Deck 50: Circulatory Systems

Question 1

Which of the following structures is/are not part of the circulatory system of an earthworm?

A) Contractile vessels
B) A major dorsal vessel
C) Capillary beds in the lungs
D) Capillary beds in each segment
E) A major ventral vessel

Answer 1

C

Question 2

Autoregulation of blood flow to a tissue is due to

A) sympathetic innervation.
B) the release of ADH by the hypothalamus.
C) increased activity of baroreceptors.
D) chemoreceptors in the aorta and the carotid arteries.
E) the effect of the local chemical environment on arterioles.

Answer 2

E

Question 3

Which statement about the human heart is true?

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.

Answer 3

C

Question 4

Blood velocity through capillaries is slow because

A) much blood volume is lost from the capillaries.
B) the pressure in venules is high.
C) the total cross-sectional area of capillaries is larger than that of arterioles.
D) the osmotic pressure in capillaries is very high.
E) erythrocytes must pass through in single file.

Question 5

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

A) A pump is usually present.
B) Blood is pumped out of openings in the heart called ostia.
C) The blood is the interstitial fluid.
D) Tissue fluid bathes the tissues directly.
E) Many mollusks and all arthropods have open circulatory systems.

Question 6

How are lymphatic vessels like veins?

A) Both have nodes where they join together into larger common vessels.
B) Both carry blood under low pressure.
C) Both are capacitance vessels.
D) Both have valves.
E) Both carry fluids rich in plasma proteins.

Question 7

A cardiovascular system is not necessary in the hydra because the hydra

A) is an aquatic animal.
B) has no skeleton.
C) is only two cells thick.
D) has tentacles to move water.
E) does not move rapidly.

Question 8

Which of the following statements about gastrovascular cavities is false?

A) Organisms with gastrovascular cavities tend to be only a few cells thick.
B) Gastrovascular cavities are always highly branched.
C) Gastrovascular cavities are filled with interstitial fluid.
D) The diffusion path length in organisms with gastrovascular cavities is usually short.
E) Large organisms do not usually have gastrovascular cavities.

Question 9

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

A) Bat
B) Earthworm
C) Hydra
D) Snail
E) Lizard

Question 10

In animals with a closed circulatory system, the liquid around the body cells is called

A) blood plasma.
B) interstitial fluid.
C) mesolymph.
D) hemolymph.
E) aguavida.

Question 11

Which of the following is an advantage of closed circulatory systems as compared to open circulatory systems?

A) Transport occurs more rapidly.
B) Closed systems can direct blood to specific tissues.
C) In closed systems, cells and large molecules can be kept separate from the animal's intercellular material.
D) Closed systems can support higher levels of metabolic activity.
E) All of the above

Question 12

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

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 above

Question 13

The pacemaker action potentials in the heart

A) are due to opposing actions of norepinephrine and acetylcholine.
B) are generated by the bundle of His.
C) depend on the gap junctions between the cells that make up the atria and those that make up the ventricles.
D) are due to spontaneous depolarization of the plasma membranes of modified cardiac muscle cells.
E) result from hyperpolarization of cells in the sinoatrial node.

Question 14

Which of the following is not transported through a closed circulatory system?

A) Heat
B) Respiratory gases
C) Gametes
D) Hormones
E) All of the above are transported through closed circulatory systems.

Question 15

An open circulatory system is characterized by

A) the absence of a heart.
B) the absence of blood vessels.
C) blood with a composition different from that of tissue fluid.
D) the absence of capillaries.
E) a higher-pressure circuit through gills than to other organs.

Question 16

Which of the following does not increase blood flow through a capillary bed?

A) High concentration of CO₂
B) High concentration of lactate and hydrogen ions
C) Histamine
D) ADH
E) Increase in arterial pressure

Question 17

Which statement about vertebrate circulatory systems is not true?

A) In fish, oxygenated blood from the gills returns to the heart through the left atrium.
B) In mammals, deoxygenated blood leaves the heart through the pulmonary artery.
C) In amphibians, deoxygenated blood enters the heart through the right atrium.
D) In reptiles, the blood in the pulmonary artery has a lower oxygen content than the blood in the aorta.
E) In birds, the pressure in the aorta is higher than the pressure in the pulmonary artery.

Question 18

The production of erythrocytes

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.

Question 19

Blood clotting

A) is impaired in patients with hemophilia because they do not produce platelets.
B) is initiated when platelets release fibrinogen.
C) involves a cascade of factors produced in the liver.
D) is initiated by leukocytes forming a meshwork.
E) requires production of angiotensin.

