Blood physiology Flashcards
(11 cards)
blood compoments
haemocrit (45%) :
RBC and platelets
WBC
- lymphocytes
- granulocytes (neutrophil, eosinophil, basophil)
- monocytes
plasma (55%) - includes plasma proteins
plasma protein functions
colloidal osmotic pressure
pH buffering
transport (binding proteins)
immunity
blood coagulation
sites of haematopoiesis
yolk sac (embryo)
liver spleen lymph node (foetus)
bone marrow afterwards:
all bones (5 years old)
axial skeleton (adult)
platelets description and function
small fragments of megakaryocytes, no nucleus, small lifespan
aggregate together to form a clot, aids coagulation enzymes to form fibrin strands that hold clot
eosinophil and basophil function
destroys parasites extracellularly, weak phagocytosis of allergens
activates other WBCs during inflammation and allergic reactions, release histamine
lymphocytes types and functions
B: become plasma cells that produce and release antibodies (humoral immunity)
T: killer T cell etc (cell mediated immunity)
Hb structure and function
4 globin subunits (2 alpha 2 beta)
1 Haem unit (1 Fe and 1 protoporhyrin)
binds loosely and reversibly to Fe
RBC destruction
removed by spleen, liver, bone marrow due to reduced flexibility/rupture
phagocytosed by macrophages, recycle Fe, rest of Hb disposed as bilirubin
erythropoiesis
decrease cell size, lose nucleus and organelles, incease haemoglobin content
HSC (hemocytoblast to committed proerythroblast) to early and late erythroblast to normoblast to reticulocyte to erythrocyte
erythropoiesis homeostasis
S: hypoxia
R/M: kidney and liver release erythropoietin (EPO)
E: erythropoietin stimulates bone marrow to speed up maturation of HSCs and erythropoiesis
F: negative feedback etc
RBC count HB conc Haemocrit
M: 5x10^12, 150g/L, 0.45
F: 4.8x10^12, 135g/L, 0.42
