Lecture 5: Gas Transport and Erythrocyte Physiology

Question 1

What is the function of erythrocyte?

Answer 1

1. Carries oxygen to body
2. Carries carbon dioxide to lungs
3. Acid/base buffering

Question 2

What matures into erythrocytes entering circulation?

Answer 2

Stem Cells –> Reticulocytes

Question 3

What promotes production of red blood cells?

Answer 3

Erythropoietin (EPO)

Question 4

Where is EPO produced?

Answer 4

Kidney

Question 5

What promotes production of EPO?

Answer 5

Anemia
low Hb
Decreased RBF
Central Hypoxia 
Low blood flow/volume

Question 6

What regulates erythropoiesis?

Answer 6

Hypoxia Inducible Factor (HIF)

Question 7

Where do red blood cells “die?”

Answer 7

Spleen via macrophages

Question 8

What happens to heme?

Answer 8

Option 1: Heme –> Ferritin –> bone

Option 2: Heme –> Bilirubin –> Feces

Question 9

What are the two ways oxygen is transported in blood?

Answer 9

1. Dissolved (inadequate)

2. Bound to hemoglobin

Question 10

How many oxygen molecules are bound to 1 hemoglobin

Answer 10

4 oxygen molecules

Question 11

What are the 4 heme sites found on a hemoglobin?

Answer 11

2 alpha

2 beta

Question 12

What does a “left shift” in an oxygen dissociation curve mean?

Answer 12

Increased affinity of hemoglobin for oxygen

-increased oxygen saturation

Question 13

What diseases have a “left shift” in an oxygen dissociation curve?

Answer 13

Polycythemia: extra RBC and increased blood volume
Methemoglobinemia: increased met-hemoglobin

Question 14

What does a “right shift” in an oxygen dissociation curve mean?

Answer 14

Decreased affinity of hemoglobin for oxygen

-unloading oxygen

Question 15

What diseases have a “right shift” in an oxygen dissociation curve?

Answer 15

Anemia

-can also think of exercise

Question 16

With a “right shift” in an oxygen dissociation curve, there is also an increase in?

Answer 16

Increased Hydrogen (decreased pH)
Increased temp
Increased CO2 content
Increased 2,3-DPG

Question 17

Folate or B12 deficiency results in what?

Answer 17

Megaloblastic macrocytic anemia

Question 18

Poor B12 absorption leads to what?

Answer 18

Pernicious anemia

Question 19

What is microcytic anemia?

Answer 19

small RBC due to iron deficiency

Question 20

What is hypochromic anemia?

Answer 20

pale RBC due to deficienct transport of transferrin

Question 21

What is hemochromatosis?

Answer 21

Iron build up/overload

• liver cirrhosis
• skin pigmentation
• diabetes

Question 22

What is the respiratory quotient?

Answer 22

RQ = [Vol of CO2 produced]/[Vol of O2 consumed]

Question 23

What is the RQ of carbs?

Answer 23

1

Question 24

What is the RQ of fats?

Answer 24

0.7

Question 25

What is the RQ of protein?

Answer 25

0.9

Question 26

How is carbon dioxide transported in blood?

Answer 26

1. Dissolved carbon dioxide (inadequate)
2. Carbamino compounds
3. As bicarbonate

Question 27

What are carbamino compounds?

Answer 27

Compound composed by the addition of carbon dioxide with a free amino group

Question 28

How is bicarbonate formed?

Answer 28

1. CO2 and Water —> H2CO3 via carbonic anhydrase

2. H2CO3 –> HCO3- + H+

Question 29

What happens to hydrogen from H2CO3?

Answer 29

Buffered into red blood cells and carried in venous blood

Question 30

What happens to HCO3 from H2CO3?

Answer 30

Exchanged for chloride across RBC and carried to lungs