Deck 44: Gas Exchange and Circulation

Question 1

Which of the following events would be predicted by the Bohr shift effect as the amount of carbon dioxide released from your tissues into the blood capillaries increases?

A)The amount of oxygen in arterial blood would increase.
B)The amount of oxygen in arterial blood would decrease.
C)The amount of oxygen in venous blood would increase.
D)The amount of oxygen in venous blood would decrease.
E)More than one of the above is true.

Answer 1

D

Question 2

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.

Answer 2

C

Question 3

The air pressure in Denver,Colorado,is about 83% of the air pressure in Miami Beach,which is about sea level.Given that the air pressure in Miami Beach is 760 mm Hg and oxygen makes up 21% of the air in Miami Beach,what is the percentage of oxygen and the partial pressure of oxygen in Denver,respectively?

A)21%;21 mm Hg
B)21%;132 mm Hg
C)17.4%;132 mm Hg
D)17.4%;21 mm Hg

Answer 3

B

Question 4

Why is the pharmacological reactivation of fetal hemoglobin in a patient with sickle cell anemia often a successful treatment?

A)Fetal hemoglobin binds more oxygen molecules than adult hemoglobin.
B)Fetal hemoglobin is better able to release oxygen than is adult hemoglobin.
C)Fetal hemoglobin has a higher affinity for oxygen than does adult hemoglobin.
D)Fetal hemoglobin is better able to release carbon dioxide than is adult hemoglobin.
E)Fetal hemoglobin has a higher affinity for carbon dioxide than does adult hemoglobin.

Question 5

Why is it more difficult to obtain enough oxygen via respiration from water than from air?

A)The density of water makes ventilating the respiratory tissues more difficult.
B)The viscosity of water is more than that of air.
C)The solubility of oxygen in water is more than in air.
D)The partial pressure of water is higher than that of air.

Question 6

The main difference between respiration in terrestrial insects and in terrestrial vertebrates is that _____.

A)insects rely on the blood in their circulatory system to deliver oxygen from the air to their tissues,whereas terrestrial vertebrates rely on their lungs to deliver oxygen in air to their tissues
B)insects rely on their tracheal system to deliver oxygen in air to their tissues,whereas terrestrial vertebrates rely on their lungs to deliver oxygen to their tissues through the blood in their circulatory system
C)insects have a lower metabolic rate than terrestrial vertebrates do,so they tend to rely more heavily on their circulatory system than their tracheal system for oxygen transport
D)insects use their tracheal system to transfer oxygen from air into blood,whereas terrestrial vertebrates use their lungs to transfer oxygen from air into blood

Question 7

Determine the rate of diffusion in the gas-exchange organ of an air-breathing animal where the area for gas exchange in the lung is 200 mm²,the diffusion constant is 0.08,the PO₂ (partial pressure of oxygen)of the air in the lung is 140 mm Hg,the PO₂ in blood flowing into the lung is 90 mmHg,and the thickness of the gas exchange membrane is 0.001 mm.

A)800,000
B)125
C)00032
D)10,000,000

Question 8

The oxygen content of water increases linearly with increase in oxygen partial pressure while the oxygen content of blood increases in a sigmoidal (S-shaped)fashion.Why?

A)Carbonic anhydrase contributes to CO₂ release in blood,but not water.
B)The Bohr shift is stronger in water than in blood.
C)Hemoglobin shows cooperative oxygen binding.
D)All of the above answers apply.

Question 9

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

A)Airflow through the avian lung is bidirectional.
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 10

When you are jogging,your muscles are using more oxygen and releasing more carbon dioxide into the blood than when you are at home on the couch.Which of the following would occur during your jog?

A)Blood pH would increase by at least 1 pH unit.
B)The concentration of bicarbonate ions (HCO₃⁻)in the blood would decrease.
C)The medullary respiratory center would increase the rate of breathing.
D)All of the above answers apply.

Question 11

If other factors are equal,which of the following environments would have the highest level of dissolved oxygen?

A)warm,salty water at low elevation
B)cool,salty water at low elevation
C)warm freshwater at high elevation
D)cool freshwater at high elevation
E)cool freshwater at low elevation

Question 12

If you were to design a countercurrent exchange respiratory system in fish,which of the following would not be expected?

A)In the front (anterior)portion of the gill,the amount of oxygen in the gills is lower than the water.
B)Water travels over the gills from anterior to posterior.
C)In the back (posterior)portion of the gill,the amount of carbon dioxide in the gills is higher than the water.
D)Blood flows through the gills from anterior to posterior.

Question 13

How does lymph differ between closed and open circulatory systems?

A)In a closed system,lymph is always inside of vessels,whereas in an open system,lymph can escape.
B)In a closed system,lymph travels through a set of vessels separate from blood,whereas in an open system,they never separate.
C)In an open system,all the white blood cells are located in lymph only,whereas in a closed system,they are located in blood only.
D)All of the above answers are true concerning lymph.

