Lec 9

Question 1

Describe the transport of oxygen in the blood

Answer 1

It binds to hemoglobin and very slightly dissolves in plasma

Question 2

How many polypeptide chains are there in a hemoglobin? What does it mean to be fully saturated?

Answer 2

there are 4, and fully saturated has 4 oxygens bound

Question 3

What does the binding of O2 rate depend on?

Answer 3

1. PO2
2. temperature
3. pH of blood
4. P CO2
5. BPG in blood (glucose product)

Question 4

What is the O2-hemoglobin curve shape? What are the key values?

Answer 4

It is sigmoidal and has a slope from 10-50mm Hg and plateaus at 70-100mm Hg

Question 5

What is the Hb saturation in blood leaving the lungs?

Answer 5

98%

Question 6

What is the Hb saturation when the PO2 is less than 40 mmHg

Answer 6

Still 75%

Question 7

What is venous reserve?

Answer 7

Only 25% of O2 is unloaded during the first pass, which means in exercise conditions there is still more O2 to be given

Question 8

What happens to PO2 at high altitude? What effect does this have on saturation of Hb?

Answer 8

The PO2 goes up significantly, which makes for very small changes in hemoglobin saturation for changes in PO2

Question 9

What produces BPGs? What do they do?

Answer 9

RBCs produce BPGs, which bind to Hb to reduce affinity for O2

Question 10

What decreases hemoglobin affinity for O2?

Answer 10

increase in temp, PCo2, pH, BPG

Question 11

What does low hemoglobin O2 affinity do to the blood?

Answer 11

It means the hemoglobin unloads more O2

Question 12

Why does it make sense that CO2 decreases hB O2 affinity?

Answer 12

The Bohr effect states that H+ decreases affinity, which is a byproduct of the CO2 H2O rxn in blood

Question 13

What are the 3 ways that CO2 is transported in the blood?

Answer 13

1. Dissolved in plasma
2. Bound to Hb (carbaminohemoglobin)
3. bicarbonate ion in plasma

Question 14

What is the Haldane effect?

Answer 14

HHb in tissues binds more CO2 than O2, which leads to blood taking more CO2 from tissues away

Question 15

Where does the H2CO3 -> HCO3- + H+ happen?

Answer 15

In red blood cells containing carbonic anhydrase

Question 16

Where does most CO2 get transported in the blood?

Answer 16

The bicarbonate ion in plasma

Question 17

What is the chloride shift in RBCs?

Answer 17

Chloride goes into the cell to balance the diffusion of sodium bicarbonate to plasma

Question 18

How is carbon dioxide moved from the blood to the alveola?

Answer 18

1. CO2 dissolved in plasma moves out
2. CO2 bound to Hb is released and moves out
3. CO2 bicarbonate ion goes back into the RBC where it becomes CO2 and water again and moves out

Question 19

What happens if blood is too acidic?

Answer 19

It is buffered by Hb or proteins

Question 20

What happens if blood is too basic?

Answer 20

The bicarbonate ion diffuses into plasma

Question 21

What does shallow rapid breathing do to blood pH?

Answer 21

Accumulation of CO2 in the blood leads to a basic pH

Question 22

What does deep breathing do to blood pH?

Answer 22

Flushes out CO2, which leads to an acidic pH

Question 23

What are the two brain areas responsible for respiration?

Answer 23

The ventral respiratory group and the dorsal respiratory group

Question 24

What nerves innervate the dorsal respiratory group?

Answer 24

The phrenic and intercostal nerves

Question 25

What is the VRG responsible for?

Answer 25

It is the pacesetting respiratory center and inspiratory center

Question 26

What happens when VRG neurons fire?

Answer 26

Passive expiration