Red Blood Cells

Question 1

CO2 Transport

Answer 1

10% dissolved
22% as carbamino
68% as HCO3-

Question 2

O2 affinity

Answer 2

Rightward shift = decrease in affinity for O2
CO2/H+/Cl- = rightward shift
increase in presence of 2,3-DPG = rightward shift

Question 3

Foetal Hb (HbF)

Answer 3

2 alpha & 2 gamma subunits
Binds more strongly to O2 than HbA
Low affinity for 2,3-DPG

Question 4

Bohr Effect

Answer 4

Increase in blood CO2/ decrease in blood pH = decreased affinity for O2
CO2 and H+ bind to Hb at a different site

Question 5

Erythrocyte Disorders

Answer 5

Methemoglobinemia = Hb cannot transport O2 - Fe is oxidised (Fe3+)
CO poisoning = CO displaces O2, blood turns bright red, treat with 95% O2
Polycythemias = increased number of RBCs, clogs BVs, can be pathological or physiological (living at high attitude)

Question 6

Vitamin B12 and Folic Acid

Answer 6

important for rapidly dividing tissues
used in production of nucleotides
deficiency caused by diet, malabsorption and increased utilisation
megaloblastic anaemia

Question 7

Reticulocytes

Answer 7

RBC precursor
last 2 days in the blood, then become a definitive RBC
used as a diagnostic tool in anaemia

Question 8

Breathing controlled by O2, CO2 and H+

Answer 8

Main driver of increasing respiratory rate: H+ in CSF
CO2 enters CSF to make H+ and HCO3-
Medullary receptors sample from interstitial and CSF fluid

Question 9

Erythropoiesis

Answer 9

During embryogenesis: liver, spleen, lymph nodes, yolk sac
After birth: bone marrow
After age 20: membranous bones
Driven by erythropoietin - made in kidney

Question 10

Iron requirement for RBC production

Answer 10

Fe stored intracellularly as Ferritin and Haemosiderin

Fe stored in reticulo-endothelial system

Question 11

Red Blood Cells

Answer 11

anucleate, 7umx2um, 120 day survival
5million per um blood
Packed cell volume: 40-52% in men, 36-48% in women
Hb: 13-17 g/dL in men, 12-16 g/dL in women
Mean cell haemoglobin: 27-34 pg
Mean corpuscular volume: 80-100 fL