Haem- physiology and pathophysiology Flashcards
what is blood
a specialised fluid (tissue) composed of cells suspended in a liquid (plasma)
three types of blood cells
red blood cells
white blood cells
platelets
Haematopoiesis
production of blood cells
site of Haematopoiesis in an embryo
yolk sac (stops by week 10)
then liver (starts by week 6)
then marrow (starts by week 16)
3rd-7th month in the spleen
site of Haematopoiesis at birth
mostly bone marrow, liver and spleen when needed
site of Haematopoiesis from birth to maturity
number of active sites in bone marrow decreases but retain ability for haematopoiesis
site of Haematopoiesis in adults
haematopoiesis restricted to skull, ribs, sternum, pelvis, proximal ends of femur (axial skeleton)
different types of white blood cells
granulocytes
monocytes
lymphocytes
examples of granulocytes
eosinophils
basophils
neutrophils
neutrophils granules
neutral staining granules
function of neutrophils
immediate defence cell- phagocytosis
most abundant white blood cell
neutrophils
neutrophils nucleus
segmented nucleus
eosinophils nucleus
bilobed nucleus
eosinophils granules
bright orange/red granules
function of eosinophils
fight parasitic infections
involved in hypersensitivity- allergies
basophils granules
large deep purple granules obscuring nucleus
contain histamine
largest type of white blood cell
monocyte
monocytes become-
macrophages
which cell is longer lived- monocytes/neutrophils
monocytes
Immunophenotyping
expression profile of proteins (antigens) on the surface of cells
Bioassays
culture in vitro and show lineage of progeny in different growth conditions
common sites for bone marrow aspiration and biopsy
posterior iliac crests/sternum
tibia in children
RBCs structure
biconcave disc
flexible
PROS AND CONS of RBCs being full of haemoglobin
pros- carries oxygen
cons- high oncotic pressure, oxygen rich environment (oxidation risk)
PROS AND CONS of RBCs having no nucleus
pros- more deformable, and more room for Hb molecules
cons- can’t divide, can’t replace damaged proteins - limited lifespan
PROS AND CONS of RBCs high surface area/volume ratio
pros- gas exchange
cons- need to keep water out
PROS AND CONS of RBCs flexibility
pros- to squeeze through capillaries
cons- specialied membrane requirements that can go wrong
structure of haemoglobin
tetrameric globular protein
one haem group attached to each globular chain
which is the major form of haemoglobin present in adults
HbA
HbA structure
2 alpha chains
2 beta chains