}
 
{| class="wikitable collapsible collapsed"
! colspan="4"|Mouse Lymphocyte Motility Movies
|-
| valign="bottom"|{{Lymph Node Movie 1}}
| valign="bottom"|{{Lymph Node Movie 2}}
| valign="bottom"|{{Lymph Node Movie 3}}
| valign="bottom"|{{Lymph Node Movie 4}}
|-
| valign="bottom"|{{Lymph Node Movie 5}}
| valign="bottom"|{{Lymph Node Movie 6}}
| valign="bottom"|{{Lymph Node Movie 7}}
| valign="bottom"|{{Lymph Node Movie 8}}
|-
| colspan="4"|'''Mouse Immune Movies:''' [[Mouse_Lymph_Node_Movie_1|Transendothelial migration]] | [[Mouse_Lymph_Node__Movie_2|T cell zone]] | [[Mouse_Lymph_Node__Movie_3|Medullary sinus]] | [[Mouse_Lymph_Node__Movie_4|Sinus endothelial barrier]] | [[Mouse_Lymph_Node_Movie_5|Bi-directional traffic]] | [[Mouse_Lymph_Node__Movie_6|cross the sinus endothelial barrier]] | [[Mouse_Lymph_Node__Movie_7|T and B cell motility]] | [[Mouse_Lymph_Node__Movie_8|T and B cell coupling]]
|}
 
{| class="wikitable collapsible collapsed"
!  Additional Images
|-
|
<gallery>
File:Adult_lymphatic_system.jpg|Adult lymphatic system
File:Lymph_node_cartoon.jpg|Lymph node cartoon
File:Lymph_nodes_head_neck_superficial.jpg|Lymph nodes - head neck superficial
</gallery>
|}
 
{| class="wikitable collapsible collapsed"
! Janeway’s Immunobiology
|-
| [[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]
|}
 
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]
 
 
{| class="wikitable collapsible collapsed"
! Blood Cells
|-
| [[File:Mark_Hill.jpg|left|50px]] Blood cell information shown in the table below is also additional information for reference purposes.
 
{{Blood Cell Number Table}}
|}
 
{| class="wikitable collapsible collapsed"
! Anatomy of the Human Body (1918) - Lymphatics
|-
| [[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.
 
<gallery>
File:Gray0592.jpg|592 Primary lymph sacs.
File:Gray0593.jpg|593 Lymph capillaries of the human conjunctiva.
File:Gray0594.jpg|594 Lymph capillaries from the human scrotum.
File:Gray0595.jpg|595 Lymph capillaries of the sole of the human foot.
File:Gray0596.jpg|596 Section through human tongue.
File:Gray0597.jpg|597 Lymph gland (Node).
File:Gray0598.jpg|598 Lymph gland tissue.
File:Gray0599.jpg|599 Thoracic and right lymphatic ducts.
File:Gray0600.jpg|600 Modes of origin of thoracic duct.
File:Gray0601.jpg|601 Terminal collecting trunks of right side.
File:Gray0602.jpg|602 Lymph glands of the head.
File:Gray0603.jpg|603 Lymphatics of pharynx.
File:Gray0604.jpg|604 Lymphatics of the face.
File:Gray0605.jpg|605 Lymphatics of the Tongue.
File:Gray0606.jpg|606 Lymph glands of the upper extremity.
File:Gray0607.jpg|607 Lymphatics of the mamma.
File:Gray0608.jpg|608 Lymphatic vessels of the dorsal hand surface.
File:Gray0609.jpg|609 Lymph glands of popliteal fossa.
File:Gray0610.jpg|610 Superficial lymph glands and vessels of the lower extremity.
File:Gray0611.jpg|611 Parietal lymph glands of the pelvis.
File:Gray0612.jpg|612 Iliopelvic glands.
File:Gray0613.jpg|613 Lymphatics of stomach.
File:Gray0614.jpg|614 Lymphatics of stomach.
File:Gray0615.jpg|615 Lymphatics of cecum and vermiform process.
File:Gray0616.jpg|616 Lymphatics of cecum and vermiform process.
File:Gray0617.jpg|617 Lymphatics of Colon.
File:Gray0618.jpg|618 Lymphatic of the Bladder.
File:Gray0619.jpg|619 Lymphatics of the Prostate.
File:Gray0620.jpg|620 Lymphatics of the Uterus.
File:Gray0621.jpg|621 Lymphatics of the thorax and abdomen.
File:Gray0622.jpg|622 Tracheobronchial Lymph Glands
</gallery>
|}
 
: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 ==
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])
* '''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)
* '''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.
 
 


{{Glossary}}
[[File:child smallpox.jpg|thumb|Mother with child, face and body showing smallpox scars.]]


These notes cover abnormalities that can occur during development ({{abnormal development}}) often described as {{congenital abnormalities}} or {{birth defects}}. There are many different ways that developmental abnormalities can occur the 3 major types are '''Genetic''' (inherited), '''Environmental''' (maternal) and '''Idiopathic''' (unknown, not determined) derived abnormalities. The environmental factors that cause or lead to any of these abnormalities are described as teratogens. Congenital abnormalities are classified under the system called the [[International Classification of Diseases]] ({{ICD-11}}) that version updated in 2018.


{{Footer}}
Note that genetic and environmental effects can also interact and it is this and the group, now classified as idiopathic or "unknown causes", that require further research to place them in either or both of the two real categories. Furthermore developmental organizer genes, for example Hedgehog, have been recently implicated in adult carcinogenesis.


[[Category:Immune]] [[Category:Histology]]
{{#pmid:19782018|reload}}

Latest revision as of 07:01, 31 December 2019

Embryology - 27 Jun 2024    Facebook link Pinterest link Twitter link  Expand to Translate  
Google Translate - select your language from the list shown below (this will open a new external page)

العربية | català | 中文 | 中國傳統的 | français | Deutsche | עִברִית | हिंदी | bahasa Indonesia | italiano | 日本語 | 한국어 | မြန်မာ | Pilipino | Polskie | português | ਪੰਜਾਬੀ ਦੇ | Română | русский | Español | Swahili | Svensk | ไทย | Türkçe | اردو | ייִדיש | Tiếng Việt    These external translations are automated and may not be accurate. (More? About Translations)

Amniocentesis.jpg

Introduction

How and why do things go wrong in development?

Mother with child, face and body showing smallpox scars.

These notes cover abnormalities that can occur during development (abnormal development) often described as congenital abnormalities or birth defects. There are many different ways that developmental abnormalities can occur the 3 major types are Genetic (inherited), Environmental (maternal) and Idiopathic (unknown, not determined) derived abnormalities. The environmental factors that cause or lead to any of these abnormalities are described as teratogens. Congenital abnormalities are classified under the system called the International Classification of DiseasesICD-11) that version updated in 2018.

Note that genetic and environmental effects can also interact and it is this and the group, now classified as idiopathic or "unknown causes", that require further research to place them in either or both of the two real categories. Furthermore developmental organizer genes, for example Hedgehog, have been recently implicated in adult carcinogenesis.

PubmedParser error: Pubmed did not return article data, please check the PMID or try again later. (PMID: 19782018)