Deck 42: Circulation and Gas Exchange

Question 1

A patient has a blood pressure of 120/75, a pulse rate of 40 beats/min, a stroke volume of 70 mL/beat, and a respiratory rate of 25 breaths/min. This person's cardiac output per minute will be

A)500 mL.
B)1,000 mL.
C)1,750 mL.
D)2,800 mL.
E)4,800 mL.

Answer 1

D

Question 2

Which of the following is measured by an electrocardiogram?

A)impulses from the AV node
B)impulses of the parasympathetic nervous system that control heart beat
C)the spread of impulses from the SA node
D)contraction of the two atria
E)systole and diastole

Answer 2

C

Question 3

What would be expected if the amount of interstitial fluid surrounding the capillary beds of the lungs were to increase significantly?

A)The amount of carbon dioxide entering the lungs from the blood would increase.
B)The amount of oxygen entering the circulation from the lungs would increase.
C)The amount of oxygen entering the circulation from the lungs would decrease.
D)The pressure would cause the capillary beds to burst.
E)Both C and D would be expected.

Answer 3

C

Question 4

Organisms in which a circulating body fluid is distinct from the fluid that directly surrounds the body's cells are likely to have which of the following?

A)an open circulatory system
B)a closed circulatory system
C)a gastrovascular cavity
D)branched tracheae
E)hemolymph

Question 5

Which of the following would be described as a portal system?

A)an area connecting arterioles to venules
B)a series of vessels that returns blood to the heart in an animal with an open circulatory system
C)a space within or between organs where blood is allowed to pool
D)a slightly muscular vessel that has minimal pumping action in an organism with no heart
E)a vessel or vessels connecting two capillary beds

Question 6

Average blood pressure is lowest in which structure(s)?

A)the aorta
B)arteries
C)arterioles
D)capillaries
E)venae cavae

Question 7

Why is the velocity of blood flow the lowest in capillaries?

A)The capillary walls are not thin enough to allow oxygen to exchange with the cells.
B)Capillaries are far from the heart, and blood flow slows as distance from the heart increases.
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 surface area of the capillaries is larger than the total surface area of the arterioles.

Question 8

The average resting stroke volume of the heart is 70 mL and it beats ~72 times per minute. This would result in which cardiac output?

A)5 L/minute
B)504 mL/minute
C)0)5 L/minute
D)50 L/minute
E)500 L/minute

Question 9

If the atrioventricular node could be surgically removed from the heart without disrupting signal transmission to the Purkinje fibers, what would be the effect?

A)No apparent effect on heart activity would be observed.
B)The heart rate would be decreased.
C)Only the ventricles would contract.
D)Only the atria would contract.
E)Atria and ventricles would contract at about the same time.

Question 10

A nonfunctional sinoatrial node would

A)have no adverse effects on heart contraction.
B)cause the heart to stop beating in an autorhythmic fashion.
C)result in a block in ventricular contractions.
D)cause no effects because hormones will take over regulation of the heartbeat.
E)have little significant effect on stroke volume.

Question 11

Which sequence of blood flow can be observed in either a reptile or a mammal?

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

Question 12

Which of the following are the only vertebrates in which blood flows directly from respiratory organs to body tissues without first returning to the heart?

A)amphibians
B)birds
C)fishes
D)mammals
E)reptiles

Question 13

Which of the following is correct for a blood pressure reading of 130/80?
I) The systolic pressure is 130.
II) The diastolic pressure is 80.
III) The blood pressure during heart contraction is 80.

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

Question 14

An anthropologist discovers fossilized animal remains that give strong evidence that the organism had a large, well-formed, most likely 4-chambered heart, with no connection between the right and left sides. Which of the following could most reasonably be hypothesized from this observation?

A)that the animal and its relatives had evolved from birds
B)that the animal had a high energy requirement and was endothermic
C)that the animal was most closely related to reptiles such as alligators and crocodiles
D)that the animal was a kind of invertebrate
E)that the species had little to no need to regulate blood pressure

Question 15

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. From this point in the artery, how many capillary beds must this red blood cell pass through before it returns to the left ventricle of the heart?

A)one
B)two
C)three
D)four
E)five

Question 16

Diffusion rate is proportional to the square of the distance molecules/ions travel. Which of the following would therefore be preferable for a mid-size multicellular organism?