Question 20

In an open circulatory system,

A) there is no heart.
B) there is a gastrovascular cavity.
C) there are no blood vessels.
D) blood flows out of the body.
E) there is no distinction between blood and tissue fluid.

Question 21

The benefit provided by a heart with two atria is

A) the separation of oxygenated and deoxygenated blood.
B) that blood moving to the body tissues is at a higher pressure than it would be if it had flowed through the lungs first.
C) that blood moving to the lungs is at a higher pressure than it would be if it had flowed through the body first.
D) that blood moving to the body tissues is at a lower pressure than it would be if it had flowed through the lungs first.
E) that there are two muscular regions for pumping.

Question 22

When submerged, frogs receive most of their O₂ from capillaries within the skin. Which of the following structures would contain blood with the highest O₂ concentration in a submerged frog that is not able to breathe using its lungs?

A) Right atrium
B) Left atrium
C) Aorta
D) Ventricle
E) Pulmonary vein

Question 23

In a vertebrate with a four-chambered heart, the structure or region containing blood with the lowest O₂ concentration is the

A) pulmonary vein.
B) pulmonary artery.
C) left atrium.
D) aorta.
E) arteriole end of a capillary.

Question 24

In the cardiac cycle, blood pressure is at its maximum when the _______ are _______ during _______.

A) atria; contracting; systole
B) atria; contracting; diastole
C) ventricles; contracting; systole
D) ventricles; relaxing; systole
E) ventricles; relaxing; diastole

Question 25

Which of the following vertebrates has a three-chambered heart with both pulmonary and systemic circuits?

A) Fish
B) Lungfish
C) Amphibians
D) Crocodilians
E) Both b and c

Question 26

Imagine that a paleontologist finds a fragment of a fossilized vertebrate that indicates that the animal had a four-chambered heart. The animal could be a(n)

A) fish.
B) amphibian.
C) crocodile.
D) bird.
E) Both c and d

Question 27

The left ventricle in humans is more muscular than the right ventricle because

A) resistance is higher in the systemic circuit.
B) resistance is higher in the pulmonary circuit.
C) it pumps more total blood.
D) it pumps more viscous blood.
E) None of the above

Question 28

In humans, oxygenated blood is transported from the lung to the heart by the

A) pulmonary artery.
B) pulmonary vein.
C) superior vena cava.
D) inferior vena cava.
E) coronary artery.

Question 29

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

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.

Question 30

How can arthropods maintain a high metabolism despite the absence of a closed circulatory system?

A) In species with wings, the beating of the wings moves air across their tissues, thus acting analogously to a heart pumping blood through vessels.
B) They do not use their circulatory system for gas exchange.
C) They have small tubes throughout their bodies bring air from the outside to the tissues.
D) Both b and c
E) None of the above

Question 31

In the human heart, blood is pumped from the left ventricle into the

A) right ventricle.
B) left atrium.
C) right atrium.
D) pulmonary circuit.
E) systemic circuit.

Question 32

Which of the following groups of vertebrates is phylogenetically oldest and retains the ancestral type of heart?

A) Reptiles
B) Amphibians
C) Fishes
D) Birds
E) Mammals

Question 33

In the fish circulatory system, blood

A) moves from the muscular ventricle to the gills.
B) entering the aorta is under high pressure.
C) leaving the heart moves to body tissues.
D) leaving the gills is under high pressure.
E) is received from the body into a muscular atrium.

Question 34

Suppose a paleontologist finds a fragment of a fossilized vertebrate that indicates that the animal had a three-chambered heart. The animal could be a(n)

A) tuna.
B) salamander.
C) crocodile.
D) eagle.
E) Both b and c

Question 35

Which of the following is not an advantage of closed circulatory systems as compared to open systems?

A) Closed systems move wastes and nutrients more quickly.
B) Molecules specialized as carriers of hormones and nutrients can be stored in closed systems when not in use.
C) As certain tissues experience a greater need for respiratory gases, closed systems can prioritize the delivery of gases to them.
D) In hermaphroditic species, closed systems can deliver gametes from one set of sex organs directly to the other.
E) As certain tissues experience a greater need for nutrients, closed systems can prioritize the delivery of nutrients to them.

Question 36

Oxygenated blood is carried by the

A) aorta.
B) pulmonary vein.
C) pulmonary artery.
D) Both a and b
E) Both a and c

Question 37

In vertebrates, exchange of substances between the blood and the interstitial fluids occurs in the

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

Question 38

In the evolution of the vertebrate circulatory system, a transitional step led to separate pulmonary and systemic circuits. This step can be observed in

A) lungfish.
B) the ancient ostracoderm.
C) birds.
D) amphibians.
E) reptiles.

