Erythrocyte Physiology

Question 1

RBC Norms

Answer 1

Men: 40-50%
Women: 35-45%

Question 2

How does the body determine how many RBCs we need?

Answer 2

We use the amount of oxygen getting to the kidneys to measure.

Question 3

HIF-a

Answer 3

Hypoxia inducible factor
Made continually.
If sufficient O2 is getting ot the kidney, it is ubiquinated and destroyed.
If O2 levels are low, HIF-a accumulates and acts as a TF that binds to HIF-b in nucleus to increase transcription of variety of genes.

Question 4

Erythropoetin

Answer 4

Hormone.
Receptor is connected to JAK2/STAT5 pathway.
Acts on stem cell.
Increases maturation rate of committed RBC precursors.

Question 5

Fate of absorbed iron

Answer 5

70% to bone marrow

20% to liver, due to toxicity in high levels.

Question 6

Oxygen capacity of Hb:

Answer 6

1. 34 mL O2/g Hb

20. 1 mL O2/dL of blood

Question 7

Polycythemia

Answer 7

Too many RBCs, leading to more O2 carrying capacity. However, blood becomes thicker and makes the heart work harder to pump.

Question 8

Secondary polycythemia

Answer 8

Bone marrow is normal.

Responding to low oxygen, due to altitude or heart/lung disease.

Question 9

Physiological Polycythemia

Answer 9

Environment has low O2 (altitude), so increase RBC production.

Question 10

Primary Polycythemia (Polycythemia Vera)

Answer 10

Bone marrow is making RBCs when it does not need to.

Question 11

Met-hemoglobinemia

Answer 11

Large amounts of Fe3+.

Hb cannot release O2 –> tissues don’t get needed O2.