A)direct exchange of nutrients with the surrounding medium
B)a system for bringing nutrients into contact with cells, and another system for bringing to cells $\mathrm { O } _ { 2 }$
C)a system to circulate gases, nutrients, and wastes to and from cells
D)a system for facilitated diffusion to maximize materials that could be exchanged
E)a system of individualized exchange tubules for each cell group

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)lymphatic system.
D)two-chambered heart.
E)four-chambered heart.

Question 18

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

A)annelid
B)mollusc
C)fish
D)frog
E)insect

Question 19

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 have a negative effect on peripheral resistance.
D)would disrupt the rate and timing of cardiac muscle contractions.
E)would have a direct effect on blood pressure monitors in the aorta.

Question 20

Where are semilunar valves to be found in the mammalian heart?

A)where blood goes from atria to ventricles
B)on the right side of the heart only
C)where the pulmonary veins attach to the heart
D)at the places where blood leaves via the aorta and pulmonary arteries
E)at the places where the anterior and posterior venae cavae enter

Question 21

Which of the following features do all gas exchange systems have in common?

A)The exchange surfaces are moist.
B)They are enclosed within ribs.
C)They are maintained at a constant temperature.
D)They are exposed to air.
E)They are found only in animals.

Question 22

Dialysis patients, who will have blood withdrawn, dialyzed, then replaced, are always weighed when they enter the facility and then weighed carefully again before they leave. What is the most likely explanation for this requirement?

A)Even small changes in body weight may signify changes in blood volume and therefore blood pressure.
B)Many people who have dialysis are diabetic and must control their weight carefully.
C)Dialysis removes blood proteins and these weigh more than other blood components.
D)Dialysis is likely to cause edema and such swelling must be controlled.
E)Reclining posture during dialysis can cause a tendency for weight gain.

Question 23

Which of these are involved in the early stages of blood clotting?

A)low-density lipoproteins
B)immunoglobulins
C)erythropoietin
D)epinephrine
E)platelets

Question 24

Which of these stimulate the production of red blood cells?

A)low-density lipoproteins
B)immunoglobulins
C)erythropoietin
D)epinephrine
E)platelets

Question 25

The meshwork that forms the fabric of a blood clot consists mostly of which protein?

A)fibrinogen
B)fibrin
C)thrombin
D)prothrombin
E)collagen

Question 26

A blood vessel has the following characteristics: outer layer of connective tissue, a thick layer of smooth muscle with elastic fibers, no valves. It is which of the following?

A)a vein
B)a venule
C)an artery
D)a capillary
E)a portal vessel

Question 27

What would be the long-term effect if the lymphatic vessels associated with a capillary bed were to become blocked?

A)More fluid would enter the venous capillaries.
B)Blood pressure in the capillary bed would increase.
C)Fluid would accumulate in interstitial areas.
D)Fewer proteins would leak into the interstitial fluid from the blood.
E)Nothing would happen.

Question 28

What is the reason that fluid is forced from the bloodstream to the surrounding tissues at the arteriole end of systemic capillaries?

A)The osmotic pressure of the interstitial fluid is greater than that of the blood.
B)The hydrostatic pressure of the blood is less than that of the interstitial fluid.
C)The hydrostatic pressure of the blood is greater than the osmotic pressure of the blood.
D)The osmotic pressure of the interstitial fluid is greater than the hydrostatic pressure of the blood.
E)The osmotic pressure of the blood is greater than the hydrostatic pressure of the interstitial fluid.

Question 29

Which of these speed up heart rate?

A)low-density lipoproteins
B)immunoglobulins
C)erythropoietin
D)epinephrine
E)platelets

Question 30

Which of the following is used to diagnose hypertension in adults?

A)measurement of fatty deposits on the endothelium of arteries
B)measurement of the LDL/HDL ratio in peripheral blood
C)percent of blood volume made up of platelets
D)blood pressure of >140 mm Hg systolic and/or >90 diastolic
E)number of leukocytes per mm3 of blood

Question 31

Cyanide acts as a mitochondrial poison by blocking the final step in the electron transport chain. What will happen to human red blood cells if they are placed in an isotonic solution containing cyanide?

A)The cell shape will be maintained, but the mitochondria will be poisoned.
B)The cells will lyse as the cyanide concentration increases inside the cell.
C)As a protective mechanism, the cells will switch to anaerobic metabolism.
D)The cells will not be able to carry oxygen.
E)The cells will probably be unaffected.

