Embryology and Histology of Lymphoid Tissue- Reynolds Flashcards
What are the three types of lymphocytes?
null- has no surface markers
T- cell mediated and recruits different cell types
B- recognizes noncells and turns into plasma cells; has to do with the humoral response
What are primary lymphoid structures?
bone marrow and thymus
What are secondary lymphoid structures?
any where mature lymphocytes might encounter pathogens
When does embryonic lymphatic structures begin to develop?
During the 5th week, after the cardiovascular system is constructed
Name the 6 lymph sacs
2 jugular
2 illiac
1 retroperioteneal
1 cistern chyli
What is the difference between vasculogenesis and angiogenesis?
Vasculogenesis is the formation of blood vessels where there was none
Angiogenesis is budding or sprouting from previous vessels
What is congenital lymphedema?
diffuse swelling of one part of the body
What is cystic hygroma?
swelling on inferiolateral neck with large fluid filled cavities (jugular lymph)
a form of congenital lymphedema
Describe the three main regions of the lymph nodes
Cortex- (outside) has germinal centers with B lymphocytes
Paracortex- contains T lymphocytes
Medulla- (middle) has lymphocytes and macrophages
Contains many afferent vessels and one efferent vessel
Does the nodes have a capsule? If so, what is it made of?
Yes, Dense CT
Does the thymus have a capsule? If so, what is it made of?
Yes, but it is made of loose CT so it is very thin
Describe the regions of the thymus
Has NO germinal centers
Has dark cortex and medulla with CT septum
Cortex contains thymocytes, macrophages, dendritic, and reticular cells
Medulla has naive T cells, macrophages, and reticular cells
Describe the spleen
Large and highly vascularized
No cortex or medulla, but rather white and red pulp
White- central artery
Red- veins and sinusoids
Both of these may look like they have germinal centers
Does the spleen have a capsule?
Yes, it has a thick capsule with trabeculae
What is MALT?
mucosa associated lymph tissue
Has germinal centers