Question 39

Crocodilians differ from other reptiles in that they have

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

Question 40

In humans, which vessel empties into the right atrium?

A) Pulmonary vein
B) Inferior vena cava
C) Superior vena cava
D) Pulmonary artery
E) Both b and c

Question 41

"Systole" and "diastole" describe the _______ and _______, respectively, of the _______ in mammals.

A) relaxation; contraction; ventricles
B) contraction; relaxation; ventricles
C) relaxation; contraction; atria
D) contraction; relaxation; atria
E) None of the above

Question 42

Which of the following statements about blood cells is false?

A) There are at least 500 times as many red as white blood cells.
B) Erythrocytes are anucleate in mammals.
C) The biconcave shape of the erythrocyte creates a large surface area for gas exchange.
D) Red blood cells are generated by stem cells in the spleen.
E) Leukocytes destroy foreign cells.

Question 43

Which of the following concerning the heartbeat is true?

A) Only the ventricles contract in unison.
B) Only the atria contract in unison.
C) The atria contract together in unison, and the ventricles contract in unison.
D) Only the atrium and ventricle on the right side of the heart contract in unison.
E) Only the atrium and ventricle on the left side of the heart contract in unison.

Question 44

When whole blood is centrifuged, it is separated into a liquid component called _______ and a bottom layer of _______.

A) hematocrit; cells
B) plasma; cells
C) plaque; cells
D) hematocrit; plasma
E) packed cell volume; plasma

Question 45

Heart murmurs result from defective

A) heart muscle.
B) arterioles.
C) ventricular contraction.
D) blood supply to the heart.
E) heart valves.

Question 46

In normal humans the hematocrit, or percentage of the blood made up of cells, is about _______ percent.

A) 10
B) 25
C) 40
D) 70
E) 90

Question 47

The timing of the spread of the action potential from atrium to ventricle is controlled by the

A) sinoatrial node.
B) atrioventricular node.
C) Purkinje fibers.
D) bundle of His.
E) ventricular mass.

Question 48

The most abundant cells in the blood are

A) erythrocytes.
B) leukocytes.
C) phagocytes.
D) platelets.
E) None of the above

Question 49

Gap junctions

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.

Question 50

The function of leukocytes is to

A) destroy foreign cells or to produce antibodies.
B) transport respiratory gases.
C) stimulate blood clotting.
D) distribute nutrients to tissues.
E) produce the different types of blood cells.

Question 51

The hormone erythropoietin is released by the kidney

A) to remove old red blood cells from circulation.
B) in response to high levels of oxygen in circulation.
C) in response to low levels of hemoglobin.
D) to stimulate production of red blood cells.
E) to stimulate platelet formation.

Question 52

A blood pressure represented as 140/100 means that the

A) pressure during ventricular contraction is 140, while the pressure during ventricular relaxation is 100.
B) pressure during ventricular contraction is 100, while the pressure during ventricular relaxation is 140.
C) pressure during ventricular contraction is 140, while the pressure during atrial contraction is 100.
D) pressure during atrial contraction is 140, while the pressure during ventricular contraction is 100.
E) diastolic pressure is 140 and the systolic pressure is 100.

Question 53

A platelet is activated to initiate clotting

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.

Question 54

In the electrocardiogram (EKG) of a normal cardiac cycle, the wave called T corresponds to

A) depolarization of the atria.
B) depolarization of the ventricles.
C) repolarization of the atria.
D) repolarization of the ventricles.
E) Both a and b

Question 55

The circulating protein fibrinogen contributes to blood clotting by

A) polymerizing to form fibrin threads.
B) acting as a catalyst for thrombin activation.
C) binding to red blood cells.
D) activating the platelets.
E) triggering phagocytosis by the leukocytes.

Question 56

Which of the following heart regions is third in sequence of action potential propagation during a normal heartbeat?

A) Bundle of His
B) Atrioventricular node
C) Purkinje fibers
D) Sinoatrial node
E) Ventricular muscle cells

Question 57

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

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 above

Question 58

The specific location of the heart pacemaker is the

A) sinoatrial node.
B) atrioventricular node.
C) Purkinje fibers.
D) bundle of His.
E) ventricular mass.

Question 59

The mature red blood cells of humans

A) are more than 75 percent hemoglobin.
B) contain no nuclei or endoplasmic reticulum.
C) have a nearly spherical shape.
D) have a relatively low surface area-to-volume ratio.
E) have a rigid shape and low flexibility.

