Deck 28: Circulation and Gas Exchange

Question 1

Inhaled air passes through a number of organs on its way to the alveoli;into which organ does it enter immediately after leaving the nasal cavity?

A) the bronchi
B) the alveoli
C) the lung
D) the pharynx

Answer 1

D

Question 2

Which of the following would have the smallest diameter?

A) the pharynx
B) the trachea
C) the bronchi
D) the bronchioles

Answer 2

D

Question 3

In what way,if any,is the cardiovascular system of humans important to the process of gas exchange?

A) It has no importance;gas exchange is a function of the respiratory system.
B) It forms a passageway that allows air to be taken into the lungs.
C) It increases the area available for gas exchange.
D) It transports oxygen to cells that are not in direct contact with air.

Answer 3

D

Question 4

The figures shows a fragment of a clot separating and moving downstream in the venous system.When the clot encounters a vessel with a diameter smaller than itself it will become lodged and the flow of blood will be blocked.Where is this most likely to happen?

A) in the aorta
B) in the arteries or arterioles of the lung
C) in the right atrium or right ventricle
D) in the left atrium or left ventricle

Question 5

Cystic fibrosis is a genetic disease whose symptoms include failure of the ciliary system that clears trapped dust and bacteria from the respiratory system,resulting in incessant coughing and an inability to exert or exercise.Which respiratory structure is most likely affected?

A) the alveoli
B) the bronchi and bronchioles
C) the diaphragm
D) the larynx

Question 6

Which organ connects the pharynx to the bronchi?

A) the trachea
B) the alveoli
C) the bronchioles
D) the tracheoles

Question 7

Gas transport moves oxygen through many locations and fluids,but its ultimate destination is the

A) alveoli.
B) lungs.
C) cells of the body.
D) mitochondria.

Question 8

Average human lung capacity is 6 L,but a typical breath is only about 400 ml;inhaled air only directly reaches the bronchi.How does the oxygen get from the bronchi to the alveoli?

A) It's transported by the blood in the bronchi and delivered to the alveoli.
B) The next inhalation moves it a little closer-by the ninth or tenth inhalation it has reached the alveoli.
C) It diffuses down the bronchioles because its concentration in the alveoli is low.
D) Oxygen molecules are relatively heavy;they simply flow under the influence of gravity down into the alveoli.

Question 9

A typical human blood pressure is 120/80.Since the heart is NOT pumping during diastole,how is it possible that the diastolic pressure is as high as 80 rather than falling to 0?

A) Muscle tone,the small continuous contractions of resting muscle,maintains enough compression on the blood vessels to produce the low diastolic pressure.
B) The elastic walls of the arteries are stretched during systole;they recoil during diastole,compress the blood,and keep it pressurized until the next heartbeat.
C) Valves in the veins open and close to produce a secondary pumping that operates independently of the heart.
D) The pressure during diastole is produced by gravity and the weight of the blood;diastolic pressures are highest in the feet (120/120)and lowest in the brain (120/0).

Question 10

The cluster of cells commonly referred to as the "pacemaker" is known to anatomists as the

A) atrioventricular (AV)node.
B) sino atrial (SA)node.
C) atrium.
D) ventricle.

Question 11

During the standard cardiac cycle,blood passes through four different valves.Some newborns suffer from a structural defect that forms an open passage between the atria;what valves would be bypassed in this condition?

A) the left atrium/ventricle valve and the right ventricle/artery valve
B) the left atrium/ventricle valve and the left ventricle/artery valve
C) the right atrium/ventricle valve and the right ventricle/artery valve
D) the right atrium/ventricle valve and the left ventricle/artery valve

Question 12

At any given moment what is the approximate percentage of total blood pumped per minute that enters the pulmonary circuit and the systemic circuit?

A) 20 percent to pulmonary,80 percent to systemic
B) 30 percent to pulmonary,70 percent to systemic
C) 40 percent to pulmonary,60 percent to systemic
D) 50 percent to pulmonary,50 percent to systemic

Question 13

The image below illustrates a fatty plague,the blood clot it initiated,and a severely reduced opening (or lumen)through which the blood must travel.This condition is termed

A) systemic thrombosis.
B) atherosclerosis.
C) pulmonary thrombosis.
D) circulatory fibromatosis.

