Question 1

The semilunar valves of the mammalian heart
A)are the route by which blood flows from the atria to the ventricles.
B)are found only on the right side of the heart.
C)are the attachment sites where the pulmonary veins empty into the heart.
D)are able to prevent backflow of blood in the aorta and pulmonary arteries.

Accepted Answer

The semilunar valves are located at the base of the aorta and pulmonary arteries, and prevent backflow of blood from these vessels into the ventricles during diastole. They are not the route by which blood flows from the atria to the ventricles, and are found on both sides of the heart. They are not attachment sites for the pulmonary veins.

Question 2

A patient with a blood pressure of 120/75,a pulse rate of 40 beats/minute,a stroke volume of 70 mL/beat,and a respiratory rate of 25 breaths/minute will have a cardiac output of
A)500 mL/minute.
B)1,000 mL/minute.
C)1,750 mL/minute.
D)2,800 mL/minute.
E)4,800 mL/minute.

Accepted Answer

Cardiac output is calculated as the product of heart rate (pulse rate) and stroke volume. For this patient, it is 40 beats/minute * 70 mL/beat = 2,800 mL/minute.

Question 3

Gas exchange in the aquatic salamander known as the axolotl is correctly described as
A)active transport to move oxygen into the salamander from the water.
B)facilitated diffusion to move oxygen into the salamander from the water.
C)facilitated diffusion of carbon dioxide from the salamander into the water.
D)simple diffusion of oxygen into the salamander from the water.
E)active transport of carbon dioxide from the salamander into the water.

Accepted Answer

Gas exchange in axolotls occurs through simple diffusion as oxygen diffuses from the water into the salamander's bloodstream and carbon dioxide diffuses out of the bloodstream into the water. There is no active transport or facilitated diffusion involved in this process.

Question 4

Circulatory systems compensate for
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 between the nervous system and respiratory system.
D)the need fetal organisms have for maintaining an optimal body temperature.

Accepted Answer

Circulatory systems compensate for the slow rate at which diffusion occurs over large distances by transporting gases, nutrients, and waste products throughout the body. This allows for more efficient and rapid delivery of these substances to active tissues.

Question 5

The set of blood vessels with the slowest velocity of blood flow is
A)the arteries.
B)the arterioles.
C)the venules.
D)the capillaries.
E)the veins.

Accepted Answer

Capillaries have the slowest velocity of blood flow because their small diameter restricts the passage of red blood cells, causing them to move through in a single-file line. This allows for more efficient exchange of nutrients and gases between the blood and surrounding tissues.

Question 6

Kevin is sitting quietly at home reading his biology textbook.His stroke volume is 70 mL per beat,and his resting heart rate is 60 beats per minute.What is Kevin's cardiac output?
A)4.2 L/minute
B)4.2 mL/minute
C)0.42 L/minute
D)42 L/minute
E)420 L/minute

Accepted Answer

Cardiac output is calculated by multiplying stroke volume by heart rate. For Kevin, this is 70 mL/beat * 60 beats/minute = 4200 mL/minute, which is equal to 4.2 L/minute.

Question 7

Hemolymph is found in the circulatory system of what kind of animal?
A)grasshopper
B)dog
C)eagle
D)earthworm

Accepted Answer

Hemolymph is the circulatory fluid found in the circulatory system of insects such as grasshoppers. It is not found in dogs, eagles, or earthworms.

Question 8

The only vertebrates in which blood flows directly from respiratory organs to body tissues without first returning to the heart are the
A)amphibians.
B)birds.
C)fishes.
D)mammals.
E)reptiles.

Accepted Answer

Fishes have a single circulatory system in which blood flows in a single loop from the heart to the gills, where it is oxygenated, and then directly to the body tissues before returning to the heart. This is known as a "single circulation" system. In contrast, all other vertebrates have a "double circulation" system in which blood flows from the heart to the lungs or gills for oxygenation before returning to the heart and being pumped out to the body tissues.

Question 9

Organisms with a circulating bodily fluid that is distinct from the fluid that directly surrounds the body's cells are likely to have
A)an open circulatory system.
B)a closed circulatory system.

Accepted Answer

Organisms with a circulating bodily fluid that is distinct from the fluid that directly surrounds the body's cells have a closed circulatory system. In a closed circulatory system, the circulating fluid, or blood, is contained within vessels and is separate from the interstitial fluid that surrounds the body's cells. This allows for more efficient delivery of oxygen and nutrients to the cells, as well as more effective removal of waste products. Open circulatory systems, on the other hand, have a body fluid that directly bathes the tissues and organs, and is not contained within vessels.