Question 60

The heart beats because of cardiac muscle's unique properties, such as

A) high resistance to outside stimulation.
B) cell communication via gap junctions.
C) a low level of electrical activity.
D) an external pacemaking system.
E) rapid chemical communication.

Question 61

Blockage of a coronary artery can cause

A) a heart attack.
B) stroke.
C) fainting.
D) edema.
E) anemia.

Question 62

The blood vessels with the greatest capacity to store blood are the

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

Question 63

Blood is at its lowest pressure in the

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

Question 64

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

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

Question 65

Which of the following circulatory components is not normally found circulating in the plasma?

A) Platelets
B) Thrombin
C) Albumin
D) Fibrinogen
E) Both a and c

Question 66

Which of the following is not a mechanism that facilitates return of venous blood to the heart?

A) Gravity, when veins are above the heart
B) Contraction of skeletal muscles
C) Breathing
D) Contraction of smooth muscle in most veins of the body
E) Valves in veins

Question 67

A high _______ will lead to an autoregulatory increase of blood flow to a tissue.

A) blood pressure
B) CO₂ concentration
C) O₂ concentration
D) ATP concentration
E) glucose concentration

Question 68

Lymph nodes are sites

A) where bacteria can grow.
B) where inflammation occurs.
C) that regulate blood fluid.
D) where new cells enter.
E) of mechanical filtering.

Question 69

The lifetime of an individual red blood cell is approximately

A) 4 hours.
B) 4 days.
C) 4 weeks.
D) 40 days.
E) 4 months.

Question 70

Which of the following statements about the lymphatic system is false?

A) The lymphatic system conducts lymph from the lymph capillaries to the thoracic duct, where it enters the circulatory system.
B) Lymph is identical to blood except that it does not contain erythrocytes.
C) Lymphoid capillaries are distributed throughout the body.
D) Contraction of skeletal muscles propels the lymph.
E) Lymph nodes are an important part of the defense system that combats infections.

Question 71

The diameter of a capillary is about the same as that of a(n)

A) arteriole.
B) nerve.
C) red blood cell.
D) valve.
E) venule.

Question 72

Histamine causes inflammation by

A) making blood vessels expand and decreasing the permeability of capillaries.
B) making blood vessels contract and decreasing the permeability of capillaries.
C) making blood vessels expand and increasing the pressure in capillaries.
D) decreasing the permeability of and increasing the pressure in capillaries.
E) increasing the permeability of and the pressure in capillaries.

Question 73

Which of the following is not a risk factor for developing atherosclerosis?

A) A high-fat and high-cholesterol diet
B) Smoking
C) High altitude
D) Inactive lifestyle
E) Hypertension

Question 74

Which of the following statements about veins is true?

A) The veins may hold as much as 60 percent of total blood volume at any one time.
B) Veins are capacitance vessels.
C) The walls of veins are more expandable than the walls of arteries.
D) Veins are resistance vessels.
E) a, b, and c

Question 75

The movement of blood in the veins toward the heart is caused by

A) gravity.
B) the contraction of venous walls.
C) cilia lining the veins.
D) the contraction of nearby muscles.
E) venous capacitance.

Question 76

Blood pressure is _______ than osmotic pressure at the arterial end of a capillary bed, which is where the process of _______ occurs.

A) greater; reabsorption
B) greater; filtration
C) lesser; reabsorption
D) lesser; filtration
E) lesser; edema

Question 77

When a piece of thrombus breaks loose and lodges in a smaller vessel, blocking the flow of blood, the result is

A) thrombosis.
B) an infarction.
C) an embolism.
D) atherosclerosis.
E) a hematocrit.

Question 78

As blood enters the capillaries from the arterioles, blood pressure _______ and osmotic potential _______.

A) decreases; decreases
B) decreases; increases
C) increases; decreases
D) decreases; remains steady
E) increases; remains steady

Question 79

Which of the following statements about valves is false?

A) Defective heart valves produce sounds called heart murmurs.
B) Veins and lymphatic vessels have two-way valves.
C) Varicose veins result when valves within veins can no longer prevent backflow of blood.
D) The pulmonary valve is located between the right ventricle and the pulmonary artery.
E) Atrioventricular valves prevent backflow of blood into the atria when the ventricles contract.

Question 80

The Frank-Starling law suggests that during exercise, the

A) flow of blood through the heart speeds up.
B) heart is stretched and contracts more forcefully.
C) veins expand to handle increased blood flow.
D) heart fills to capacity with blood at each beat.
E) valves in veins can no longer prevent backflow.