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WVSOM -- Histology
Immune Systems
| Question | Answer |
|---|---|
| Lymph | 10% of the tissue that is left behind. usually 1-2 quarts |
| Immune System | Maintain the fluid environment of the body by producing filtering, and conveying lymph |
| Thymus | supports the proliferation and programming of the T lymphocyte percursors |
| T lymphocytes | Cell mediated responses Assist B cells in developing humeral responses to thymus-Dependant antigens |
| B Lymphocytes | antibody-secreting plasma cells |
| Thymus 2 parts | cortex medulla |
| Cortex of Thymus | peripheral region that contains densely packed T lymphocytes suspended in a network of epithelial reticular cells. Training T cells to not go after "self" BASOPHILLIC Site of lymphoblast proliferation to produce smaller, more mature T cells |
| Medulla of Thymus | Region contains more epithelial reticular cells and fewer T lymphocytes than the cortex. MACROPHATES AND LARGE LYMPHOCYTES Eosinophillic T cells are mature and enter the circulation through post capillary venules or efferent lymphatic vessels |
| Cortical Epithelial reticular cells | Program which T cells will die and which ones will live and progress to the thymus medulla |
| Medulla contains more ____________ epithelial cells and fewer _______________ than the cortex | epithelial reticular cells; T lymphocytes |
| Blood-thymus barrier | blood supply of the thymus enters through the capsule and connective tissue septa |
| Hassall Corpuscles | formed from type VI epithelial reticular cells and found in Thymus. |
| What makes the thymus different from otehr lymph tissue | Does not check any lymph from the body. Only EFFERENTS. Can only leave the thymus. No afferent lymphatics or lymph sinuses present No lymphatic nodules present |
| EBV | only carried in saliva. B lymphocytes may also contain the virus in a state of incomplete replication When B lymphocytes become infected, they are altered permanently and undergo polyconal activation adn proliferation |
| Involution of the thymus | at puberty, the thymus begins to degenerate, beginning in the cortex |
| By old age the thymus is almost all _____________. | connective tissue |
| Lymph Node | lymphoid organs found along lymphatic vessels that filter the lymph for antigens |
| Convex surface of the Lymph Node | receives afferent lymphatic vessels |
| Concave surface | contains areterioles and efferent lymphatic vessels |
| Stroma | reticular fibers structure the cells hang on to |
| Subcapsular/cortical sinus | where lymph is dropped off to check it to make sure it is ok |
| Cortex of Lymph Node | Sinusoids Lymphoid Nodule paracortex |
| Sinusoids | endothelium lined spaces create subcapsular sinuses |
| Lymphoid nodules | B cells with some T cells and macrophages |
| Paracortex | mostly T cells |
| T cells stain | basophillic |
| Germinal Center | B Cells that are activated to turn into plasma Cells Light staining center |
| Medulla of lymph node contains | cords with reticular cells and plasma cells. Stain lighter than the cortex |
| Reed-Sternberg Cells | Look like lacuna in the lymph Diagnostic cells for Hodgkins and other lymph node disease |
| Spleen | Largest Lymphoid organ Filters blood |
| Spleen is surrounded by a | capsule |
| Spleen consists of 2 different kinds of _____________ | pulp |
| 2 kinds of pulp | White and red |
| White Pulp | Sticks with arteries Named for having white blood cells |
| Red Pulp | Disorganized Associated with Red blood cells |
| Splenic Artery | enters at the hilum thru connective tissue |
| Splenic Trabeculae arteries | Branches from the splenic artery. When they enter the splenic pulp they become central arterioles |
| PWP | Peripheral White Pulp B cells |
| PALS | T Cells |
| Divisions of the arteries follow | the white pulp |
| What makes spleen different form the other lymph tissue | no afferent lympatics or lymph sinues present No cortex or medulla Sophisticated vascular system Lymphoid tissue found in the while pulp |
| Mononucleosis and the spleen | spleen enlarges becuase it is flooded with atypical lymphocytes. Get lodged in the red pulp as well as teh capsule and trabeculae |
| Unencapsulated lymphoid nodules | unorganized Named for area it is at Groups of T cells just hanging out Found in loose connective tissue |
| GALT | Gastrointestinal Associated Lymphatic Tissue |
| 2 zones of unenecapsulated lympohoid nodules | Marginal and germinal center |
| Marginal Zone | Has memory cells |
| Germinal Center | Has B cells |
| BALT | broncial-associated lymphatic tissue |
| peyer's patches | globs of purple found in ileum setting a stage for immune response if needed |
| Adenoids | Pharyngeal Posterior wall of nasopharynx covered with ciliated pseudostratified colummnar epithelium |