Question 10

Which of the following develops the greatest pressure on the blood in the mammalian aorta?
A)systole of the left atrium
B)diastole of the right ventricle
C)systole of the left ventricle
D)diastole of the right atrium
E)systole of the right ventricle

Accepted Answer

The systole of the left ventricle is when the largest volume of blood is ejected from the heart into the aorta. This results in the highest pressure within the aorta, making option C the correct choice.

Question 11

To adjust blood pressure independently in the capillaries of the gas-exchange surface and in the capillaries of the general body circulation,an organism would need a(n)
A)open circulatory system.
B)closed circulatory system.
C)lymphatic system.
D)two-chambered heart.
E)four-chambered heart.

Accepted Answer

The four-chambered heart allows for the separation of oxygenated and deoxygenated blood, allowing for independent control of blood pressure in different areas of the body. This is essential for organisms with high metabolic demands, such as birds and mammals, which require high blood pressure in the gas-exchange surface to optimize oxygen uptake and delivery, but lower blood pressure in the general circulation to prevent damage to organs and tissues. Open and closed circulatory systems lack the necessary separation of oxygenated and deoxygenated blood, while the lymphatic system is not directly involved in blood pressure regulation. Two-chambered hearts also lack the necessary separation of blood and are primarily found in fish.

Question 12

Edema,or swelling,is a potentially serious medical issue where a significant increase in the amount of interstitial fluid surrounding cells and tissues occurs.If edema were to occur in the interstitial fluid surrounding the capillary beds of a human's lungs,what is the most likely outcome?
A)an increase in the amount of carbon dioxide moving from the blood to the lungs
B)an increase in the amount of oxygen moving from the lungs into the blood
C)a decrease in the amount of oxygen moving from the lungs into the blood
D)an increase of pressure that would cause the capillary beds to burst
E)a decrease in the amount of work needed for effective ventilation of the lungs

Accepted Answer

Edema in the interstitial fluid surrounding the capillary beds of the lungs would increase the distance between the alveoli and the capillaries, making it more difficult for oxygen to diffuse across that distance. This would therefore decrease the amount of oxygen moving from the lungs into the blood.

Question 13

A human red blood cell is in an artery of the left arm and is on its way to deliver oxygen to a cell in the left thumb.To travel from the artery in the left arm to the cell in the left thumb,this red blood cell must pass through
A)one capillary bed.
B)two capillary beds.
C)three capillary beds.
D)four capillary beds.

Accepted Answer

Oxygen delivery from an artery in the arm to a cell in the thumb involves passing through only one capillary bed, where the exchange of oxygen and carbon dioxide occurs.

Question 14

Which of the following is the correct sequence of blood flow in reptiles and mammals?
A)left ventricle → aorta → lungs → systemic circulation
B)right ventricle → pulmonary vein → pulmocutaneous circulation
C)pulmonary vein → left atrium → left ventricle → pulmonary circuit
D)vena cava → right atrium → right ventricle → pulmonary circuit
E)right atrium → pulmonary artery → left atrium → ventricle

Accepted Answer

The correct sequence of blood flow in reptiles and mammals starts with the vena cava, which brings deoxygenated blood into the right atrium. From the right atrium, the blood moves to the right ventricle, and then it is pumped into the pulmonary circuit (lungs in mammals, and lungs or skin in reptiles) for oxygenation. This sequence accurately describes the initial stages of systemic circulation, emphasizing the role of the right heart chambers in pumping deoxygenated blood to the lungs or skin for oxygenation.

Question 15

Damage to the sinoatrial node in humans
A)is a major contributor to heart attacks.
B)would block conductance between the bundle branches and the Purkinje fibers.
C)would cause blood flow rate to increase.
D)would disrupt the rate and timing of cardiac muscle contractions.
E)would have a direct effect on blood pressure monitors in the aorta.

Accepted Answer

Damage to the sinoatrial node would disrupt the normal pacemaker function of the heart, leading to irregular heartbeats and potentially causing arrhythmias. This would affect the timing and rate of cardiac muscle contractions, impacting the heart's ability to efficiently pump blood throughout the body. Damage to the sinoatrial node is not a major contributor to heart attacks nor does it have a direct effect on blood pressure monitors. Blockage of conductance between bundle branches and Purkinje fibers is related to bundle branch block, which is a different condition. Increased blood flow rate is not directly related to sinoatrial node damage.

