lymphoid organ histology Flashcards
where do B cells maturation occure
Bone Marrow
Bursa of Fabricus in Birds
Peyers Patches in Ruminants
where are T cells matured
Thymus in Mammals
what cells differentiate into plasma cells (and therefore then antibodies)
B cells
what is the function of primary lymphoid tissue
generate specific immune cells
what is the function of secondary lymphoid tissue
generate immune responses (recognise foreign antigens)
which lymph organs have a cortex and a medulla
thymus
Bursa of Fabricius
Lymph nodes
what happens to the thymus with sexual maturity
it involutes and is replaced with fat
why is it important that pathogens don’t enter the thymus
WBC will be exposed to them and not recognise them as a foreign antigen
how can you identify a histology of the thymus
bright pink Hassals Corpuscles in the medulla
what is found between the cortex and medulla of the bursa of fabricius
pseudostrratisfied of columnar epithelium and undifferentiated epithelial (capillary cells)
how may the bursa of Fabricius also act as a secondary lymphoid organ
have columnar epithelium also which allow it to take in and present antigens
in which animals are Peyers patches considered a primary lymphoid organ
ruminants
What is found at the edge of the lymph node
subcapsula sinus
(beneath the Connective tissue capsule)
what is a germinal centre
region in the cortex where B cells mature
in which animals are lymph nodes considered inside out and how is it different
pig
afferent lymphoid at the base
germinal centres in the centre
what is found in the spleen capsule and what is its purpose
smooth muscle
for contraction so erythrocytes are released
what is the function of red pulp in the spleen
contain blood vessels - secrete more erythrocytes when needed
breakdown erythrocytes, retrieve iron
filter blood to remove pathogens or dead erythrocytes
what is the function of the white pulp
contains lymphoid tissue
which cells retrieve iron in the red pulp
haemosiderophages
where are T cells found in the spleen
Periarteriolar lymphoid sheath (in the white pulp)
what cell type lines the tonsils
stratified squamous epithelium
what is the function of the intraepithelial lymphocytes
recognise foreign antibodies
what lies on the outside of the tonsils
thin connective tissue
what are trabeculae
thin fibres of smooth muscle
