Erythrocyte Physciology

Question 1

What is the general composition of blood?

Answer 1

Formed elements and plasma

The plasma consist of water, ions and proteins

Question 2

What is the function of blood?

Answer 2

deliver required elements for metabolism like oxygen, remove waste, maintain homeostasis and help in immune responses

Question 3

What elicits erythropoiesis?

Answer 3

A decrease in oxygenation to the kidneys will cause the body to produce more RBCs.

Question 4

What is HIF?

Answer 4

Hypoxia inducible factor- This will react to low O2 levels and promote erythropoiesis

Question 5

How is HIF regulated?

Answer 5

HIF is constantly being synthesized but will be ubiquinated and destroyed in the the presence of sufficient oxygen.

Question 6

How does HIF promote erythropoiesis?

Answer 6

HIF-alpha acts as a transcription factor that will bind with HIF-beta in the nucleus. This will then lead to increased transcription of a Erythropoietin

Question 7

What is erythropoietin?

Answer 7

a glycoprotein that increases the differentiation of stem cells to proerythroblast for RBC synthesis. It will also increase the maturation rate of committed erythrocytic precursors.

Question 8

Why is stomach acid important to iron absorption?

Answer 8

The acidic enviroment favors the ferric state so a majority of the iron will move into the intestine

Question 9

What is the distribution of ingested iron to the body?

Answer 9

20 percent liver, 70 percent RBC, 10 percent other

Question 10

What is the average carrying capacity of the hemoglobin?

Answer 10

1.34 mL O2/g of Hb

Question 11

What is oxygen capacity?

Answer 11

The total amount of oxygen that can be carried in our blood assuming every available heme had an oxygen bound to it

Question 12

Calculate the oxygen capacity of someone with 15gm hb/dL blood.

Answer 12

1.34 mL O2/g of blood x 15 g Hb/dL blood= 20.1 mL O2/dL blood

Question 13

Calculate the oxygen capacity of someone with 13.4gm Hb/dL blood.

Answer 13

1.34 mL O2/g of blood x 13.4g Hb/dL blood = 17.9 mL O2/dL blood

Question 14

What is oxygen content?

Answer 14

The amount of oxygen that is actually being carried in our blood. Not all the heme has to have oxygen bound to it. Measured in percent saturation

Question 15

What is the equation for oxygen content?

Answer 15

Oxygen content= oxygen capacity x percent saturation

Question 16

Calculate the oxygen content of someone with a capacity of 20.1 and a saturation of 96 percent.

Answer 16

20.1 x .96= 19.30 oxygen content

Question 17

Calculate the oxygen content of someone with 14.2 gm Hb/dL blood and a saturation of 97 percent.

Answer 17

1. 34 mL O2/ g of blood x 14.2 g Hb/dL of blood= 19.03

19. 03 x .97= 18.46 oxygen content

Question 18

What does a RBC use ATP for?

Answer 18

flexibility of the membrane, ion-transport, maintaining Fe2+ rather than Fe3+, and prevent the oxidation of Hb.

Question 19

What is polycythemia?

Answer 19

too many RBCs

Question 20

What are the effects of polycythemia?

Answer 20

more oxygen carrying capacity, increased viscosity, heart works harder at pumping blood

Question 21

What is physiological polycythemia?

Answer 21

It falls under secondary polycythemia and is the result of elevated altitude more RBCs are produced

Question 22

What is secondary polycythemia?

Answer 22

too many RBCs resulting from a change in oxygen levels. Can be from altitude (physiological) or from heart/lung disease

Question 23

What is polycythemia Vera?

Answer 23

Primary polycythemia- too many RBCs that is the result of the bone marrow making more than needed. Usually from a mutation in thromnopoietin.

Question 24

What does a left shift in the Hb-O2 curve mean?

Answer 24

An increase in the affinity of Hb for O2

Question 25

What does a right shift in the Hb-O2 curve mean?

Answer 25

A decrease in the affinity of Hb for O2

Question 26

What are some things that cause a right shift in the Hb-O2 curve?

Answer 26

Low pH, high CO2, increased temp and increase in 2,3BPG

Question 27

What is met-hemoglobin?

Answer 27

When the Fe in hemoglobin goes from ferrous to ferric state. This results in oxygen being unable to bind to the site and will increase the affinity for O2 of other chains with ferrous state.