Chapter 40 - Guyton

Question 1

The transport of oxygen and carbon dioxide is dependent on what two factors?

Answer 1

diffusion (partial pressure difference) and blood flow

Question 2

How can blood still be oxygenated during strenuous exercise, when the time it remains in the pulmonary capillaries may be reduced by up to one half normal?

Answer 2

increased capillary surface area, more ideal ventilation-perfusion ratio in the upper lung, blood is normally oxygenated in the first 1/3 of the pulmonary capillary so even when the time is reduced it will still cause full oxygenation

Question 3

If cell metabolism of oxygen increases, how is interstitial Po2 affected?

Answer 3

decreases

Question 4

If blood flow increases, how is interstitial Po2 affected?

Answer 4

increases

Question 5

What is the primary difference between the diffusion of oxygen and carbon dioxide?

Answer 5

carbon dioxide can diffuse about 20 times as rapidly as oxygen

Question 6

How would decreased blood flow affect interstitial Pco2?

Answer 6

increases

Question 7

How would increased tissue metabolism affect interstitial Pco2?

Answer 7

increases

Question 8

Under normal conditions, oxygen is carried to the tissues almost entirely by ____________.

Answer 8

hemoglobin

Question 9

What is depicted on the oxygen-hemoglobin dissociation curve?

Answer 9

progressive increase in the percentage of hemoglobin bound with oxygen as blood Po2
increases, which is called the per cent saturation of hemoglobin

Question 10

Usual oxygen saturation of systemic arterial blood averages?

Answer 10

97%

Question 11

Under normal conditions, about __ mL of oxygen are transported from the lungs to the tissues by each ___ mL of blood flow.

Answer 11

5; 100 (97% to 75% hemoglobin saturation on passing through the tissue capillaries)

Question 12

What can cause up to a 20-fold increase in oxygen transport to the tissues in well trained athletes?

Answer 12

3-fold increase in oxygen delivery to tissues (oxygen dissociates from hemoglobin), 6-7 times increase in cardiac output

Question 13

The percentage of the blood that gives up its oxygen as it passes through the tissue capillaries is called the __________ ___________.

Answer 13

utilization coefficient

Question 14

What is the “oxygen buffer” function of blood hemoglobin?

Answer 14

the level of alveolar oxygen may vary greatly—from 60 to more than 500 mm Hg Po2—and still the Po2 in the peripheral tissues does not vary more than a few millimeters from normal

Question 15

Shifts the oxygen-hemoglobin dissociation curve to the right.

Answer 15

increased hydrogen ions (pH), increased CO2, increased temperature, increased 2,3 biphosphoglycerate (BPG)

Question 16

Bohr effect

Answer 16

binding of carbon dioxide with hemoglobin tends to displace oxygen

Question 17

As ADP concentration increases, rate of oxygen usage ________.

Answer 17

increases

Question 18

How is carbon dioxide transported in the blood?

Answer 18

dissolved, hemoglobin, bicarbonate (most)

Question 19

Haldane effect

Answer 19

binding of oxygen with hemoglobin tends to displace carbon dioxide

Question 20

What is the resporatory exchange ratio (R)?

Answer 20

R = rate of carbon dioxide output / rate of oxygen uptake (carb use = 1.0; fat use = 0.7, avg. is 0.825)