Intro to haem Flashcards
what are blood cells derived from
pluripotent stem cells
where is blood made in an embryo
yolk sac (till week 10)
then liver then marrow
week 12+ in spleen
at birth, where is blood made
mostly bone marrow
liver and spleen when needed
from birth to maturity, where is blood made
bone marrow
no. of active sites decreases (but still retains ability to)
in an adult, where is blood made
axial skeleton bone marrow
2 types of stem cells
long term
short term
feature of a stem cell
able to regenerate
what type of stem cell is more likely to regenerate
long term
short term more likely to differentiate
what do short term stem cells differentiate into
multipotent progenitors
two groups after multipotent progenitors
myeloid
lymphoid
two groups myeloid is divided into
megakaryocyte-erythroid progenitor (MEP)
granulocyte-monocyte progenitor (GMP)
what does MEP divide into
erythrocytes and platelets
what does GMP divide into
granulocytes (neutrophils, eosinophils etc)
macrophages
what does common lymphocyte precursor divide into
dendritic cells
T cells
NK cells
B cells
at what stage of development does an erythrocyte shed its nucleus
othochromatic normoblast
at what stage does an erythrocyte shed its RNA
reticulocyte
what are platelets made on
megakaryocyte - platelets ‘bud’ off
segmented nucleus
neutrophil (polymorph)
bi-lobed nucleus
bright orange/red granules
eosinophil
large deep purple granules obscuring nucleus
basophil
large single nucleus
vacuolated
monocyte
how long do monocytes circulate before entering tissues to become macrophage
1 week
small with condensed nucleus
rim of cytoplasm
mature lymphocytes
large cell, plentiful blue cytoplasm
around red cells
active lymphocyte
how to recognise blood precursors
immunophenotyping
bioassays
what is immunophenotyping
recognises expression of proteins on surface of cells
what are bio-assays
culture in vitro to show lineage
common site of bone marrow aspiration
posterior iliac crests
life span of RBC
120 days
what removes RBC from circulation
spleen and liver
life span of neutrophils
7-8 hours
life span of platelets
7-10 days
when RBCs engulfed, what are Hb and haem group broken down to
Hb - amino acids
haem group (minus iron) - bilirubin
iron - binds to transferrin in blood and is recycled
what happens to bilirubin from haem group
transported to liver and secreted into bile
how does body know to make more RBC
kidney senses reduced oxygen carrying capacity and releases EPO
what haematological problem might renal disease be associated with
anaemia
effect of EPO
stimulates RBC production in bone marrow