Question 14

In what way does hemoglobin act as a buffer against changes in blood pH?

A)Subsequent binding of oxygen is drastically reduced after the first one is bound.
B)Hemoglobin binds some of the excess protons released by carbonic acid.
C)Hemoglobin produces protons or hydroxide ions as needed to alter the blood pH.
D)Hemoglobin removes excess protons from the red blood cells so that they can be excreted through the kidneys.
E)All of the above answers apply.

Question 15

When the sea lamprey (Petromyzon marinus),a marine jawless fish,was moved in the ballast of ships from the Atlantic to the Great Lakes (a freshwater environment)the fish could more easily obtain oxygen from freshwater than it could in its native marine habitat.Why is this the case?

A)Freshwater has more oxygen than seawater.
B)Oxygen is more soluble in freshwater than in seawater.
C)Freshwater is colder than seawater.
D)Partial pressure of freshwater is higher than the partial pressure of seawater.
E)None of the above apply.

Question 16

Fick's law of diffusion describes the factors that influence the diffusion of respiratory gases across biological membranes like gills and lungs.Diffusion rate = k × A × (P₂ - P₁)/D.Natural selection is least likely to act upon which variable in Fick's law?

A)A
B)k
C)P₂ - P₁
D)D

Question 17

Which of the following statements supports the hypothesis that the bidirectional gas flow occurring in humans (air goes in and out through the same passages)is less efficient than the unidirectional flow in fish?

A)Bidirectional flow in humans does not take advantage of countercurrent exchange.
B)About one-third of the air in human lungs is trapped in "dead space" where gas exchange with the circulation cannot occur.
C)Neither "bidirectional flow in humans does not take advantage of countercurrent exchange" nor "about one-third of the air in human lungs is trapped in 'dead space' where gas exchange with the circulation cannot occur" is true.
D)Bidirectional flow in humans does not take advantage of countercurrent exchange;about one-third of the air in human lungs is trapped in "dead space" where gas exchange with the circulation cannot occur.

Question 18

What adaptations are observed in trachea and lungs to reduce water loss?

A)A countercurrent exchange system reduces water loss in animals with either trachea or lungs.
B)The location of the trachea and lungs (inside of the body)reduces water loss.
C)Trachea and lungs secrete specialized oxygen-carrying chemicals to reduce water loss.
D)Limbs are used by animals with trachea or lungs to move water over these structures.

Question 19

Which of the following best describes the process of ventilation?

A)the movement of oxygen gas through the blood of the circulatory system
B)the movement of carbon dioxide gas through the blood of the circulatory system
C)the movement of air through lungs or gills
D)the diffusion of gases into and out of the circulatory system
E)the diffusion of gases into and out of tissues where cellular respiration occurs

Question 20

You prop open the gill covers of a fish,tie a string around its tail,and tow it backward through the water.This action forces water to flow in the back of the gill covers,from back to front over the gills,and out through the fish's mouth.What effect would this backward movement have on gas exchange?

A)It would reduce efficiency of gas exchange.
B)It would change from CO₂ out and O₂ in to CO₂ in and O₂ out.
C)There would be no change in the efficiency of gas exchange.

Question 21

Which of the four muscular chambers of the human heart directly propels blood into the pulmonary circulation?

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

Question 22

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)All of the above answers apply.

Question 23

Which of the following mechanisms play(s)a role in regulating heart rate?

A)chemical messengers in the blood,such as epinephrine
B)nerves originating from the medulla (lower part of the brain)
C)pacemaker cells within the heart
D)chemical messengers in the blood,such as epinephrine;nerves originating from the medulla (lower part of the brain);and pacemaker cells within the heart
E)chemical messengers in the blood,such as epinephrine,and pacemaker cells within the heart

Question 24

A large increase in albumin concentration in the plasma of a dog would result in which of the following?

A)increase in blood volume and decrease in lymph volume
B)decrease in blood volume and increase in lymph volume
C)increase in blood volume and increase in lymph volume
D)decrease in blood volume and decrease in lymph volume

Question 25

In a cross section through an artery and vein running parallel in your leg,which would be the artery?

A)the vessel with the largest interior diameter
B)the vessel with more muscle tissue in the wall
C)the vessel lined with endothelium
D)the vessel with valves to prevent backflow
E)All of the above answers apply.

Question 26

Atria contract _____.

A)just prior to the beginning of diastole
B)during diastole
C)immediately after systole
D)during systole

Question 27

What is the QRS complex in an ECG tracing?

A)ventricular depolarization
B)depolarization spreading from the SA node throughout the atria
C)ventricular repolarization
D)the time for both ventricular depolarization and repolarization to occur
E)one full cardiac cycle

Question 28

You are a physician,and you are seeing a patient who complains of abnormal fatigue during exercise.You find that the immediate problem is a buildup of carbon dioxide in the tissues.What is the most likely cause?

