Question 1

The walls of large _______ have elastic fibers and can withstand high pressures.

Accepted Answer

The answer of The walls of large _______ have elastic...

Question 2

The production of erythrocytes

Accepted Answer

A)   ceases if the hematocrit falls below normal.
B)   is stimulated by erythropoietin.
C)   is about equal to the production of white blood cells.
D)   is inhibited by prothrombin.
E)   occurs in bone marrow before birth and in lymph nodes after birth.F) A) and B)
G) A) and C)

Question 3

The primary pacemaker of the heart is the _______ at the junction of the superior vena cava and right atrium.

Accepted Answer

The answer of The primary pacemaker of the heart is...

Question 4

Which of the following statements about the control of circulation in humans is false?

Accepted Answer

A)   Sympathetic nerve input to skeletal muscle causes the blood vessels in the muscle to dilate.
B)   Blood flow can be regulated by autonomic nerve signals emanating from cardiovascular control centers in the medulla of the brain.
C)   Carotid artery chemoreceptors detect low O2 levels in the blood and promote increased blood pressure.
D)   Hormones such as angiotensin and vasopressin cause venules to constrict.
E)   Autoregulatory mechanisms can cause constriction or dilation of arterioles.F) C) and D)
G) None of the above

Question 5

Which of the following is an example of an animal with an open circulatory system?

Accepted Answer

A)   Bat
B)   Earthworm
C)   Hydra
D)   Snail
E)   LizardF) None of the above
G) A) and D)

Question 6

Gap junctions

Accepted Answer

A)   electrically isolate cardiac muscle cells.
B)   allow large numbers of cardiac muscle cells to contract in unison.
C)   provide enough strength to withstand the large pressure generated by the ventricles.
D)   are found only in the cardiac muscle cells of the ventricles.
E)   are especially abundant in the muscles between the atria and ventricles.F) A) and D)
G) B) and E)

Question 7

Which of the following hormones causes constriction of the blood vessels?

Accepted Answer

A)   Epinephrine
B)   Angiotensin
C)   Acetylcholine
D)   Both a and b
E)   All of the aboveF) A) and B)
G) All of the above

Question 8

Which statement about the human heart is true?

Accepted Answer

A)   The walls of the right ventricle are thicker than the walls of the left ventricle.
B)   Blood flowing through atrioventricular valves is always deoxygenated blood.
C)   The second heart sound is due to the closing of the aortic valve.
D)   Blood returns to the heart from the lungs in the vena cava.
E)   During systole, the aortic valve is open and the pulmonary valve is closed.F) B) and C)
G) A) and B)

Question 9

Which of the following statements about vertebrate circulatory systems is false?

Accepted Answer

A)   Crocodilians have a four-chambered heart.
B)   In birds and mammals, pressures in the pulmonary circuit are lower than those in the systemic circuit.
C)   The ventricle of turtles, snakes, and lizards is partly divided by a septum.
D)   Amphibians have two atria and one ventricle.
E)   In fishes, blood passes through the gills, returns to the heart, and then is pumped to the body.F) A) and D)
G) A) and E)

Question 10

As compared to the circulatory system of most fishes, the circulatory system of adult amphibians has the advantage of

Accepted Answer

A)   a four-chambered heart.
B)   heart metamorphosis.
C)   a partial separation between pulmonary and systemic circulation.
D)   a pocket of the gut that serves as an air bladder.
E)   separation between oxygenated and deoxygenated blood.F) B) and C)
G) B) and D)

Question 11

Which of the following is present in veins, but not arteries?

Accepted Answer

A)   Valves
B)   Pumps
C)   Endothelium
D)   Smooth muscle tissue
E)   SphinctersF) A) and C)
G) B) and D)

Question 12

Refer to the graph below, which depicts blood pressure, blood velocity, and the area of the blood vessels throughout a circulatory system. Which of the following statements is false?

Accepted Answer

A)   Curve 1 traces blood velocity; curve 2 traces blood pressure; curve 3 traces blood vessel area.
B)   Curve 3 is at its maximum point in the capillaries.
C)   The vessels represented on the left of the graph have many extracellular collagen and elastin fibers in their walls.
D)   The vessels on the left of the graph are referred to as resistance vessels.
E)   Exchanges of nutrients, respiratory gases, and hormones occur where curve 3 is at its maximum point.F) A) and D)
G) A) and C)

Question 13

The blood vessels with the greatest total cross-sectional area are the

Accepted Answer

A)   arteries.
B)   arterioles.
C)   capillaries.
D)   venules.
E)   veins.F) A) and C)
G) A) and D)

Question 14

A platelet is activated to initiate clotting

Accepted Answer

A)   during a histamine reaction.
B)   when leukocytes are activated.
C)   when collagen fibers are encountered.
D)   when blood flow rates drop.
E)   in the presence of prothrombin.F) A) and B)
G) C) and D)

Question 15

Blood consists of a fluid fraction consisting of _______ and a solid fraction consisting of _______.

