Chapter 42 Terms
59) Atmospheric pressure at sea level is equal to a column of 760 mm Hg. Oxygen makes up 21% of the atmosphere by volume. The partial pressure of oxygen (PO₂) in such conditions is
A) 160 mm Hg.
20) A stroke volume in the heart of 70 mL/cycle, with a pulse of 72 cycles per minute, results in a cardiac output of
A) 5 L/minute.
90) Which of the following reactions prevails in red blood cells traveling through alveolar capillaries? (Hb = hemoglobin)
A) Hb + 4 O₂ → Hb(O₂)₄
63) The exhalation of air from human lungs is driven by
A) a decrease in the volume of the thoracic cavity.
76) Most of the carbon dioxide produced by humans is
A) converted to bicarbonate ions by an enzyme in red blood cells.
34) Dialysis patients, who will have blood withdrawn, dialyzed, then replaced, are always weighed when they enter the facility and then weighed carefully again before they leave, because
A) even small changes in body weight may signify changes in blood volume and therefore blood pressure.
77) Hydrogen ions produced within human red blood cells are prevented from significantly lowering plasma pH because they bind to
A) hemoglobin.
89) Compared with the interstitial fluid that bathes active muscle cells, blood reaching these cells in arteries has a
A) higher PO₂.
27) Small swollen areas in the neck, groin, and axillary region are associated with
A) increased activity of the immune system.
42) The plasma proteins in humans
A) maintain the blood's osmotic pressure.
55) Countercurrent exchange is evident in
A) the flow of water across the gills of a fish and that of blood within those gills.
14) Which of the following pairs of mammalian blood vessels has blood that is the least similar in its gas content?
A) the pulmonary vein and the jugular vein
88) 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.
62) Air rushes into the lungs of humans during inhalation because
A) the rib muscles and diaphragm contract, increasing the lung volume.
64) As a person goes from rest to full-effort exercise, there is an increase in the
A) tidal volume.
70) At the summit of a high mountain, the atmospheric pressure is 380 mm Hg. If the atmosphere is still composed of 21% oxygen, then the partial pressure of oxygen at this altitude is
B) 80 mm Hg.
8) Organisms with a circulating body fluid that is distinct from the fluid that directly surrounds the body's cells are likely to have
B) a closed circulatory system.
49) The sun shining on a tidal pool during a hot day heats the water. As some water evaporates, the pool becomes saltier, causing
B) a decrease in its oxygen content.
72) An increase from pH 7.2 to pH 7.4 around hemoglobin causes
B) an increase in the affinity of hemoglobin to bind oxygen molecules.
81) An anthropologist discovers the fossilized heart of an extinct animal. The evidence indicates that the organism's heart was large, 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
B) animal was endothermic and had a high metabolic rate.
58) An oil-water mixture works as an insecticidal spray against mosquitoes and other insects because it
B) blocks the openings into the tracheal system.
35) Large proteins such as albumin remain in capillaries rather than diffusing out, resulting in the
B) development of an osmotic pressure difference across capillary walls.
40) The hormone that stimulates the production of red blood cells, and the organ where this hormone is synthesized, are
B) erythropoietin and kidney, respectively.
46) The meshwork that forms the fabric of a blood clot is
B) fibrin.
31) If, during protein starvation, the osmotic pressure on the venous side of capillary beds drops below the hydrostatic pressure, then
B) fluids will tend to accumulate in tissues.
84) Blood returning to the mammalian heart in a pulmonary vein drains first into the
B) left atrium.
38) Among these choices, the biggest set that includes only those "cells" that lack nuclei is
B) platelets and erythrocytes.
82) A group of students was designing an experiment to test the effect of smoking on grass frogs. They hypothesized that keeping the frogs in a smoke-filled environment for defined periods would result in the animals developing lung cancer. 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 of putting carcinogens in the air would be the development of
B) skin cancer.
51) Flying insects do all of the following except
B) switch from diffusion of tracheal gases to active transport during flight.
61) Of the following choices, impairment of a mammal's breathing cycle is most likely following neural damage in
B) the medulla oblongata and the pons.
71) Carbon dioxide levels in the blood and cerebrospinal fluid affect its pH. This enables the organism to sense a disturbance in gas levels as
B) the medulla oblongata, which is in contact with cerebrospinal fluid, monitors pH and uses this measure to control breathing.
6) The circulatory system of bony fishes, rays, and sharks is similar to
B) the portal systems of mammals, where two capillary beds occur sequentially, without passage of blood through a pumping chamber.
2) Circulatory systems have the primary benefit of overcoming the shortcomings of
B) the slow rate at which diffusion occurs across cells.
16) 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 in the arm to the left ventricle, this red blood cell must pass through
B) two capillary beds.
25) An increased concentration of nitric oxide within a vascular bed is associated with
B) vasodilation.
54) Gas exchange is more difficult for aquatic animals with gills than for terrestrial animals with lungs because
B) water contains much less O₂ than air per unit volume.
48) 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
C) 40 mm Hg.
41) Dissolved proteins in human plasma include which of the following? I. fibrinogen II. hemoglobin III.immunoglobulin
C) I and III only
7) A significant increase in the amount of interstitial fluid surrounding the capillary beds of a human's lungs will cause
C) a decrease in the amount of oxygen moving from the lungs into the blood.
47) A normal event in the process of blood clotting is the
C) activation of prothrombin to thrombin.