A)abnormally shaped platelets
B)abnormal carbonic anhydrase
C)abnormal hemoglobin
D)not enough hemoglobin

Question 29

Use the following information when answering the corresponding question(s).
Lymph hearts are pumping structures that drive lymph through the lymphatic system,returning it to the circulatory system at the large veins entering the heart.Researchers examined rate and strength of pumping of lymph hearts in two species of amphibians,a toad (Bufo marinus)and a frog (Rana catesbiana).During hemorrhage or dehydration,the volume of blood in the circulatory system falls.A hormone,arginine vasotocin (AVT),is released in these situations.The researchers examined the effect of AVT on lymph heart function.They found that AVT increased pressure at the lymph heart but did not affect the rate of lymph heart pumping.They also examined the effect of atrial natriuretic peptide (ANP),a hormone that is released when blood volume is higher than normal.(E.A.DeGrauw and S.S.Hillman.2004.General function and endocrine control of the posterior lymph hearts in Bufo marinus and Rana catesbiana.Physiological and Biochemical Zoology 77(4):594-600. )
Refer to the paragraph on lymph hearts.If atrial natriuretic peptide (ANP)has an effect on the lymph hearts,what effect would logically be predicted?

A)Lymph heart rate would increase.
B)Lymph heart rate would decrease.
C)Lymph heart pressure would increase.
D)Lymph heart pressure would decrease.

Question 30

Which of the following mechanisms are used to regulate blood pressure in the closed circulatory system of vertebrates?

A)changing the force of heart contraction
B)constricting and relaxing sphincters in the walls of arterioles
C)adjusting the volume of blood contained in the veins
D)all of the above

Question 31

An animal has a cardiac output of 40 mL/min and a stroke volume of 5 mL.What is its heart rate?

A)8 beats/minute
B)200 beats/minute
C)12.5 beats/minute
D)Heart rate cannot be determined with only these two variables.

Question 32

Which of the following is the correct sequence of terms describing fluid movement throughout the vessels and tissues of the body,starting with the circulatory system?

A)blood → lymph → blood → interstitial fluid
B)blood → lymph → interstitial fluid → blood
C)blood → interstitial fluid → lymph → blood
D)blood → interstitial fluid → blood → lymph

Question 33

Baroreceptors are specialized pressure-sensing nerve cells that are important in circulatory homeostasis.Where are these nerve cells located in humans?

A)cells in brain
B)arteries entering the neck region
C)arteries leaving the heart
D)cells in the brain,arteries entering the neck region,and arteries leaving the heart
E)arteries entering the neck region and arteries leaving the heart

Question 34

Baroreceptors sensing a rapid increase in blood pressure will likely result in _____.

A)reduced cardiac output
B)increased cardiac output
C)constricted arterioles and veins
D)reduced cardiac output and constricted arterioles and veins
E)increased cardiac output and constricted arterioles and veins

Question 35

Which of the following conditions would be the most likely result of an abnormally high blood pressure in an animal like a reptile possessing a closed circulatory system?

A)hemorrhage in the capillary beds
B)hemorrhage in the aorta
C)reversal of normal blood flow direction in the veins
D)all of the above

Question 36

Use the following information when answering the corresponding question(s).
Lymph hearts are pumping structures that drive lymph through the lymphatic system,returning it to the circulatory system at the large veins entering the heart.Researchers examined rate and strength of pumping of lymph hearts in two species of amphibians,a toad (Bufo marinus)and a frog (Rana catesbiana).During hemorrhage or dehydration,the volume of blood in the circulatory system falls.A hormone,arginine vasotocin (AVT),is released in these situations.The researchers examined the effect of AVT on lymph heart function.They found that AVT increased pressure at the lymph heart but did not affect the rate of lymph heart pumping.They also examined the effect of atrial natriuretic peptide (ANP),a hormone that is released when blood volume is higher than normal.(E.A.DeGrauw and S.S.Hillman.2004.General function and endocrine control of the posterior lymph hearts in Bufo marinus and Rana catesbiana.Physiological and Biochemical Zoology 77(4):594-600. )
Refer to the paragraph on lymph hearts.What effect would increasing lymph heart pressure have?

A)Blood volume would increase.
B)Blood volume would decrease.
C)Hemorrhage would increase.
D)Hemorrhage would decrease.
E)None of the above answers apply.

Question 37

Carbonic anhydrase inhibitors cause less movement of carbonic acid toward CO₂ production and are used as a prophylactic treatment of altitude sickness.Altitude sickness occurs when a hiker ascends to altitudes where the density of oxygen is low.How does this decrease the symptoms of high altitude sickness?

A)The excess hydrogen ions are excreted in the urine and the resulting loss of acidity increases respiration rate.
B)The excess bicarbonate ions are excreted in the urine and the resulting loss of blood pressure increases respiration rate.
C)The excess bicarbonate ions are excreted in the urine and the resulting increase in blood acidity leads to an increase in ventilation.
D)The excess bicarbonate ions in the blood stimulate the production of more red blood cells.
E)The excess bicarbonate ions in the blood increase the affinity of hemoglobin for oxygen.