Accepted Answer

A)   plasma; water, erythrocytes, and platelets
B)   erythrocytes; leukocytes, macrophages, and platelets
C)   plasma; erythrocytes, platelets, and leukocytes
D)   leukocytes; erythrocytes and platelets
E)   interstitial fluid; stem cellsF) A) and B)
G) A) and C)

Question 16

Which of the following does not control the cardiac cycle?

Accepted Answer

A)   Aortic valve
B)   Sinoatrial node
C)   Atrioventricular node
D)   Bundle of His
E)   Purkinje fibersF) All of the above
G) None of the above

Question 17

Crocodilians differ from other reptiles in that they have

Accepted Answer

A)   separate pulmonary circulation.
B)   lungs and no gills.
C)   an open circulatory system.
D)   more muscular atria.
E)   a four-chambered heart.F) All of the above
G) B) and D)

Question 18

During the cardiac cycle, the blood pressure in the aorta is at a minimum

Accepted Answer

A)   at the end of systole.
B)   at the beginning of systole.
C)   at the beginning of diastole.
D)   when the physician hears the "dub" sound with the stethoscope.
E)   None of the aboveF) A) and B)
G) D) and E)

Question 19

The complexity and number of chambers in the heart increases from fishes to amphibians to reptiles to mammals and birds. An important consequence of this increased complexity is the gradual separation of the circulatory system into two independent circuits: the _______ and the _______.

Accepted Answer

The answer of The complexity and number of chambers in...

Question 20

Some large, multicellular, aquatic animals have no circulatory system. They manage gas exchange

Accepted Answer

A)   by bringing the external environment (with its supply of oxygen)  inside their body.
B)   by means of endosymbiotic bacteria that produce oxygen inside their tissues.
C)   solely by diffusion from outside their bodies.
D)   by basking at the surface periodically to allow for diffusion of oxygen.
E)   None of the aboveF) None of the above
G) B) and D)

Exam 50: Circulatory Systems

During the cardiac cycle, the blood pressure in the aorta is at a minimum

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Which statement about the human heart is true?

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Which of the following hormones causes constriction of the blood vessels?

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Refer to the graph below, which depicts blood pressure, blood velocity, and the area of the blood vessels throughout a circulatory system. Which of the following statements is false?

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The blood vessels with the greatest total cross-sectional area are the

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Which of the following statements about vertebrate circulatory systems is false?

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Which of the following does not control the cardiac cycle?

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Blood consists of a fluid fraction consisting of _______ and a solid fraction consisting of _______.

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A platelet is activated to initiate clotting

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As compared to the circulatory system of most fishes, the circulatory system of adult amphibians has the advantage of

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The production of erythrocytes

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Gap junctions

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Which of the following statements about the control of circulation in humans is false?

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The complexity and number of chambers in the heart increases from fishes to amphibians to reptiles to mammals and birds. An important consequence of this increased complexity is the gradual separation of the circulatory system into two independent circuits: the _______ and the _______.

Correct AnswerverifiedShow Answer

Crocodilians differ from other reptiles in that they have

Correct AnswerverifiedShow Answer

Some large, multicellular, aquatic animals have no circulatory system. They manage gas exchange

Correct AnswerverifiedShow Answer

The walls of large _______ have elastic fibers and can withstand high pressures.

Correct AnswerverifiedShow Answer

The primary pacemaker of the heart is the _______ at the junction of the superior vena cava and right atrium.

Correct AnswerverifiedShow Answer

Which of the following is an example of an animal with an open circulatory system?

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Which of the following is present in veins, but not arteries?

Correct AnswerverifiedShow Answer

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Blood consists of a fluid fraction consisting of _ and a solid fraction consisting of _.

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The complexity and number of chambers in the heart increases from fishes to amphibians to reptiles to mammals and birds. An important consequence of this increased complexity is the gradual separation of the circulatory system into two independent circuits: the _ and the _.

Correct Answer
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