Talk:Draft 2016

Blood Cells

Two Blood Cell Systems

Alimentary canal, respiratory passage and urogenital tract. 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. 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.

Mucosal Associated Lymphoid Tissues
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.

Tonsils
Palatine Tonsils 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 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). 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. Learn how the Peyer's Patches function in the Gut Mucosa immune function in this 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.

1. Mononuclear Phagocytic System

Mononuclear Phagocytic System (MPS, also called Lymphoreticular System or Reticuloendothelial System, RES)

Circulating monocytes of peripheral blood. monocytes entering the connective tissue differentiate into macrophages)	Non-circulating (fixed) tissue macrophages (MΦ) found throughout the body (Liver, Kuffer cells), spleen, nodes 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).

1. Antibody-mediated - B Lymphocyte secreting antibody = Plasma Cell
2. Cell-mediated - T Lymphocytes form memory cell, Cytotoxic T cells, T helper cell

B Cell Development	Germinal Centres
Bone marrow blood Lymph node, nodule Lymphatic vessel Bone marrow	Bone Marrow Medullary cords contain plasma cells

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. T and B Lymphocyte T and B Lymphocyte Plasma cell (B) Cytotoxic (T)

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