haematopoiesis Flashcards
where is bone marrow found in adults
flat bones
pelvis
vertebratae
sternum
what is extramedullar haemoatopoiesis
outside of the bone marrow blood production
primary sites of blood cell production and development
bone marroe and thyrmus
secondary sites of blood cell maturations
tonsils lymph nodes lymphatics spleen peyers patch MALT
what is bone marow
spongy tissue inside bones that makes blood cells and stromal cells
red marrow: blood cells
yelow marrow: white blood cells
thymus role
site of T cell development and maturation
immature T cells
called thymocytes and mature in the thymus
role of thymus cortext
positive selection on thyrmocytes
only thymocytes with a functional T cell recetptor are able to progress
role of corext medulla boarder of thymus
negative selection of thrymocytes
apoptosis of those recognsing self
role of medulla of thymus
differentiation of T cells
into either:
- T helper
- cytotoxic
what happens to the thymus as we age
decreases in sie
contributes to a decline in immune functon as we age
route of lymph
travels in lymph vessels and through nodes
collects in the thoracic ducts and drains back into the subclavian vein
role of the lymph
screens for the immune system
foreign antigens can find their way into the lymph and become trapped in nodes
lymph nodes
site of activtion and division of antigen activated T and B cells
germinal centres in lymph nodes
germinal centres are clusters of B cells and T helper cells ( to help the B cells)
B cells can multiply and become plasma cells ones being sensities to fight the infection
structure of a lymph node
3 zones: - cortext primary follicles of B cells which can enlarge to form germinal centres - paracortext contains T cells - medulla contains macrophage
the spleeeenen
filter of blood, removes old or damaged blood cells
strucure of the spleen
blood enteres via splenic artery
passes through white pulp and then red pulp
role of splenic white pulp
forms a PALS, periaretiolar lymphoid sheath containing T cells
germinal centres here to for B cells to mature
role of splenic red pulp
mesh of splenic sunuses and cords
contains macrophage and Ab secreting plasma clls
RBC are filteres through sinuses
macrophage phagocytose old cells
MALT
mucosal assoicated lymphoid tissue
role of MALT
organised lyphoid tissue to protect mucus membranes which are a major pathogen entry ste
MALT includes
tonsils
peyer patches
appendix
lymphoid follicles in intestine and airways and genital tract
tonsils location
palatine
lingual
pharyngeal