Question 16

Heart rate will increase in the presence of increased
A)apolipoproteins.
B)immunoglobulins.
C)erythropoietin.
D)epinephrine.
E)platelets.

Accepted Answer

Epinephrine is a hormone that is released by the adrenal glands during times of stress and causes an increase in heart rate. This response is part of the body's fight or flight response and helps to mobilize energy resources in response to perceived danger.

Question 17

All of the following are present in arterioles and in capillaries except
A)fully oxygenated blood.
B)plasma in which carbon dioxide has been added.
C)a lining of endothelial cells.
D)circular smooth muscle cells.
E)white blood cells and platelets.

Accepted Answer

Arterioles contain circular smooth muscle cells in their walls which allow for the regulation of blood flow and pressure. Capillaries, however, lack these smooth muscle cells; they are primarily composed of a thin layer of endothelial cells to facilitate the exchange of gases, nutrients, and waste products between blood and tissues.

Question 18

Why has natural selection favored the evolution of double circulation in birds and mammals?
A)because they are larger than reptiles and amphibians
B)because they use more energy than equivalent-size reptiles and amphibians
C)because they have more viscous blood than reptiles and amphibians
D)because they cannot obtain as much oxygen from the air as reptiles and amphibians

Accepted Answer

Birds and mammals are endothermic animals that use more energy than equivalent-size reptiles and amphibians. This high metabolic demand requires an efficient delivery of oxygen and nutrients to the body's tissues and the removal of metabolic waste. The double circulation allows for a separation of the oxygen-rich blood and oxygen-poor blood, leading to better oxygen delivery and higher energy output.

Question 19

The set of blood vessels with the lowest blood pressure driving flow is
A)the arteries.
B)the arterioles.
C)the venules.
D)the capillaries.
E)the veins.

Accepted Answer

Veins have the lowest blood pressure compared to other segments of the circulatory system. This is because they are further away from the heart and closer to the return of blood to the heart, where the pressure has significantly decreased after passing through the systemic circulation.

Question 20

In which of the following organisms does blood flow from the pulmocutaneous circulation to the heart before circulating through the rest of the body?
A)annelids
B)molluscs
C)fishes
D)frogs
E)insects

Accepted Answer

Frogs have a unique circulatory system where blood flows from the pulmocutaneous circulation (lungs and skin) to the heart before being pumped to the rest of the body. This is part of their dual circulation system, which is different from the single circulation found in fish or the open circulatory systems of insects, annelids, and some molluscs.

Quiz 34: Circulation and Gas Exchange

The semilunar valves of the mammalian heart

A patient with a blood pressure of 120/75,a pulse rate of 40 beats/minute,a stroke volume of 70 mL/beat,and a respiratory rate of 25 breaths/minute will have a cardiac output of

Gas exchange in the aquatic salamander known as the axolotl is correctly described as

Circulatory systems compensate for

The set of blood vessels with the slowest velocity of blood flow is

Kevin is sitting quietly at home reading his biology textbook.His stroke volume is 70 mL per beat,and his resting heart rate is 60 beats per minute.What is Kevin's cardiac output?

Hemolymph is found in the circulatory system of what kind of animal?

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

Organisms with a circulating bodily fluid that is distinct from the fluid that directly surrounds the body's cells are likely to have

Which of the following develops the greatest pressure on the blood in the mammalian aorta?

To adjust blood pressure independently in the capillaries of the gas-exchange surface and in the capillaries of the general body circulation,an organism would need a(n)

Edema,or swelling,is a potentially serious medical issue where a significant increase in the amount of interstitial fluid surrounding cells and tissues occurs.If edema were to occur in the interstitial fluid surrounding the capillary beds of a human's lungs,what is the most likely outcome?

A human red blood cell is in an artery of the left arm and is on its way to deliver oxygen to a cell in the left thumb.To travel from the artery in the left arm to the cell in the left thumb,this red blood cell must pass through

Which of the following is the correct sequence of blood flow in reptiles and mammals?

Damage to the sinoatrial node in humans

Heart rate will increase in the presence of increased

All of the following are present in arterioles and in capillaries except

Why has natural selection favored the evolution of double circulation in birds and mammals?

The set of blood vessels with the lowest blood pressure driving flow is

In which of the following organisms does blood flow from the pulmocutaneous circulation to the heart before circulating through the rest of the body?