Deck 42: Circulation and Gas Exchange

Question 1

Which of the following would you expect of a species that has a high resting cardiac output?

A) The animal is likely small and compact, without the need to pump blood very far from the heart.
B) The species likely has very wide-diameter veins.
C) The animal likely has a very long distance between its heart and its brain.
D) The animal likely has a relatively inactive lifestyle.

Answer 1

C

Question 2

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

A) the capillaries have internal valves that slow the flow of blood
B) the diastolic blood pressure is too low to deliver blood to the capillaries at a high flow rate
C) the systemic capillaries are supplied by the left ventricle, which has a lower cardiac output than the right ventricle
D) 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 system

Answer 2

D

Question 3

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

Answer 3

C

Question 4

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) fishes
C) frogs
D) insects

Question 5

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

A) one capillary bed
B) two capillary beds
C) three capillary beds
D) four capillary beds

Question 6

Among the following choices, which organism likely has the highest systolic pressure?

A) mouse
B) human
C) hippopotamus
D) giraffe

Question 7

While jogging, a person has a stroke volume of 130 ml/beat and a heart rate of 120 beats per minute. If their resting stroke volume was 70 ml/beat and resting heart rate was 60 beats per minute, how did this person's cardiac output change?

A) Their cardiac output did not change. Only their respiratory rate changed.
B) During exercise, their cardiac output decreased by 11,400 ml/minute.
C) During exercise, their cardiac output increased by 60 ml/beat.
D) Their cardiac output increased from 4,200 ml/minute to 15,600 ml/minute after jogging.

Question 8

The circulatory systems of bony fishes, rays, and sharks are most similar to ________.

A) those of birds, with a four-chambered heart
B) the portal systems of mammals, where two capillary beds occur sequentially, without passage of blood through a pumping chamber
C) those of sponges, where gas exchange in all cells occurs directly with the external environment
D) those of humans, where there are four pumping chambers to drive blood flow

Question 9

An electrocardiogram (ECG)provides information about ________.

A) the pressure of blood in the heart chambers
B) the rhythm of heart contractions
C) the amount of oxygen in the blood as it leaves the heart
D) the speed of blood flow through the blood vessels

Question 10

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 systems involving only the nervous system
D) the need to cushion animals from trauma

Question 11

A patient with a heart rate of 70 beats per minute and a stroke volume of 70 mL/beat will have a cardiac output of ________.

A) 1,000 mL/minute
B) 1,400 mL/minute
C) 2,800 mL/minute
D) 4,900 mL/minute

Question 12

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

A) left ventricle → aorta → lungs → systemic circulation
B) vena cava → right atrium → right ventricle → pulmonary vein
C) pulmonary vein → left atrium → left ventricle → pulmonary circuit
D) vena cava → right atrium → right ventricle → pulmonary artery

Question 13

Atrial systole ________.

A) occurs at the same time as ventricular diastole
B) pumps blood to the aorta
C) refers to the relaxation of the cardiac muscle
D) only occurs in the left heart chambers

Question 14

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

A) the pulmonary vein and the superior vena cava
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

Question 15

Organisms with a circulating body 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
C) a gastrovascular cavity
D) branched tracheae

Question 16

An anthropologist discovers the fossilized heart of an extinct animal. The evidence indicates that the organism's heart was large, was well-formed, and had four chambers, with no connection between the right and left sides. A reasonable conclusion supported by these observations is that the ________.

A) animal had evolved from birds
B) animal was endothermic and had a high metabolic rate
C) animal was most closely related to alligators and crocodiles
D) species had little to no need to regulate blood pressure

Question 17

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) hemocoel
C) two-chambered heart
D) four-chambered heart

Question 18

In an open circulatory system, blood is ________.

A) always inside of vessels and is under higher pressure than in closed circulatory systems
B) not always confined to blood vessels and is under higher pressure than in closed circulatory systems
C) always inside of vessels and is under lower pressure than in closed circulatory systems
D) not always confined to blood vessels and is under lower pressure than in closed circulatory systems

Question 19

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) fishes
C) mammals
D) reptiles

Question 20

Damage to the sinoatrial node in humans would ________.

A) block conductance between the bundle branches and the Purkinje fibers
B) have a negative effect on peripheral resistance
C) disrupt the rate and timing of cardiac muscle contractions
D) have a direct effect on blood pressure monitors in the aorta

Question 21

Which of the following statements comparing respiration in fish and in mammals is correct?

