Gas Exhange

Question 1

What is the PO2 in the alveoli?

Answer 1

100 mmHg

Question 2

What is the PO2 in the pulmonary artery?

Answer 2

40 mmHg

Question 3

What diffuses from the alveoli into the blood?

Answer 3

Oxygen

Question 4

What is the PCO2 in the alveoli?

Answer 4

40 mmHg

Question 5

What is the PCO2 in the pulmonary artery?

Answer 5

45 – 46 mmHg

Question 6

What diffuses from blood into the alveoli?

Answer 6

CO2

Question 7

What is the PO2 of blood in the arterial end of capillary?

Answer 7

100 mmHg

Question 8

What is the PO2 in the ISF around tissues?

Answer 8

40 mmHg

Question 9

What diffuses from blood into the tissues?

Answer 9

Oxygen

Question 10

What is the PCO2 of blood in the arterial end of capillary?

Answer 10

40 mmHg

Question 11

What is the PCO2 in the ISF around the tissues?

Answer 11

45 mmHg

Question 12

What diffuses from the tissues into blood?

Answer 12

CO2

Question 13

What is the normal PO2 and PCO2 at the venous end of capillaries?

Answer 13

PO2 = 40, PCO2 = 45

Question 14

What is the PO2 and PCO2 during normal metabolism with increased blood flow?

Answer 14

PO2 = 60, PCO2 < 45

Question 15

What is the PO2 and PCO2 during increased metabolism with normal blood flow?

Answer 15

PO2 = 20, PCO2 = 55

Question 16

What percentage of oxygen is transported by hemoglobin (Hb)?

Answer 16

97%

Question 17

What is each Hb molecule composed of?

Answer 17

Four globin subunits (two α and two β) and four heme subunits

Question 18

How many O2 molecules can each Hb molecule bind?

Answer 18

Four O2 molecules reversibly

Question 19

What is the normal level of Hb in blood?

Answer 19

15 grams/100 ml blood

Question 20

How much O2 can be carried by Hb for each 100 ml of blood?

Answer 20

20 ml of O2

Question 21

What is the oxygen carrying capacity of an anemic person with Hb level of 10?

Answer 21

13.4 ml of O2 can be carried by Hb/100 ml of blood

Question 22

What is the solubility of oxygen in plasma?

Answer 22

0.003 ml O2/100 ml blood/mmHg

Question 23

What is the PO2 in the systemic arteries?

Answer 23

100 mmHg

Question 24

What is the dissolved O2 in arterial blood?

Answer 24

0.3 ml O2/100 ml of blood

Question 25

What is the normal rate of O2 consumption by tissues?

Answer 25

250 ml O2/min

Question 26

What is the required blood flow to meet normal O2 consumption rate if relying solely on dissolved O2?

Answer 26

83 L/min

Question 27

What is the normal blood flow (cardiac output)?

Answer 27

5 L/min

Question 28

What is the relationship between PO2 and dissolved O2?

Answer 28

There is a direct relationship

Question 29

What is the X-axis of the hemoglobin dissociation curve?

Answer 29

Partial pressure of oxygen

Question 30

What is the Y-axis of the hemoglobin dissociation curve?

Answer 30

Hemoglobin saturation

Question 31

What is the oxygen content at the arterial end of capillary?

Answer 31

20 ml/dl

Question 32

What is the oxygen content at the venous end of capillary?

Answer 32

15 ml/dl

Question 33

What is the oxygen consumption calculated from arterial and venous oxygen content?

Answer 33

5 ml/dl

Question 34

What happens to the Hb dissociation curve in carbon monoxide (CO) poisoning?

Answer 34

It shifts to the left

Question 35

What is the affinity of CO to Hb compared to O2?

Answer 35

About 250 times greater

Question 36

What is the oxygen content of Hb at the arterial end of capillary in CO poisoning?

Answer 36

10 ml/dl

Question 37

What is the oxygen consumption in CO poisoning?

Answer 37

Zero (tissue hypoxia)

Question 38

What is the Haldane effect?

Answer 38

↑PO2 at lung level ↑ CO2 release from Hb

Question 39

What is the Bohr effect?

Answer 39

↑PCO2 & H+ at tissue level ↑ O2 release from Hb

Question 40

What factors shift the hemoglobin dissociation curve to the right?

Answer 40

Increased PCO2, increased temperature, increased 2,3-DPG, decreased pH level

Question 41

What factors shift the hemoglobin dissociation curve to the left?

Answer 41

Decreased PCO2, decreased temperature, decreased 2,3-DPG, increased pH level