GPT Spleen & Lymph Nodes Flashcards
(17 cards)
What is the function of lymph nodes?
Filter lymph, present antigens to lymphocytes, support clonal expansion
What surrounds and supports the lymph node?
A connective tissue capsule with inward trabeculae
What is found in the outer cortex of a lymph node?
Lymphoid follicles primarily composed of B cells
What is the difference between a primary and secondary follicle?
Primary: inactive B cells; Secondary: contains germinal center with active B cells
What is the paracortex of a lymph node rich in?
T cells and high endothelial venules (HEVs) for lymphocyte entry
What is the medulla of a lymph node composed of?
Medullary cords (B cells, plasma cells) and medullary sinuses (macrophages)
What enters lymph nodes via high endothelial venules (HEVs)?
Naïve lymphocytes from the bloodstream
What cells filter lymph in the lymph node sinuses?
Macrophages
What is the main function of the spleen?
Filter blood, remove old RBCs, mount immune response to blood-borne antigens
What are the two major structural regions of the spleen?
White pulp and red pulp
What is found in the white pulp of the spleen?
PALS (T cells) and follicles (B cells)
What does PALS stand for, and what does it contain?
Periarteriolar lymphoid sheath; contains T cells around central arteries
What is found in the red pulp of the spleen?
Splenic cords (macrophages, RBCs) and sinusoids (fenestrated capillaries)
What is the function of the splenic sinusoids?
Filter and remove old or damaged RBCs
What is the function of splenic macrophages?
Phagocytose old RBCs, pathogens, and recycle iron
What organisms pose risk in asplenic patients?
Encapsulated bacteria: Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis
What is a key difference between lymph nodes and spleen in terms of what they filter?
Lymph nodes filter lymph; spleen filters blood