A) The respiratory medium for fish carries more oxygen than the respiratory medium of mammals.
B) A countercurrent exchange mechanism between the respiratory medium and blood flow is seen in mammals but not in fish.
C) The movement of the respiratory medium in mammals is bidirectional, but in fish it is unidirectional.
D) In blood, oxygen is primarily transported by plasma in fish, but by red blood cells in mammals.

Question 22

Which of the following mechanisms are used to regulate blood pressure in the closed circulatory system of vertebrates?
I)changing the force of heart contraction
II)constricting and relaxing smooth muscle in the walls of arterioles
III)opening or closing precapillary sphincters

A) only I and II
B) only I and III
C) only II and III
D) I, II, and III

Question 23

You cut your finger, and after putting pressure on the wound for several minutes, you notice that it is still bleeding profusely. What may be the problem?

A) Platelets are not functioning properly, or there are too few to be effective.
B) Mast cells are not releasing their chemical messengers.
C) There are too many antigens to allow clotting.
D) Hemoglobin levels are too high to allow clotting.

Question 24

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

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 mm Hg systolic and/or greater than 90 mm Hg diastolic

Question 25

In order for blood to always flow unidirectionally through a closed circulatory system, the ________.

A) blood vessels farthest from the heart must have valves
B) capillaries must have a thick endothelium
C) arteries must be elastic
D) pressure in all vessels must be equal

Question 26

Although having evolved independently, the tracheal tubes of mammals and insects are both supported by rigid tissues. The trachea of a mammal is supported by cartilage, and the tracheae of an insect are supported by chitin. What selective pressure most likely led to the convergent evolution of these respiratory structures?

A) Both mammals and insects have similar oxygen needs.
B) When air is the respiratory medium, there is a greater risk that the tracheal tubes will collapse.
C) Insects and mammals both keep their internal temperature constant.
D) A decrease in environmental carbon dioxide made structural support necessary.

Question 27

If the osmotic pressure on the venous side of capillary beds is lower than the hydrostatic pressure, then ________.

A) hemoglobin will not release oxygen
B) fluid will tend to accumulate in tissues
C) the pH of the interstitial fluids will increase
D) plasma proteins will escape through the endothelium of the capillaries

Question 28

Small swollen areas in the neck, groin, and axillary region are associated with ________.

A) increased activity of the immune system
B) blood sugar that is abnormally high
C) dehydration
D) sodium depletion

Question 29

Humans infected with some types of parasitic worms develop a condition called elephantiasis, which is characterized by swelling of the limbs. Which of the following would be the most likely cause of elephantiasis?

A) The infected human's immune system is fighting the worms.
B) The worm infection is causing a decrease in cardiac output.
C) The worms are blocking the lymph vessels.
D) More blood is flowing through precapillary sphincters.

Question 30

When the air in a testing chamber is specially mixed so that its oxygen content is 10% and its overall air pressure is 400 mm Hg, then PO₂ is ________.

A) 400 mm Hg
B) 82 mm Hg
C) 40 mm Hg
D) 4 mm Hg

Question 31

Blood is pumped at high pressures in arteries from the heart to ensure that all parts of the body receive adequate blood flow. Capillary beds, however, would hemorrhage under direct arterial pressures. How does the design of the circulatory network contribute to reducing blood pressure to avoid this scenario?

A) Blood flow through the capillaries is essentially frictionless, and this reduces the amount of pressure on their walls.
B) The total cross-sectional diameter of the arterial circulation increases with progression from artery to arteriole to capillary, leading to a reduced blood pressure.
C) Fluid loss from the arteries is high enough that pressure drops off significantly by the time blood reaches the capillaries.
D) Capillary beds have the thickest walls of any blood vessel to resist these high pressures.

Question 32

Countercurrent exchange in the fish gill helps to maximize ________.

A) blood pressure
B) diffusion
C) active transport
D) osmosis

Question 33

To become bound to hemoglobin for transport in mammals, atmospheric molecules of oxygen must cross ________.

A) one membrane-that of the lining in the lungs-and then bind directly to hemoglobin, a protein dissolved in the plasma of the blood
B) two membranes-in and out of the cell lining the lung-and then bind directly to hemoglobin, a protein dissolved in the plasma of the blood
C) four membranes-in and out of the cell lining the lung, in and out of the endothelial cell lining an alveolar capillary-and then bind directly to hemoglobin, a protein dissolved in the plasma of the blood
D) five membranes-in and out of the cell lining the lung, in and out of the endothelial cell lining an alveolar capillary, and into the red blood cell-to bind with hemoglobin

Question 34

Cyanide poisons mitochondria by blocking the final step in the electron transport chain. Human red blood cells placed in an isotonic solution containing cyanide are likely to ________.

