Deck 37: Gas Exchange & Transport

Question 1

Each hemoglobin molecule can carry how many oxygen molecules?

A) One
B) Two
C) Four
D) Eight

Answer 1

C

Question 2

Dalton law states that the partial pressure of a gas in a mixture of gases is _____ to the total pressure of the mixture.

A) inversely related to the concentration of that gas in the mixture and
B) directly related to the concentration of that gas in the mixture and
C) directly related to the concentration of that gas in the mixture and inversely related
D) inversely related to the concentration of that gas in the mixture and directly related

Answer 2

B

Question 3

The major form by which carbon dioxide is transported in the circulatory system is:

A) in solution.
B) as bicarbonate ions.
C) as carbaminohemoglobin.
D) none of the above.

Answer 3

B

Question 4

One hundred milliliters of arterial blood contains approximately what volume percent of oxygen?

A) 10%
B) 15%
C) 20%
D) 25%

Question 5

The PCO₂ in alveolar air is _____ blood.

A) less than in the systemic venous
B) greater than in the systemic venous
C) equal to the systemic arterial
D) Both A and C are correct.

Question 6

Because of tissue layers between alveolar air and the blood supply, arterial blood PO₂ is always less than alveolar PO₂.

Question 7

By the time the blood leaves the lung capillaries to return to the heart, what percentage of the blood's hemoglobin has united with oxygen?

A) 55%
B) 63%
C) 82%
D) 97%

Question 8

A drop in the body's production of carbonic anhydrase would hinder the formation of:

A) carbonic acid.
B) oxyhemoglobin.
C) carbaminohemoglobin.
D) All of the above are correct.

Question 9

The partial pressure exerted by oxygen in a liquid is called oxygen tension.

Question 10

Which of the following would have the greatest accelerating effect on the dissociation of oxygen from hemoglobin?

A) Increased PO₂
B) Decreased PCO₂
C) Decreased PO₂ and decreased PCO₂
D) Decreased PO₂ and increased PCO₂

Question 11

If anything decreases alveolar PO₂, how does that affect the alveolar-blood oxygen pressure gradient?

A) Anything that decreases alveolar PO₂ tends to increase the alveolar-blood oxygen pressure gradient and, therefore, tends to increase the amount of oxygen entering the blood.
B) Anything that decreases alveolar PO₂ tends to decrease the alveolar-blood oxygen pressure gradient and, therefore, tends to decrease the amount of oxygen entering the blood.
C) Anything that decreases alveolar PO₂ tends to increase the alveolar-blood diffusion rate and, therefore, tends to increase the amount of oxygen entering the blood.
D) Anything that decreases PO₂ tends to increase arterial-blood PO₂ and, therefore, tends to decrease the amount of oxygen entering the blood.

Question 12

If a person were skiing high up in the mountains, she might feel that she is having trouble breathing (getting enough oxygen in her blood). This is because the:

A) thoracic cavity has a difficult time lowering the internal pressure below the lower atmospheric pressure.
B) lower atmospheric pressure lowers the PO₂ and the diffusion gradient between the blood and the atmosphere is less.
C) lower atmospheric pressure lowers the PO₂ and the diffusion gradient between the blood and the atmosphere is greater.
D) physiological dead air space increases and atmospheric pressure decreases.

Question 13

The approximate partial pressure of oxygen at standard atmospheric pressure is about _____ mm Hg.

A) 23
B) 160
C) 300
D) 590

Question 14

The partial pressure of oxygen in an artery is always lower than the partial pressure of oxygen in a vein.

Question 15

The PCO₂ in the atmosphere is:

A) less than in the alveolar air.
B) greater than in the alveolar air.
C) equal to the alveolar air.
D) greater than arterial blood.

Question 16

Carbon dioxide is carried in three forms in the blood. Ranking them from greatest to least amount carried, the sequence would be:

A) dissolved in the plasma, carbaminohemoglobin, and bicarbonate ion.
B) carbaminohemoglobin, bicarbonate ion, and dissolved in plasma.
C) bicarbonate ion, dissolved in plasma, and carbaminohemoglobin.
D) bicarbonate ion, carbaminohemoglobin, and dissolved in plasma.

Question 17

Each hemoglobin molecule can carry how many carbon dioxide molecules?

A) Two
B) Four
C) Eight
D) Hemoglobin cannot carry carbon dioxide molecules.

Question 18

The symbol HbNCOOH- is used for:

A) carbonic anhydrase.
B) carbaminohemoglobin.
C) the heme group.
D) the bicarbonate ion.

Question 19

Which of the following helps determine the amount of oxygen that diffuses into the blood each minute?

A) The total functional surface area of the respiratory membrane
B) Alveolar ventilation
C) The oxygen pressure gradient between alveolar air and incoming pulmonary blood
D) All of the above help determine the amount of oxygen that diffuses into the blood each minute.

Question 20

Which of the following is not a means of transporting oxygen in the blood?

A) As oxyhemoglobin
B) Combined with the bicarbonate ion (HCO3-)
C) Dissolved in the plasma
D) All of the above are used to transport oxygen in the blood.

Question 21

In the lung as the partial pressure of oxygen of the blood goes up, the partial pressure of oxygen in the alveolar air goes down proportionally.

