LYMPH NODES 1 Flashcards
What are the primary (1°) immune system organs?
Bone marrow (where immune cells are produced and B cells mature) and the thymus (where T cells mature).
What are the secondary (2°) immune system organs?
The spleen, lymph nodes, tonsils, and Peyer’s patches.
What is the function of secondary immune system organs?
They allow immune cells to interact with antigens.
What is a lymph node?
A secondary lymphoid organ with multiple afferent vessels and one or more efferent vessels, encapsulated with trabeculae.
What are the main functions of lymph nodes?
Nonspecific filtration by macrophages, circulation of B and T cells, and activation of the immune response.
What is the follicle and what occurs there?
It is located in the outer cortex and is the site of B-cell localization and proliferation.
What is the difference between primary (1°) and secondary (2°) follicles?
Primary follicles are dense and inactive, while secondary follicles have pale germinal centers and are active.
What is the medulla of the lymph node composed of?
Medullary cords (closely packed lymphocytes and plasma cells) and medullary sinuses (which contain reticular cells and macrophages).
What is the function of medullary sinuses?
They communicate with efferent lymphatics to help filter lymph.
What does the paracortex contain?
It contains T cells and is located between the follicles and medulla.Contains high endothelial
venules through which T and B cells enter from blood.
What special structures allow T and B cells to enter from the blood into the paracortex?
High endothelial venules.
What happens to the paracortex in DiGeorge syndrome?
It is underdeveloped.
When does the paracortex enlarge?
During extreme cellular immune responses, such as Epstein-Barr virus (EBV) infection, leading to paracortical hyperplasia and lymphadenopathy.
What does the medulla consist of?
The medulla consists of medullary cords (closely packed lymphocytes and plasma cells) and medullary sinuses (which contain reticular cells and macrophages).
