Lecture 2 - Red Cells, Haemoglobin, and Introduction to Anaemia

Question 1

Reason for biconcave shape?

Answer 1

increase surface area and increased flexibility (through capillaries) - determined by membrane and cytoskeletal proteins

Question 2

Abnormality in RBC membrane?

Answer 2

hereditary spherocytosis - shortened lifespan

Question 3

Haemoglobin in reduced state?

Answer 3

maintains osmotic equilibrium, supported by ATP from glycolysis and NADPH from HMP shunt - inherited defects in enzyme pathways (e.g. G6PD) leads to haemolysis

Question 4

Causes of anaemia?

Answer 4

iron deficiency causing decreases haem production, thalassemia impairing globin chain production

Question 5

Changes with differentiation from proerythroblast to RBC?

Answer 5

increase in Hb, cromatin clumping, extrude nucleus, loss of RNA

Question 6

Kinetcis of Erythropoiesis?

Answer 6

takes 10 days, therefore will take at least 10 days for iron supplements to demonstrate improvement

Question 7

Erythropoietin?

Answer 7

glycoprotein, produced in kidney, responds to low oxygen tensions

Question 8

Erythropoietin feedbakc loop?

Answer 8

peritubular interstitial cells of kidney detects low oxygen, releases erythropoietin to increase erythropoiesis

Question 9

Binding of erythropoietin receptor?

Answer 9

stimulation of BFU-E and CFU-E, increased Hb synthesis, reduced RBC maturation time, increased reticulocyte release

Question 10

RBC destruction?

Answer 10

removed in liver or spleen, Hb broken down: globin chains reduced into A.A, haem iron into bone marrow and protoporphyrin into bilirubin (haemolysis -> jaundice)

Question 11

Body response to anaemia?

Answer 11

increased heart rate, stroke volume, right shift in Hb dissociation curve