Question 32

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

A)hemoglobin will not release oxygen.
B)fluids will tend to accumulate in tissues.
C)the pH of the interstitial fluids 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 capillaries.

Question 33

Which of the following is predicted in someone who smokes and whose diet includes significant trans fats?

A)increased HDL levels
B)decreased LDL levels
C)increased blood vessel inflammation
D)reduced deposition of cholesterol in blood vessels
E)decreased amounts of C-reactive protein secreted by the liver

Question 34

A species has a normal resting systolic blood pressure of >260 mm Hg. What is the most probable hypothesis?

A)The animal is small and does not need the blood pumped far.
B)The animal is obese.
C)The species has very wide diameter veins.
D)The animal has a very long distance between heart and brain.
E)The species is characterized by frequent, quick motions.

Question 35

Which of the following is a normal event in the process of blood clotting?

A)production of erythropoietin
B)conversion of fibrin to fibrinogen
C)activation of prothrombin to thrombin
D)increase in platelets
E)clotting factor formation

Question 36

Which of the following is/are a cause(s)of vasoconstriction?

A)lying down after standing
B)standing after lying down
C)stress or hormone concentration
D)increased blood pressure
E)histamine secretion

Question 37

Human plasma proteins include which of the following?
I) fibrinogen
II) hemoglobin
III) immunoglobulin

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

Question 38

Large proteins such as albumin remain in capillaries rather than diffusing out. Which of the following does this cause?

A)loss of osmotic pressure in the capillaries
B)creation of an osmotic pressure difference across capillary walls
C)loss of fluid from capillaries
D)increased diffusion of CO2
E)increased diffusion of Hb

Question 39

Why is gas exchange more difficult for aquatic animals with gills than for terrestrial animals with lungs?

A)Water is less dense than air.
B)Water contains much less O2 than air per unit volume.
C)Gills have less surface area than lungs.
D)Gills allow only unidirectional transport
E)Gills allow water to flow in one direction

Question 40

Which of the following is a function of plasma proteins in humans?

A)maintenance of blood osmotic pressure
B)transport of water-soluble lipids
C)gas exchange
D)aerobic metabolism
E)oxygen transport

Question 41

Which of the following occurs with the exhalation of air from human lungs?

A)The volume of the thoracic cavity decreases.
B)The residual volume of the lungs decreases.
C)The diaphragm contracts.
D)The epiglottis closes.
E)The rib cage expands.

Question 42

Countercurrent exchange in the fish gill helps to maximize which of the following?

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

Question 43

Use the following information to answer the next questions.
Atmospheric pressure at sea level is equal to a column of 760 mm Hg.
Oxygen makes up 21% of the atmosphere by volume.
What is the partial pressure of oxygen (PO2)?

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

Question 44

Which of the following lung volumes would be different in a person at rest compared with when the person exercises?

A)tidal volume
B)vital capacity
C)residual volume
D)total lung capacity
E)All of the above would be different.

Question 45

A person with a tidal volume of 450 mL, a vital capacity of 4,000 mL, and a residual volume of 1,000 mL would have a potential total lung capacity of

A)1,450 mL.
B)4,000 mL.
C)4,450 mL.
D)5,000 mL.
E)5,450 mL.

Question 46

A group of students was designing an experiment to test the effect of smoking on grass frogs. They hypothesized that to keep the frogs in a smoke-filled environment for defined periods would result in lung cancer in the animals. However, when they searched for previously published information to shore up their hypothesis, they discovered they were quite wrong in their original assessment. Even though they were never going to go ahead with their experiment (so as not to harm frogs needlessly)they knew that a more likely outcome would be which of the following?

A)the amphibian equivalent of hypertension
B)skin cancer
C)gill abnormalities in the next generation of tadpoles
D)tracheal tube abnormalities
E)diminished absorption of oxygen

Question 47

The blood level of which gas is most important in controlling human respiration rate?

A)nitric acid
B)nitrogen
C)oxygen
D)carbon dioxide
E)carbon monoxide

Question 48

Air rushes into the lungs of humans during inhalation because

A)the rib muscles and diaphragm contract, increasing the lung volume.
B)pressure in the alveoli increases.
C)gas flows from a region of lower pressure to a region of higher pressure.
D)pulmonary muscles contract and pull on the outer surface of the lungs.
E)a positive respiratory pressure is created when the diaphragm relaxes.

