Red cells

Question 1

What are the requirements for oxygen carriage and gaseous exchange in tissues?

Answer 1

• Ability to pass repeatedly through microcirculation (deformibility)
• Maintenance of Hb in ferrous state
• Maintain osmotic equilibrium of cells

Question 2

Describe the structure of a RBC

Answer 2

deformable anucleate biconcave disc devoid of intracellular organelles, with 90% of its weight made up by Hb.

Question 3

How long is the life of a RBC?

Answer 3

120d

Question 4

What is a RBC broken down into in the spleen?

Answer 4

Haem–>bilirubin

globin–>amino acids

Question 5

Describe the membrane of a RBC

Answer 5

Has:

• lipid bilayer
• membrane proteins
• membrane skeleton

Question 6

Why does an RBC need energy?

Answer 6

• to keep shape
• to prevent oxidative damage
• to maintain Hb in functional form
• to provide 2,3BPG

Question 7

How is RBC metabolism made possible?

Answer 7

• ATP gene
• gen of NADPH and reduced GSH in hexose monophosphate shunt
• metHb reduction NADH system
• Rapoport-luebering shunt

Question 8

Describe the structure of Hb

Answer 8

2 pairs of globin chains, each attached to a haem molecule, each haem molecule consists of a protoporphyrin ring and an iron molecule which can bind an oxygen molecule.

Question 9

What is the main Hb in adults?

Answer 9

HbA (2 beta chains and 2 alpha)

Question 10

What is the main foetal Hb?

Answer 10

HbF (2 alpha chains and 2 gamma chains)

Question 11

Name another Hb in adults

Answer 11

HbA2 (2 alpha chanins and 2 delta chains)

Question 12

What does a left shifted oxygen saturation curve mean?

Answer 12

increased affinity for oxygen carriage

Question 13

What does a right shifted oxygen saturation curve mean?

Answer 13

decreased affinity for oxygen carriage

Question 14

What does 2,3BPG do to Hb

Answer 14

• decreases its affinity to carry oxygen by binding at the centre of Hb by pulling the beta chains apart.