Erythropoiesis

Question 1

Lifespan of an RBC

Answer 1

Around 120 days

Question 2

Site of production of an RBC

Answer 2

Red bone marrow

Question 3

What happens to haem when the spleen breaks down RBCs?

Answer 3

Converted to bilirubin and excreted in faeces/urine

Question 4

Hormone which regulates RBC production

Answer 4

Erythropoietin (EPO)

Question 5

Where is EPO secreted from and in response to what?

Answer 5

Cortical interstitial cells of kidney; hypoxaemia

Question 6

What is haematocrit?

Answer 6

Proportion of whole blood taken up by RBCs

Question 7

Why can RBCs only use glycolysis?

Answer 7

Lack mitochondria

Question 8

What is the role of 2,3 BPG?

Answer 8

Promotes release of oxygen from haemoglobin at low oxygen concentration (e.g. in respiring tissue)

Question 9

What is the role of glutathione?

Answer 9

protects against the toxic effects of reactive oxygen species

Question 10

In which condition is there a lack of reduced glutathione?

Answer 10

Glucose-6-phosphate dehydrogenase deficiency

Question 11

Means of CO2 transport in blood (3)

Answer 11

Dissolved in solution (10%)
Bound to Hb (30%)
As bicarbonate ion (60%)

Question 12

Which enzyme facilitates the transport of CO2 as HCO3-?

Answer 12

carbonic anhydrase

Question 13

Structure of adult haemoglobin

Answer 13

4 protien sub-units, each with a single haem group which can bind one oxygen molecule

Question 14

When fully saturated, 1g Hb will bind how much oxygen?

Answer 14

1.34ml

Question 15

Structure of adult haemoglobin

Answer 15

alpha-2, beta-2

Question 16

Structure of foetal haemoglobin

Answer 16

alpha-2, gamma-2

Question 17

Structure of haem group

Answer 17

Porphyrin ring with Fe at centre

Question 18

Describe oxygen binding to haemoglobin

Answer 18

Shows co-operativity, which enables rapid off-loading of oxygen at the tissues

Question 19

How does foetal haemoglobin differ from adult? (2)

Answer 19

1. Higher affinity for oxygen

2. Lower affinity for 2,3-BPG