Question 49

The following questions refer to the data shown below.
Blood entering a capillary bed of a vertebrate was measured for the pressures exerted by various factors.
$$\begin{array} { l c c } & \begin{array} { c } \text { Arterial End of } \\\text { Capillary Bed }\end{array} & \begin{array} { c } \text { Venous End of } \\\text { Capillary Bed }\end{array} \\\hline \text { Hydrostatic pressure } & 10 \mathrm {~mm} \mathrm { Hg } & 14 \mathrm {~mm} \mathrm { Hg } \\\text { Osmotic pressure } & 26 \mathrm {~mm} \mathrm { Hg } & 26 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PO } _ { 2 } & 100 \mathrm {~mm} \mathrm { Hg } & 42 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PCO } _ { 2 } & 40 \mathrm {~mm} \mathrm { Hg } & 46 \mathrm {~mm} \mathrm { Hg }\end{array}$$
Figure 42.1

-For this capillary bed, which of the following statements is correct?

A)The pH is lower on the arterial side than on the venous side.
B)Oxygen is taken up by the erythrocytes within the capillaries.
C)The osmotic pressure remains constant due to carbon dioxide compensation.
D)The hydrostatic pressure declines from the arterial side to the venous side because oxygen is lost.
E)Fluids will leave the capillaries on the arterial side of the bed and re-enter on the venous side.

Question 50

At an atmospheric pressure of 870 mm Hg, what is the contribution of oxygen?

A)100 mm Hg
B)127 mm Hg
C)151 mm Hg
D)182 mm Hg
E)219 mm Hg

Question 51

Where do air-breathing insects carry out gas exchange?

A)in specialized external gills
B)in specialized internal gills
C)in the alveoli of their lungs
D)across the membranes of cells
E)across the thin cuticular exoskeleton

Question 52

Why is the respiratory system of a bird more efficient than the human respiratory system?

A)The bird respiratory system does not mix exhaled air with inhaled air.
B)A bird lung contains multiple alveoli, which increases the amount of surface area available for gas exchange.
C)The human respiratory system ends in small parabronchi, which reduce the amount of surface area available for gas exchange.
D)Only B and C are correct.
E)A, B, and C are correct.

Question 53

An oil-water mixture is used as a spray against mosquitoes. How might this spray also affect gas exchange in other insects?

A)The oil might coat their lungs.
B)The oil might block the openings into the tracheal system.
C)The oil might interfere with gas exchange across the capillaries.
D)Only A and B are correct.
E)A, B, and C are correct.

Question 54

Some human infants, especially those born prematurely, suffer serious respiratory failure. This most probably relates to which of the following?

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

Question 55

Breathing is usually regulated by

A)erythropoietin levels in the blood.
B)the concentration of red blood cells.
C)hemoglobin levels in the blood.
D)CO2 and O2 concentration and pH-level sensors.
E)the lungs and the larynx.

Question 56

Which of the following is an example of countercurrent exchange?

A)the flow of water across the gills of a fish and that of blood within those gills
B)the flow of blood in the dorsal vessel of an insect and that of air within its tracheae
C)the flow of air within the primary bronchi of a human and that of blood within the pulmonary veins
D)the flow of water across the skin of a frog and that of blood within the ventricle of its heart
E)the flow of fluid out of the arterial end of a capillary and that of fluid back into the venous end of the same capillary

Question 57

Use the following information to answer the next questions.
Atmospheric pressure at sea level is equal to a column of 760 mm Hg.
Oxygen makes up 21% of the atmosphere by volume.
If the partial pressure of CO2 at sea level is approximately 0.23 mm Hg, how does this influence gas exchange in terrestrial animals?

A)the higher pressure of oxygen causes the lung surface to extract oxygen and give up carbon dioxide
B)the lower pressure of oxygen causes the lung surface to extract oxygen and give up carbon dioxide
C)the low concentration of carbon dioxide causes the oxygen to move across the lung surface
D)the low concentration of carbon dioxide causes the carbon dioxide to exert pressure on the inner lung surface
E)since the concentration of oxygen is lower in water, the moist surface of the lung extracts less carbon dioxide

Question 58

At the summit of a high mountain, the atmospheric pressure is 380 mm Hg. If the atmosphere is still composed of 21% oxygen, what is the partial pressure of oxygen at this altitude?

