Question 1

If, during protein starvation, the osmotic pressure on the venous side of capillary beds drops below the hydrostatic pressure, then ________.

Accepted Answer

A)   hemoglobin will not release oxygen
B)   fluids will tend to accumulate in the interstitial fluid and tissues.
C)   the pH of the interstitial fluid will increase
D)   most carbon dioxide will be bound to hemoglobin and carried away from tissues
E)   plasma proteins will escape through the endothelium of the capillariesF) D) and E)
G) A) and B)

Question 2

A stroke volume of 70 mL/beat in a heart with a pulse of 72 beats per minute results in a cardiac output of about ________.

Accepted Answer

A)   5 liters per minute
B)   50 milliliters per minute
C)   0.5 liters per minute
D)   50 liters per minute
E)   500 liters per minuteF) A) and D)
G) B) and E)

Question 3

In mammals, gas exchange between the atmosphere and the pulmonary blood occurs in the ________.

Accepted Answer

A)   trachea
B)   larynx
C)   bronchi
D)   bronchioles
E)   alveoliF) B) and D)
G) A) and B)

Question 4

The diagnosis of hypertension in adults is based on the ________.

Accepted Answer

A)   measurement of fatty deposits on the endothelium of arteries
B)   measurement of the LDL/HDL ratio in peripheral blood
C)   percentage of blood volume made up of platelets
D)   blood pressure being greater than 140/90 mm Hg (systolic/diastolic) 
E)   number of leukocytes per cubic millimeter of bloodF) A) and D)
G) C) and D)

Question 5

The velocity of blood flow is the lowest in capillaries because ________.

Accepted Answer

A)   the capillary walls are not thin enough to allow oxygen to exchange with the cells
B)   the capillaries have internal valves that slow the flow of blood
C)   the diastolic blood pressure is too low to deliver blood to the capillaries at a high flow rate
D)   the systemic capillaries are supplied by the left ventricle, which has a lower cardiac output than the right ventricle
E)   the total cross-sectional area of the capillaries is greater than the total cross-sectional area of the arteries or any other part of the circulatory systemF) B) and D)
G) B) and C)

Question 6

At an atmospheric pressure of 870 mm Hg with 21 percent oxygen, the partial pressure of oxygen is ________.

Accepted Answer

A)   100 mm Hg
B)   127 mm Hg
C)   151 mm Hg
D)   182 mm Hg
E)   219 mm HgF) None of the above
G) A) and D)

Question 7

Atmospheric pressure at sea level is equal to a column of 760 mm Hg. Oxygen makes up 21 percent of the atmosphere by volume. The partial pressure of oxygen (PO2)  in such conditions is ________.

Accepted Answer

A)   160 mm Hg
B)   16 mm Hg
C)   120/75
D)   21/760
E)   760/21F) A) and D)
G) A) and C)

Question 8

Fick's law of diffusion describes the factors that influence the diffusion of respiratory gases across biological membranes like gills and lungs. Diffusion rate = k × A × (P2 − P1) /D. Natural selection is LEAST likely to act upon which variable in Fick's law?

Accepted Answer

A)   A
B)   k
C)   P2 − P1
D)   DE) A) and D)
F) None of the above

Question 9

Which type of bird is most likely to benefit from air sacs that reduce its weight?

Accepted Answer

A)   birds, such as geese, which migrate great distances
B)   birds that chip away wood, such as woodpeckers
C)   diving birds
D)   birds that rip apart prey, such as hawks and eaglesE) B) and C)
F) A) and B)

Question 10

The greatest difference in the concentration of respiratory gases is found in which of the following pairs of mammalian blood vessels?

Accepted Answer

A)   the pulmonary vein and the jugular vein
B)   the veins from the right and left legs
C)   the pulmonary artery and the inferior vena cava
D)   the pulmonary vein and the aorta
E)   the inferior vena cava and the superior vena cavaF) D) and E)
G) B) and D)

Question 11

The one-way flow of air along parabronchi makes what type of gas-exchange mechanism possible, at least theoretically?

Accepted Answer

A)   the same as that occurring in fish gills
B)   the same as that occurring in insect tracheae
C)   the same as that occurring in mammalian lungs
D)   the same as that occurring in echinoderm skin gillsE) B) and C)
F) A) and B)

Question 12

Circulatory systems compensate for ________.

Accepted Answer

A)   temperature differences between the lungs and the active tissue
B)   the slow rate at which diffusion occurs over large distances
C)   the problem of communication systems involving only the nervous system
D)   the need to cushion animals from trauma
E)   the need that fetal organisms have for maintaining an optimal body temperatureF) B) and C)
G) C) and D)

Question 13

Breathing is primarily regulated by ________.

Accepted Answer

A)   erythropoietin levels in the blood
B)   the concentration of red blood cells
C)   hemoglobin levels in the blood
D)   carbon dioxide concentration and pH sensors
E)   the lungs and the larynxF) A) and B)
G) B) and E)

Question 14

The aortic valve of the mammalian heart ________.

