Haemopoiesis Flashcards
(29 cards)
what is haemopoiesis
formation of blood cells
types of white cells
granulocytes
macrophages
lymphocytes
types of granulocytes and their functions
neutrophils: phagocytosis
eosinophils: destroy parasites, modulate hypersensitivity reactions
basophils: modulate hypersensitivity reactions
precursor for macrophage
monocytes
types of lymphocytes
B cells: antibodies
T cells: cell mediated immunity
Natural killer cells: anti-viral/tumour
life span of:
RBCs
Neutrophils
Platelets
RBCs = 120 days Neutrophils = 7-8 hours Platelets = 7-10 days
precursor for platelets
megakaryocytes
progression from premature cell to mature neutrophil
pre-myeloblast – myeloblast – premyelocyte – myelocyte – metamyelocyte – neutrophil
what is meant by the term ‘blast’
primitive nucleated precursor cell
what are haemopoietic stem cells derived from
mesoderm
where is the first site of erythroid activity in an embryo
yolk sac (stops by week 10)
where are the other sites of erythroid activity in an embryo and their time frames
liver (starts by week 6)
spleen (starts by week 12)
bone marrow (starts by week 16)
main sites of haemopoiesis in an adult
bone marrow of skull, ribs, sternum, vertebra,pelvis
what are the names of the cells that:
form bone
break down bone
bone forming = osteoblasts
bone break down = osteoclasts
where is a bone marrow biopsy often taken
posterior iliac crest
how does blood enter the bone
arteries feed into sinusoids
what are sinusoids
flattened capillaries with gaps between epithelial cells- regulate which cells pass in and out of blood vessels
importance of sinusoids
allow formed blood cells to pass through gaps in endothelial cells to enter circulation
link between RBCs and sinusoids
release of red cells is associated with sinusoidal dilatation and increased blood flow
link between megakaryocytes and sinusoids
extend long branching processes called pro platelets into the sinusoidal blood vessels - blood sheers off platelets and they enter the blood stream
what is red marrow and what is yellow marrow
red = haemopoietically active yellow = fatty inactive
how does the composition of marrow change with age
increase in yellow marrow
what is the myeloid: erythroid ratio
relationship of neutrophils and precursors to proportion of nucleated red cell precursors
what is neutrophil maturation regulated by
G-CSF (granulocyte-colony stimulating factor)