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

Question 59

Tidal volume in respiration is analogous to what measurement in cardiac physiology?

A)cardiac output
B)heart rate
C)stroke volume
D)systolic pressure
E)diastolic pressure

Question 60

At sea level, atmospheric pressure is 760 mm Hg. Oxygen gas is approximately 21% of the total gases in the atmosphere. What is the approximate partial pressure of oxygen?

A)0)2 mm Hg
B)20.0 mm Hg
C)76.0 mm Hg
D)160.0 mm Hg
E)508.0 mm Hg

Question 61

Draw a pair of simple diagrams comparing the essential features of single and double circulation.

Question 62

The following questions refer to the data shown below.
Blood entering a capillary bed of a vertebrate was measured for the pressures exerted by various factors.
$$\begin{array} { l c c } & \begin{array} { c } \text { Arterial End of } \\\text { Capillary Bed }\end{array} & \begin{array} { c } \text { Venous End of } \\\text { Capillary Bed }\end{array} \\\hline \text { Hydrostatic pressure } & 10 \mathrm {~mm} \mathrm { Hg } & 14 \mathrm {~mm} \mathrm { Hg } \\\text { Osmotic pressure } & 26 \mathrm {~mm} \mathrm { Hg } & 26 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PO } _ { 2 } & 100 \mathrm {~mm} \mathrm { Hg } & 42 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PCO } _ { 2 } & 40 \mathrm {~mm} \mathrm { Hg } & 46 \mathrm {~mm} \mathrm { Hg }\end{array}$$
Figure 42.1

-Blood carbon dioxide levels determine the pH of other body fluids as well as blood, including the pH of cerebrospinal fluid. How does this enable the organism to control breathing?

A)The brain directly measures and monitors carbon dioxide and causes breathing changes accordingly.
B)The medulla, 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 to speed up or slow breathing.
E)The medulla is able to control the concentration of bicarbonate ions in the blood.

Question 63

The following questions refer to the data shown below.
Blood entering a capillary bed of a vertebrate was measured for the pressures exerted by various factors.
$$\begin{array} { l c c } & \begin{array} { c } \text { Arterial End of } \\\text { Capillary Bed }\end{array} & \begin{array} { c } \text { Venous End of } \\\text { Capillary Bed }\end{array} \\\hline \text { Hydrostatic pressure } & 10 \mathrm {~mm} \mathrm { Hg } & 14 \mathrm {~mm} \mathrm { Hg } \\\text { Osmotic pressure } & 26 \mathrm {~mm} \mathrm { Hg } & 26 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PO } _ { 2 } & 100 \mathrm {~mm} \mathrm { Hg } & 42 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PCO } _ { 2 } & 40 \mathrm {~mm} \mathrm { Hg } & 46 \mathrm {~mm} \mathrm { Hg }\end{array}$$
Figure 42.1

-How is most of the carbon dioxide transported by the blood in humans?

A)bicarbonate ions in the plasma
B)CO2 attached to hemoglobin
C)carbonic acid in the erythrocytes
D)CO2 dissolved in the plasma
E)bicarbonate attached to hemoglobin

Question 64

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

A)vena cava.
B)left atrium.
C)right atrium.
D)left ventricle
E)right ventricle

Question 65

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

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

Question 66

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
E)the parapodia of a polychaete worm

Question 67

The following questions refer to the data shown below.
Blood entering a capillary bed of a vertebrate was measured for the pressures exerted by various factors.
$$\begin{array} { l c c } & \begin{array} { c } \text { Arterial End of } \\\text { Capillary Bed }\end{array} & \begin{array} { c } \text { Venous End of } \\\text { Capillary Bed }\end{array} \\\hline \text { Hydrostatic pressure } & 10 \mathrm {~mm} \mathrm { Hg } & 14 \mathrm {~mm} \mathrm { Hg } \\\text { Osmotic pressure } & 26 \mathrm {~mm} \mathrm { Hg } & 26 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PO } _ { 2 } & 100 \mathrm {~mm} \mathrm { Hg } & 42 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PCO } _ { 2 } & 40 \mathrm {~mm} \mathrm { Hg } & 46 \mathrm {~mm} \mathrm { Hg }\end{array}$$
Figure 42.1

-How does the hemocyanin of arthropods and molluscs differ from the hemoglobin of mammals?