Accepted Answer

A)   is the route by which blood flows from the atria to the ventricles
B)   is found on the right side of the heart
C)   is the attachment site where the pulmonary veins empty into the heart
D)   prevents backflow of blood in the aorta
E)   is located where the anterior and posterior venae cavae empty into the heartF) A) and B)
G) B) and D)

Question 15

If a molecule of carbon dioxide enters the blood in your left toe and is exhaled from your nose, it must pass through all of the following EXCEPT ________.

Accepted Answer

A)   the pulmonary vein
B)   an alveolus
C)   the trachea
D)   the right atrium
E)   the right ventricleF) A) and C)
G) A) and E)

Question 16

Where is the velocity of blood the highest?

Accepted Answer

A)   inferior vena cava
B)   aorta
C)   small arteries
D)   superior vena cava
E)   capillariesF) A) and D)
G) C) and D)

Question 17

The Bohr shift on the oxygen-hemoglobin dissociation curve is produced by changes in ________.

Accepted Answer

A)   the partial pressure of oxygen
B)   the partial pressure of carbon monoxide
C)   hemoglobin concentration
D)   temperature
E)   pHF) None of the above
G) B) and D)

Question 18

The vertebrates in which blood flows directly from respiratory organs to body tissues without first returning to the heart are the ________.

Accepted Answer

A)   amphibians
B)   birds
C)   fishes
D)   mammals
E)   reptilesF) B) and E)
G) A) and E)

Question 19

At the summit of a high mountain, the atmospheric pressure is 380 mm Hg. If the atmosphere is still composed of 21 percent oxygen, then the partial pressure of oxygen at this altitude is about ________.

Accepted Answer

A)   0 mm Hg
B)   80 mm Hg
C)   160 mm Hg
D)   380 mm Hg
E)   760 mm HgF) A) and C)
G) B) and D)

Question 20

In what way does hemoglobin act as a buffer against changes in blood pH?

Accepted Answer

A)   Subsequent binding of oxygen is drastically reduced after the first one is bound.
B)   Hemoglobin binds some of the excess protons released by carbonic acid.
C)   Hemoglobin produces protons or hydroxide ions as needed to alter the blood pH.
D)   Hemoglobin removes excess protons from the red blood cells so that they can be excreted through the kidneys.E) B) and C)
F) All of the above

Exam 42: Gas Exchange and Circulation

The velocity of blood flow is the lowest in capillaries because ________.

Correct AnswerverifiedShow Answer

Breathing is primarily regulated by ________.

Correct AnswerverifiedShow Answer

The aortic valve of the mammalian heart ________.

Correct AnswerverifiedShow Answer

Atmospheric pressure at sea level is equal to a column of 760 mm Hg. Oxygen makes up 21 percent of the atmosphere by volume. The partial pressure of oxygen (PO2) in such conditions is ________.

Correct AnswerverifiedShow Answer

Where is the velocity of blood the highest?

Correct AnswerverifiedShow Answer

At an atmospheric pressure of 870 mm Hg with 21 percent oxygen, the partial pressure of oxygen is ________.

Correct AnswerverifiedShow Answer

The vertebrates in which blood flows directly from respiratory organs to body tissues without first returning to the heart are the ________.

Correct AnswerverifiedShow Answer

In what way does hemoglobin act as a buffer against changes in blood pH?

Correct AnswerverifiedShow Answer

The Bohr shift on the oxygen-hemoglobin dissociation curve is produced by changes in ________.

Correct AnswerverifiedShow Answer

The one-way flow of air along parabronchi makes what type of gas-exchange mechanism possible, at least theoretically?

Correct AnswerverifiedShow Answer

A stroke volume of 70 mL/beat in a heart with a pulse of 72 beats per minute results in a cardiac output of about ________.

Correct AnswerverifiedShow Answer

In mammals, gas exchange between the atmosphere and the pulmonary blood occurs in the ________.

Correct AnswerverifiedShow Answer

If, during protein starvation, the osmotic pressure on the venous side of capillary beds drops below the hydrostatic pressure, then ________.

Correct AnswerverifiedShow Answer

At the summit of a high mountain, the atmospheric pressure is 380 mm Hg. If the atmosphere is still composed of 21 percent oxygen, then the partial pressure of oxygen at this altitude is about ________.

Correct AnswerverifiedShow Answer

Fick's law of diffusion describes the factors that influence the diffusion of respiratory gases across biological membranes like gills and lungs. Diffusion rate = k × A × (P2 − P1) /D. Natural selection is LEAST likely to act upon which variable in Fick's law?

Correct AnswerverifiedShow Answer

If a molecule of carbon dioxide enters the blood in your left toe and is exhaled from your nose, it must pass through all of the following EXCEPT ________.

Correct AnswerverifiedShow Answer

The diagnosis of hypertension in adults is based on the ________.

Correct AnswerverifiedShow Answer

Which type of bird is most likely to benefit from air sacs that reduce its weight?

Correct AnswerverifiedShow Answer

Circulatory systems compensate for ________.

Correct AnswerverifiedShow Answer

The greatest difference in the concentration of respiratory gases is found in which of the following pairs of mammalian blood vessels?

Correct AnswerverifiedShow Answer

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