Chapter 40 - Transport of Oxygen and Carbon Dioxide in Blood and Tissue Fluids

Question 1

What is the initial pressure difference that causes oxygen to diffuse into the pulmonary capillary?

Answer 1

104 – 40 = 64 mm Hg.

Question 2

How much oxygen does a person’s body require during strenuous exercise?

Answer 2

20x the normal amount of oxygen.

Question 3

Why isn’t the PO2 of blood being pumped by the left heart into the aorta not equal to the alveolar P02?

Answer 3

Because 2% of blood that was shunted mixes with the oxygenated blood to bring it down to about 95 mm Hg.

Question 4

What is the PO2 leaving the tissue capillaries and entering the systemic veins?

Answer 4

40 mm Hg.

Question 5

What is the effect on the interstitial fluid PO2 when blood flow thru it increases?

Answer 5

Greater quantities of oxygen are transported into the tissue, raising the tissue PO2.

Question 6

What determines tissue PO2?

Answer 6

A balance between 1) Rate of oxygen transport to the tissues in the blood and (2) the rate at which the oxygen is used.

Question 7

What is the normal intracellular PO2?

Answer 7

Ranges from 5 to 40 mm Hg, averaging about 23 mm Hg.

Question 8

What is the major difference between diffusion of CO2 and of O2?

Answer 8

CO2 can diffuse 20x faster.

Question 9

What is the intracellular PCO2?

Answer 9

46 mm Hg

Question 10

What is the interstitial PCO2?

Answer 10

45 mm Hg.

Question 11

What is the PCO2 of the arterial blood entering the tissues?

Answer 11

40 mm Hg.

Question 12

What is the PCO2 of the venous blood leaving the tissues?

Answer 12

45 mm Hg.

Question 13

What is the PCO2 of the blood entering the pulmonary capillaries at the arterial end?

Answer 13

40 mm Hg.

Question 14

What is the hemoglobin saturation at PO2 of 100 mm Hg?

Answer 14

100%,O2 bound in all four heme groups.

Question 15

What is the hemoglobin saturation at PO2 of 40 mm Hg?

Answer 15

75%, O2 bound in ¾ of heme groups.

Question 16

What is the hemoglobin saturation at PO2 of 25 mm Hg?

Answer 16

50% (P50), O2 bound in 2/4 of heme groups.

Question 17

How much grams of hemoglobin does a normal person contain in 100 milliliters of blood?

Answer 17

About 15 grams of hemoglobin.

Question 18

How much Oxygen can a gram of hemoglobin contain?

Answer 18

About 1.34 milliliters of Oxygen.

Question 19

How much oxygen is in 100 milliliters of blood?

Answer 19

20 milliliters of Oxygen.

Question 20

Under normal conditions, how much milliliters of Oxygen are transported from the lings to the tissues by each 100 milliliters of blood flow?

Answer 20

5 milliliters of oxygen.

Question 21

What is the utilization coefficient?

Answer 21

The percentage of the blood that gives up its oxygen as it passes thru the tissue capillaries.

Question 22

What are things that can make the hemoglobin-O2 dissociation curve shift to the right?

Answer 22

Occurs when the affinity of hemoglobin for O2 decreases: CADET face right
C= CO2 (High)
A= Acid/Altitude (Low/High)
D= DPG (2,3-DPG)
E= Exercise
T= Temperature (High)

Question 23

What is the Bohr Effect?

Answer 23

States that hemoglobin’s oxygen binding affinity is inversely related both to acidity and to the concentration of carbon dioxide.

Question 24

Under normal conditions, the rate of oxygen usage by the cell is controlled by ultimately what?

Answer 24

The rate of energy expenditure within the cells – that is, by the rate at which ADP is formed from ATP. It is not the level of oxygen pressure.

Question 25

How much stronger can carbon monoxide combine with hemoglobin compared to oxygen?

Answer 25

250x stronger.

Question 26

At what partial pressure of carbon monoxide can be fatal?

Answer 26

Only 0.6 mm Hg.

Question 27

How can a patient poisoned severely with carbon monoxide be treated?

Answer 27

Pure Oxygen or 95% Oxygen with 5% CO2 to strongly stimulate the respiratory center and cause taquipnea.

Question 28

How much carbon dioxide is transported from the tissues to the lungs in each 100 milliliters of blood?

Answer 28

4 milliliters.

Question 29

What is the Haldane Effect?

Answer 29

Binding of oxygen with hemoglobin tends to displace carbon dioxide from the blood.

Question 30

What causes the Haldane Effect?

Answer 30

1. The more highly acidic hemoglobin (binding of oxygen makes it more acidic) has less tendency to combine with carbon dioxide to form carbaminohemoglobin.
2. The increase acidity of the hemoglobin also causes it to release an excess of ions, and these bind with bicarbonate ions to form carbonic acid.

Question 31

What is the respiratory exchange ratio (R)?

Answer 31

Rate of carbon dioxide output/ rate of oxygen uptake.