A)The oxygen dissociation curve for hemocyanin is linear.
B)Hemocyanin carries appreciably more carbon dioxide.
C)Hemocyanin has protein coupled to copper rather than iron.
D)The protein of hemocyanin is not bound to metal.
E)Hemocyanin includes cyanic acid.

Question 68

The following questions refer to the data shown below.
Blood entering a capillary bed of a vertebrate was measured for the pressures exerted by various factors.
$$\begin{array} { l c c } & \begin{array} { c } \text { Arterial End of } \\\text { Capillary Bed }\end{array} & \begin{array} { c } \text { Venous End of } \\\text { Capillary Bed }\end{array} \\\hline \text { Hydrostatic pressure } & 10 \mathrm {~mm} \mathrm { Hg } & 14 \mathrm {~mm} \mathrm { Hg } \\\text { Osmotic pressure } & 26 \mathrm {~mm} \mathrm { Hg } & 26 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PO } _ { 2 } & 100 \mathrm {~mm} \mathrm { Hg } & 42 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PCO } _ { 2 } & 40 \mathrm {~mm} \mathrm { Hg } & 46 \mathrm {~mm} \mathrm { Hg }\end{array}$$
Figure 42.1

-Emphysema is a disease, frequently caused by smoking, that results in loss of the elastic elements of lung tissue. The effect will be more like which of the following?

A)an increase in airway resistance
B)a decrease in airway resistance
C)bronchiolar constriction as in asthma
D)pulmonary edema in which the alveoli amass fluid
E)cystic fibrosis in which mucus builds up in the lungs

Question 69

The conversion of fibrinogen to fibrin

A)occurs when fibrinogen is released from broken platelets.
B)occurs within red blood cells.
C)is linked to hypertension and may damage artery walls.
D)is likely to occur too often in an individual with hemophilia.
E)is the final step of a clotting process that involves multiple clotting factors.

Question 70

The following questions refer to the data shown below.
Blood entering a capillary bed of a vertebrate was measured for the pressures exerted by various factors.
$$\begin{array} { l c c } & \begin{array} { c } \text { Arterial End of } \\\text { Capillary Bed }\end{array} & \begin{array} { c } \text { Venous End of } \\\text { Capillary Bed }\end{array} \\\hline \text { Hydrostatic pressure } & 10 \mathrm {~mm} \mathrm { Hg } & 14 \mathrm {~mm} \mathrm { Hg } \\\text { Osmotic pressure } & 26 \mathrm {~mm} \mathrm { Hg } & 26 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PO } _ { 2 } & 100 \mathrm {~mm} \mathrm { Hg } & 42 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PCO } _ { 2 } & 40 \mathrm {~mm} \mathrm { Hg } & 46 \mathrm {~mm} \mathrm { Hg }\end{array}$$
Figure 42.1

-Birds have negative pressure breathing, but it differs from that of mammals and is more efficient because of which of the following reasons?

A)The bird's mouth movements are able to force air into the lungs.
B)The tidal volume in birds is much larger than in a comparably sized mammal.
C)The maximum PO2 is significantly higher in bird lungs.
D)The flow of air in a bird's lungs is from posterior to anterior.
E)The brain of the bird maximizes oxygen uptake more efficiently.

Question 71

Which of the following reactions prevails in red blood cells traveling through alveolar capillaries? (Hb = hemoglobin)

A)Hb + 4 O2 → Hb(O2)4
B)Hb(O2)4 → Hb + 4 O2
C)CO2 + H₂O → H2CO3
D)H2CO3 → H+ + HCO3-
E)Hb + 4 CO2 → Hb(CO2)4

Question 72

The following questions refer to the data shown below.
Blood entering a capillary bed of a vertebrate was measured for the pressures exerted by various factors.
$$\begin{array} { l c c } & \begin{array} { c } \text { Arterial End of } \\\text { Capillary Bed }\end{array} & \begin{array} { c } \text { Venous End of } \\\text { Capillary Bed }\end{array} \\\hline \text { Hydrostatic pressure } & 10 \mathrm {~mm} \mathrm { Hg } & 14 \mathrm {~mm} \mathrm { Hg } \\\text { Osmotic pressure } & 26 \mathrm {~mm} \mathrm { Hg } & 26 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PO } _ { 2 } & 100 \mathrm {~mm} \mathrm { Hg } & 42 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PCO } _ { 2 } & 40 \mathrm {~mm} \mathrm { Hg } & 46 \mathrm {~mm} \mathrm { Hg }\end{array}$$
Figure 42.1

-Which of the following is a characteristic of both hemoglobin and hemocyanin?

