Test 3 - Lymphatics Flashcards
What is the lymphatic system?
- route for excess interstitial fluid to return to blood
- allows for cells of immune system to travel, communicate, proliferate
What are the lymphatic system components?
- bone marrow
- thymus
- spleen
- lymph nodes & lymphatic nodules
- diffuse lymphatic tissue
- lymph vessels
Innate immunity
- non-specific
- pre-existing defense system that consists of chemical defense, physical barrier, phagocytic cells, and secretory substances that neutralize foreign cells
Adaptive immunity
- specific defense system
- targets invaders that evaded innate (back-up)
- two types: humoral & cellular immune
Humoral response
antibody production
Cellular immune response
targets “bad” cells for destruction by specific killer cells
Which immunity goes with which progenitor line?
adaptive -> common lymphoid progenitor
innate -> common myeloid progenitor
What are T-cells and where do they mature?
- responsible for cell-mediated immunity
- mature in thymus
What are the 4 types of T-cells?
- helper
- cytotoxic
- regulatory
- gamma
What are B-cells and where do they mature?
- reponsible for humoral response
- mature in bone marrow
What are the 2 types of B cells?
- plasma (make specific antibody)
- memory (respond to next exposure)
What is the function of a primary lymphoid organ?
where lymphocytes differentiate into immunocompetent cells
Name primary lymphoid organs.
- bone marrow (B)
- thymus (T)
What is thymic involution and why does it occur?
when the thymus starts to “deactivate” with age - around 20 the thymus becomes inactive, stops T-cell production and the organ turns into mainly adipose
Histology of the thymus.
- CT capsule that extends from trabeculae
- Lymphoepithelial organ
- Lymphocytes & epithelioreticular cells
- Has cortex, medulla, Hassall’s corpuscle
What are the secondary lymph tissues and organs and their functions? (2 fx)
- sites of initial immune response
- diffuse lymphatic tissue
- lymphatic nodules - proliferation & differentiation
- lymph node
- spleen
(all are antigen-activated)
Histology of the lymphatic nodule.
- doesn’t have a capsule
- discrete concentrations of lymphocytes in a reticular mesh framework
- active has a lighter germinal center (inactive dark throughout)
What is the difference between the terms lymphatic nodule and lymph node?
nodule is patches of tissues that is not capsulated vs. nodes as “mini” organs that have a capsule and actually contain nodules
What would you expect to see in a histology specimen of a lymph node?
- dense irregular CT capsule
- trabeculae extending into parenchyma
- reticular tissue
What is the function of the spleen?
- production of immunological response against bloodborne pathogens
- removal of particulate matter & aged/defective blood cells from circulation
Describe histology of the spleen.
- enclosed w/ capsule and has trabeculae
- 2 types of parenchyma (red pulp/white pulp)
Differentiate between red and white pulp.
White pulp - dark because of lymphocyte nuclei - has nodules and immune functions
Red pulp - light reticular fibers and sinuses - filtration functions
What is indicated by the presence of a secondary lymph nodule in the spleen?
that a pathogen has been detected since it is the first lymphatic organ to respond to a pathogen and also that the lymph nodule has been activated