Question 22

About 20% of the carbon dioxide that is carried in the blood is carried on hemoglobin attached to the acid group of an amino acid.

Question 23

The terms oxygen partial pressure and oxygen tension are interchangeable.

Question 24

Under usual conditions, the oxygen saturation of systemic venous blood is 75%.

Question 25

Under usual conditions, the partial pressure of oxygen in systemic venous blood is approximately 87 mm Hg.

Question 26

In the lung oxygen moves down its pressure gradient, whereas carbon dioxide moves up its pressure gradient.

Question 27

If the PCO₂ is greater in the cells than in the intercellular fluid, CO₂ will remain in the cells.

Question 28

The partial pressure of oxygen in the alveolar air is equal to the partial pressure of oxygen in the systemic venous blood.

Question 29

An increase in the plasma PCO₂ and a decrease in PO₂ cause an increase in the dissociation of CO₂ from hemoglobin.

Question 30

Iron is important in hemoglobin because it carries oxygen to the cells and carbon dioxide away from the cells.

Question 31

The PO₂ is higher in the femoral artery than in the femoral vein.

Question 32

On a percentage basis, there is more carbon dioxide dissolved in the plasma than there is oxygen dissolved in the plasma.

Question 33

The Bohr effect describes the effect of an increased PCO₂ causing a decreased affinity between hemoglobin and oxygen.

Question 34

For cells to get oxygen, they must have an oxygen partial pressure lower than the arterial blood serving them.

Question 35

When cells increase the rate of oxygen usage, there is an increase in the delivery of oxygen to the cells.

Question 36

Oxygenated blood contains equal amounts of both dissolved oxygen and oxygen combined with hemoglobin.

Question 37

One reason that carbon monoxide gas is so dangerous is that it attaches to hemoglobin more readily than does oxygen gas.

Question 38

There are six iron atoms in a single hemoglobin molecule.

Question 39

One factor that determines the amount of oxygen transferred from the lungs to the blood is the total functional surface area of the respiratory membrane.

Question 40

Blood is distributed through the capillaries in a layer so thin that each red blood cell comes in contact with the alveolar-capillary membrane.

Question 41

The chloride shift is an important step of oxygen transport in the blood.

Question 42

An increase in carbon dioxide would have the opposite effect on oxygen-hemoglobin dissociation than would a drop in blood pH.

Question 43

White blood cells do not have a role in oxygen transport.

Question 44

The transport of carbon dioxide will tend to lower blood pH.

Question 45

The Bohr effect explains what happens to oxygen, whereas the Haldane effect explains what happens to carbon dioxide.

Question 46

In a resting person, the oxygen saturation in the systemic venous blood is still about 50%.

Question 47

About 10% of the carbon dioxide carried in the blood is simply dissolved in the plasma.

Question 48

The formation of carbaminohemoglobin is a reversible reaction.

Question 49

To produce the highest possible oxygen concentration in the blood, gas exchange occurs in only one direction at the respiratory membrane-from the lung to the blood.

Question 50

In order for the cells to get the correct amount of oxygen, the oxygen level in the interstitial fluid must be less than that of the cells.

Question 51

The presence of hemoglobin in the blood approximately doubles the oxygen-carrying capacity of plasma alone.

Question 52

Hemoglobin is made up of four polypeptide chains: an alpha, a beta, a gamma, and a delta.

Question 53

According to the rate laws of chemistry, the more carbon dioxide in the blood, the more carbaminohemoglobin will be formed.

Question 54

Carbonic acid forms when carbon dioxide reacts with water in the blood plasma.

Question 55

Although interstitial fluid and intracellular fluid oxygen partial pressure values are not definitely established, they are known to stay within a very narrow range.

Question 56

An increase in the partial pressure of carbon dioxide decreases the affinity between hemoglobin and oxygen. This is called a right shift, or the Haldane effect.

Question 57

Hemoglobin is a quaternary protein consisting of four tertiary polypeptide chains.

Question 58

Hemoglobin can carry oxygen more efficiently than it can carry carbon dioxide because all four polypeptide chains can carry oxygen, but only the beta chain can carry carbon dioxide.

Question 59

There is one iron atom in one heme group.

Question 60

The enzyme in blood plasma that helps form carbaminohemoglobin is carbonic anhydrase.

Question 61

Increased cellular activity would decrease the carbon dioxide gradient between the cells and the arterial blood.

Question 62

Explain the process by which oxygen is transported by the blood.

Question 63

Briefly describe and diagram the oxygen-hemoglobin dissociation curve.

Question 64

Explain the process by which carbon dioxide is transported by the blood.

Question 65

Explain why less oxygen would enter the blood at a high altitude than would enter the blood at sea level.

Question 66

Explain Dalton law as it relates to the movement of oxygen from the lungs into the circulatory system.

Question 67

Identify the major factors that help determine the amount of oxygen that diffuses into the blood each minute.

Question 68

Increased cellular activity would increase the oxygen gradient between the cells and the arterial blood.

Question 69

The structural designs of alveoli and capillaries in lung tissue are such that they facilitate oxygen diffusion. List examples that support the concept that structure determines function.

Question 70

Assume the percent of oxygen in the air is constant (about 21%). What is the partial pressure of oxygen in the mountains, where the atmospheric pressure is 725 mm Hg?