A)found within blood cells
B)red in color
C)contains the element iron as an oxygen-binding component
D)transports oxygen
E)occurs in mammals

Question 73

Pulse is a direct measure of

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

Question 74

The following questions refer to the data shown below.
Blood entering a capillary bed of a vertebrate was measured for the pressures exerted by various factors.
$$\begin{array} { l c c } & \begin{array} { c } \text { Arterial End of } \\\text { Capillary Bed }\end{array} & \begin{array} { c } \text { Venous End of } \\\text { Capillary Bed }\end{array} \\\hline \text { Hydrostatic pressure } & 10 \mathrm {~mm} \mathrm { Hg } & 14 \mathrm {~mm} \mathrm { Hg } \\\text { Osmotic pressure } & 26 \mathrm {~mm} \mathrm { Hg } & 26 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PO } _ { 2 } & 100 \mathrm {~mm} \mathrm { Hg } & 42 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PCO } _ { 2 } & 40 \mathrm {~mm} \mathrm { Hg } & 46 \mathrm {~mm} \mathrm { Hg }\end{array}$$
Figure 42.1

-Hydrogen ions produced in human red blood cells are prevented from significantly lowering pH by combining with

A)hemoglobin.
B)plasma proteins.
C)carbon dioxide.
D)carbonic acid.
E)plasma buffers.

Question 75

The following questions refer to the data shown below.
Blood entering a capillary bed of a vertebrate was measured for the pressures exerted by various factors.
$$\begin{array} { l c c } & \begin{array} { c } \text { Arterial End of } \\\text { Capillary Bed }\end{array} & \begin{array} { c } \text { Venous End of } \\\text { Capillary Bed }\end{array} \\\hline \text { Hydrostatic pressure } & 10 \mathrm {~mm} \mathrm { Hg } & 14 \mathrm {~mm} \mathrm { Hg } \\\text { Osmotic pressure } & 26 \mathrm {~mm} \mathrm { Hg } & 26 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PO } _ { 2 } & 100 \mathrm {~mm} \mathrm { Hg } & 42 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PCO } _ { 2 } & 40 \mathrm {~mm} \mathrm { Hg } & 46 \mathrm {~mm} \mathrm { Hg }\end{array}$$
Figure 42.1

-In an animal species known for endurance running rather than fast sprinting, which of the following would you expect?

A)a slower rate of oxygen consumption so that its breathing will not have to be accelerated
B)an increase of storage of oxygen in myoglobin of its muscles
C)a relatively slow heart rate in order to lower oxygen consumption
D)a lower pressure of oxygen in the alveoli
E)a much higher rate of oxygen consumption for its size

Question 76

The following questions refer to the data shown below.
Blood entering a capillary bed of a vertebrate was measured for the pressures exerted by various factors.
$$\begin{array} { l c c } & \begin{array} { c } \text { Arterial End of } \\\text { Capillary Bed }\end{array} & \begin{array} { c } \text { Venous End of } \\\text { Capillary Bed }\end{array} \\\hline \text { Hydrostatic pressure } & 10 \mathrm {~mm} \mathrm { Hg } & 14 \mathrm {~mm} \mathrm { Hg } \\\text { Osmotic pressure } & 26 \mathrm {~mm} \mathrm { Hg } & 26 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PO } _ { 2 } & 100 \mathrm {~mm} \mathrm { Hg } & 42 \mathrm {~mm} \mathrm { Hg } \\\mathrm { PCO } _ { 2 } & 40 \mathrm {~mm} \mathrm { Hg } & 46 \mathrm {~mm} \mathrm { Hg }\end{array}$$
Figure 42.1

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

A)the partial pressure of oxygen.
B)the partial pressure of carbon monoxide.
C)hemoglobin concentration.
D)temperature.
E)pH.

Question 77

In negative pressure breathing, inhalation results from

A)forcing air from the throat down into the lungs.
B)contracting the diaphragm.
C)relaxing the muscles of the rib cage.
D)using muscles of the lungs to expand the alveoli.
E)contracting the abdominal muscles.

Question 78

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
E)rising CO2 and falling O2