A) retain the normal cell shape, but the mitochondria will be poisoned
B) lyse as the cyanide concentration increases inside the cell
C) switch to anaerobic metabolism
D) be unaffected

Question 35

Large proteins such as albumin remain in capillaries rather than diffusing out, resulting in the ________.

A) loss of osmotic pressure in the capillaries
B) development of an osmotic pressure difference across capillary walls
C) loss of fluid from capillaries
D) increased diffusion of hemoglobin

Question 36

A normal event in the process of blood clotting is the ________.

A) production of erythropoietin
B) conversion of fibrin to fibrinogen
C) activation of prothrombin to thrombin
D) synthesis of hemoglobin

Question 37

________ is a hormone that is released from the ________ to stimulate the production of red blood cells.

A) Growth hormone; pancreas
B) Erythropoietin; kidney
C) Cortisol; adrenal gland
D) Acetylcholine; bone marrow

Question 38

Countercurrent exchange is evident in the flow of ________.

A) water across the gills of a fish and the blood within those gills
B) blood in the dorsal vessel of an insect and that of air within its tracheae
C) air within the primary bronchi of a human and the blood within the pulmonary veins
D) water across the skin of a frog and the blood flow within the ventricle of its heart

Question 39

Which of the following conditions would most likely be due to high blood pressure in a mammal?

A) bursting of blood vessels in capillary beds
B) inability of the right ventricle to contract
C) reversal of normal blood flow direction in arteries
D) destruction of red blood cells

Question 40

Blood cells that function to fight infection are called ________.

A) platelets
B) leukocytes
C) erythrocytes
D) thrombi

Question 41

What would be the consequence if we were to reverse the direction of water flow over the gills of a fish, moving water inward past the operculum, past the gills, then out the mouth? This reversal of water flow would ________.

A) reduce efficiency of gas exchange
B) change the exchange of gases in the body from carbon dioxide out and oxygen in to carbon dioxide in and oxygen out
C) increase the efficiency of gas exchange

Question 42

Carbon dioxide levels in the blood and cerebrospinal fluid affect pH. This enables the organism to sense a disturbance in gas levels as ________.

A) the brain directly measures and monitors oxygen levels and causes breathing changes accordingly
B) the medulla oblongata, which is in contact with cerebrospinal fluid, monitors pH and uses this measure to control breathing
C) the brain alters the pH of the cerebrospinal fluid to force the animal to retain more or less carbon dioxide
D) stretch receptors in the lungs cause the medulla oblongata to speed up or slow breathing

Question 43

A person with a tidal volume of 450 mL (milliliters), a vital capacity of 4000 mL, and a residual volume of 1000 mL would have a potential total lung capacity of ________.

A) 1450 mL
B) 4000 mL
C) 4450 mL
D) 5000 mL

Question 44

How has the avian lung adapted to the metabolic demands of flight?

A) Airflow through the avian lung is bidirectional like in mammals.
B) There is more dead space within the avian lung so that oxygen can be stored for future use.
C) Countercurrent circulation is present in the avian lung.
D) Gas exchange occurs during both inhalation and exhalation.

Question 45

Hyperventilation (rapid inhalation and exhalation)can result in respiratory alkalosis (increased blood pH). Why?

A) Hyperventilation results in inefficient gas exchange, and not enough oxygen is absorbed by the blood.
B) More metabolic waste is released into the blood, thus reducing the pH.
C) Rapid breathing depletes the blood of carbon dioxide, thus the blood pH increases.
D) Excess production of carbon dioxide decreases the affinity of hemoglobin for oxygen.

Question 46

An oil-water mixture works as an insecticidal spray against mosquitoes and other insects because it ________.

A) blocks the openings into the tracheal system
B) interferes with gas exchange across the capillaries
C) clogs their bronchi
D) prevents gases from leaving the atmosphere

Question 47

Which of the following events would you predict as carbon dioxide is released from your muscles into the surrounding capillary bed?

A) Oxygen delivery to muscle is increased when more carbon dioxide is produced by the muscle.
B) Because of the change in blood pH, the blood can carry more oxygen.
C) The amount of oxygen in venous blood will increase.
D) Arterial blood entering the capillaries will carry more oxygen.

Question 48

Under identical atmospheric conditions, freshwater ________.

A) has more dissolved oxygen than seawater
B) has less dissolved oxygen than seawater
C) can hold 10-40 times more carbon dioxide than air
D) can hold 10-40 times more oxygen than air

Question 49

Some human infants, especially those born prematurely, suffer serious respiratory failure because of ________.