56) Countercurrent exchange in the fish gill helps to maximize
C) diffusion.
45) The production of red blood cells is stimulated by
C) erythropoietin.
10) The only vertebrates in which blood flows directly from respiratory organs to body tissues without first returning to the heart are the
C) fishes.
78) The hemocyanin of arthropods and molluscs differ from the hemoglobin of mammals in that
C) hemocyanin has protein coupled to copper rather than iron.
86) When you hold your breath, which of the following blood gas changes first leads to the urge to breathe?
C) rising CO₂
36) Vasoconstriction in the gut is a likely response when an individual is
C) stressed and secreting stress hormones.
52) The epiglottis of a human covers the glottis when he or she is
C) swallowing.
13) Which of the following develops the greatest pressure on the blood in the mammalian aorta?
C) systole of the left ventricle
32) What will be the long-term effect of blocking the lymphatic vessels associated with a capillary bed?
C) the accumulation of more fluid in the interstitial areas
30) Fluid is filtered out of the bloodstream into the surrounding interstitial fluid at the arteriole end of systemic capillaries because
C) the hydrostatic pressure of the blood is greater than the osmotic pressure of the blood.
15) After several weeks of exercise, a human athlete's resting heart rate is typically lower than before because
C) the stroke volume has increased.
83) Which of the following respiratory systems is not closely associated with a blood supply?
C) the tracheal system of an insect
69) At sea level, atmospheric pressure is 760 mm Hg. Oxygen gas is approximately 21% of the total gases in the atmosphere, so the approximate partial pressure of oxygen is
D) 160.0 mm Hg.
68) At an atmospheric pressure of 870 mm Hg of 21% oxygen, the partial pressure of oxygen is
D) 182 mm Hg.
18) 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
D) 2,800 mL/minute.
65) 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
D) 5,000 mL
67) Breathing is usually regulated by
D) CO₂ and O₂ concentration and pH-level sensors.
57) Air-breathing insects carry out gas exchange
D) across the membranes of their cells.
33) A species that has a normal resting systolic blood pressure of >260 mm Hg is likely to be
D) an animal that has a very long distance between its heart and its brain.
5) Circulatory systems in molluscs
D) are open in species of small-sized molluscs and are closed in species of large-sized molluscs.
37) The diagnosis of hypertension in adults is based on the
D) blood pressure being greater than 140 mm Hg systolic and/or >90 diastolic.
74) Hemoglobin and hemocyanin
D) both transport oxygen.
66) During most daily activities, the human respiration rate is most closely linked to the blood levels of
D) carbon dioxide.
22) The material present in arterioles that is not present in capillaries is
D) circular smooth muscle cells that can alter the size of the arterioles.
44) Heart rate will increase in the presence of increased
D) epinephrine.
39) In a healthy human, the typical life span of a red blood cell is
D) four months.
9) In which of the following organisms does blood flow from the pulmocutaneous circulation to the heart before circulating through the rest of the body?
D) frogs
85) Pulse is a direct measure of
D) heart rate.
60) Some human infants, especially those born prematurely, suffer serious respiratory failure because of
D) lung collapse due to inadequate production of surfactant.
21) The semilunar valves of the mammalian heart
D) prevent backflow of blood in the aorta and pulmonary arteries.
1) Gas exchange in the aquatic salamander known as the axolotl is correctly described as
D) simple diffusion of oxygen into the salamander from the water.
23) The set of blood vessels with the slowest velocity of blood flow is
D) the capillaries.
87) One feature that amphibians and humans have in common is
D) the number of circuits for circulation.
17) Which of the following is the correct sequence of blood flow in reptiles and mammals?
D) vena cava → right atrium → right ventricle → pulmonary circuit
19) Damage to the sinoatrial node in humans
D) would disrupt the rate and timing of cardiac muscle contractions.
79) In an animal species known for endurance running rather than fast sprinting, you would expect to find
E) a much higher rate of oxygen consumption for its size.
12) A portal system is
E) a vessel or vessels connecting two capillary beds.
53) In mammals, most gas exchange between the atmosphere and the pulmonary blood occurs in the
E) alveoli.
43) 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
E) be unaffected.
3) To become bound to hemoglobin for transport in a mammal, atmospheric molecules of oxygen must cross
E) five membranesin and out of the cell lining the lung, in and out of the endothelial cell lining the pulmonary capillary, and into the red blood cellto bind with hemoglobin.
Blood entering a capillary bed of an unusual vertebrate was measured for the pressures exerted by various factors, as shown in Figure 42.1. Figure 42.1 80) For this unusual capillary bed,
E) fluids will leave the capillaries on the arterial side of the bed and re-enter on the venous side.
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)
E) four-chambered heart.
26) Among the following choices, which organism likely has the highest systolic pressure?
E) giraffe
73) An "internal reservoir" of oxygen in rested muscle is found in oxygen molecules bound to
E) myoglobin.
50) Sponges, cnidarians, and flatworms lack a specialized gas exchange surface because
E) nearly all of their cells are in direct contact with the external environment.
75) The Bohr shift on the oxygen-hemoglobin dissociation curve is produced by changes in
E) pH.
4) The fluid that moves around in the circulatory system of a typical arthropod is
E) the interstitial fluid.
28) The velocity of blood flow is the lowest in capillaries because
E) 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.
24) The set of blood vessels with the lowest blood pressure driving flow is
E) the veins.
29) The blood pressure is lowest in the
E) venae cavae.