A) the sudden change from the uterine environment to the air
B) the overproduction of surfactants
C) lung collapse due to inadequate production of surfactant
D) mutations in the genes involved in lung formation

Question 50

During aerobic exercise, the partial pressure of oxygen in muscle cells will ________, thus the rate of diffusion of oxygen into the muscle tissue from the blood will ________.

A) decrease; increase
B) increase; decrease
C) not change; also not change
D) decrease; decrease

Question 51

A decrease of blood pH from 7.4 to 7.2 causes hemoglobin to ________.

A) release all bound carbon dioxide molecules
B) bind more oxygen molecules
C) decrease its binding of H⁺
D) give up more of its oxygen molecules

Question 52

Which of the following represents the correct flow of air into the lung of a mammal?

A) trachea → bronchioles → bronchi → alveoli
B) larnyx → trachea → bronchi → bronchioles → alveoli
C) trachea → tracheoles → bronchi → alveoli
D) alveoli → tracheoles → bronchi → trachea

Question 53

During most daily activities, the human respiration rate is most closely linked to the blood levels of ________.

A) nitrogen
B) oxygen
C) carbon dioxide
D) carbon monoxide

Question 54

Atmospheric pressure at the summit of Mount Everest is about one third the pressure at sea level, which is 760 mm Hg. If oxygen makes up 21% of the atmosphere by volume, the partial pressure of oxygen (PO₂)on Mount Everest is approximately ________.

A) 53 mm Hg
B) 157 mm Hg
C) 255 mm Hg
D) 760 mm Hg

Question 55

Most of the carbon dioxide produced by humans is ________.

A) converted to bicarbonate ions
B) bound to hemoglobin
C) transported in the erythrocytes as carbonic acid
D) simply dissolved in the plasma

Question 56

Compared to mammals that are not adapted for diving, diving mammals ________.

A) have larger lungs
B) can store more oxygen in their muscles
C) use gills for gas exchange
D) always keep blood flowing to their lungs during a dive

Question 57

A rabbit taken from a meadow near sea level and moved to a meadow high on a mountainside would have some trouble breathing. Why?

A) The percentage of oxygen in the air at high elevations is lower than at sea level.
B) The percentage of oxygen in the air at high elevations is higher than at sea level.
C) The partial pressure of oxygen in the air at high elevations is lower than at sea level.
D) The partial pressure of oxygen in the air at high elevations is higher than at sea level.

Question 58

Based on the graph, which of the following statements is correct?

A) The greatest delivery of oxygen from the blood to the surrounding tissues occurs at 37C.
B) Increasing blood pH results in more oxygen unloading in tissues.
C) Colder blood temperature results in greater dissociation of oxygen and hemoglobin.
D) Hemoglobin has a lower affinity for oxygen under high temperature conditions.

Question 59

Consider the following reaction. If the pH of the blood was decreased, then the ________.
CO₂ + H₂O H₂CO₃ HCO₃⁻ + H⁺

A) amount of carbon dioxide would increase
B) bicarbonate in the blood would increase
C) amount of oxygen in the blood will decrease
D) amount of protons in the blood will increase

Question 60

The sun shining on a tidal pool during a hot day heats the water, causing some water to evaporate. Because the water has become warmer and saltier, ________.

A) the carbon dioxide content will increase
B) the oxygen content will decrease
C) it will be better able to sustain aerobic organisms
D) it will become more dense

Question 61

Blood returning to the mammalian heart in a pulmonary vein drains first into the

A) left atrium.
B) right atrium.
C) left ventricle.
D) right ventricle.

Question 62

Which of the following respiratory systems is not closely associated with a blood supply?

A) the lungs of a vertebrate
B) the gills of a fish
C) the tracheal system of an insect
D) the skin of an earthworm

Question 63

One feature that amphibians and humans have in common is

A) the number of heart chambers.
B) a complete separation of circuits for circulation.
C) the number of circuits for circulation.
D) a low blood pressure in the systemic circuit.

Question 64

When you hold your breath, which of the following blood gas changes first leads to the urge to breathe?

A) rising O₂
B) falling O₂
C) rising CO₂
D) falling CO₂

Question 65

Compared with the interstitial fluid that bathes active muscle cells, blood reaching these cells in arterioles has a

A) higher ᴾO₂.
B) higher ᴾCO₂.
C) greater bicarbonate concentration.
D) lower pH.

Question 66

Pulse is a direct measure of

A) blood pressure.
B) stroke volume.
C) cardiac output.
D) heart rate.

Question 67

If a molecule of CO₂ released into the blood in your left toe is exhaled from your nose, it must pass through all of the following except

A) the pulmonary vein.
B) the trachea.
C) the right atrium.
D) the right ventricle.