Question 14

In comparison to the air in the alveoli,inhaled air has a

A) higher concentration of carbon dioxide and a lower concentration of oxygen.
B) higher concentration of both carbon dioxide and oxygen.
C) higher concentration of oxygen and a lower concentration of carbon dioxide.
D) lower concentration of both carbon dioxide and oxygen.

Question 15

Inhaled air reaches the lungs after passing through a paired set of organs,the

A) bronchi.
B) alveoli.
C) bronchioles.
D) pharynx.

Question 16

Which of the following statements about the surface area available for gas exchange is true?

A) When standardized for body mass all organisms are approximately equal.
B) Internal partitioning of a lung reduces its volume and makes gas exchange less efficient.
C) The surface area is positively correlated with the level of metabolic activity.
D) Since active mammals have a higher respiration rate,the area available for gas exchange can be smaller than that of less active mammals with lower respiration rates.

Question 17

Patients with hypertension are encouraged to reduce the amount of salt they consume;in what way is salt consumption and hypertension related?

A) Ingested salt quickly enters the blood plasma and exerts an osmotic effect that leads to an increase in plasma volume and an elevation in blood pressure.
B) Salt has an osmotic effect,causing water to leave the plasma and enter the stomach;this thickens the remaining plasma and elevates the blood pressure.
C) Salt,in some individuals,mimics the hormone that signals blood vessels to constrict;as they do so the blood is compressed and the blood pressure is elevated.
D) As the solute concentration of any solution increases,the viscosity of the solution increases as well;a more viscous blood creates an elevated pressure.

Question 18

Which of the following describes the journey of a molecule of oxygen from the atmosphere to an alveolus?

A) nasal cavity $\rarr$ pharynx $\rarr$ larynx $\rarr$ trachea $\rarr$ bronchus $\rarr$ bronchiole $\rarr$ alveolus
B) nasal cavity $\rarr$ larynx $\rarr$ pharynx $\rarr$ trachea $\rarr$ bronchus $\rarr$ bronchiole $\rarr$ alveolus
C) nasal cavity $\rarr$ pharynx $\rarr$ larynx $\rarr$ trachea $\rarr$ bronchiole $\rarr$ bronchus $\rarr$ alveolus
D) nasal cavity $\rarr$ trachea $\rarr$ pharynx $\rarr$ larynx $\rarr$ bronchiole $\rarr$ bronchus $\rarr$ alveolus

Question 19

In the figure below,the arrow is pointing to the

A) bronchus.
B) trachea.
C) diaphragm.
D) larynx.

Question 20

What action best describes the action occurring when the rib cage lifts upward and the diaphragm moves downward?

A) coughing
B) inhalation
C) expiration
D) sneezing

Question 21

The genetic disorder sickle-cell anemia develops because the hemoglobin molecule is deformed.Afflicted individuals often suffer muscle pain,even at low levels of exertion.A reasonable hypothesis for the symptoms is that the deformed hemoglobin

A) is unable to carry the amount of oxygen required for normal muscle activity.
B) cannot diffuse across the red blood cell membranes to the blood plasma,causing an oxygen shortage.
C) causes damage to muscle proteins as it diffuses into the muscle cell.
D) damages the alveolar surfaces and decreases the total surface area available for gas exchange.

Question 22

As a compensation for high altitude,it would be common to observe all of the following EXCEPT an

A) increased heart rate and pulmonary blood flow.
B) increase in the concentration of hemoglobin in the blood.
C) increased respiratory rate.
D) increased binding affinity between hemoglobin and oxygen.

Question 23

Patients with the respiratory disease emphysema lose the elasticity of their alveoli;their efforts to exhale can collapse the bronchioles and cause the alveoli to rupture.How might this disease affect the carbon dioxide content of their blood?

A) It would decrease because with less oxygen available less carbon dioxide would be produced.
B) It would increase because there would be more pressure in the lungs that would force the carbon dioxide to dissolve in the blood.
C) It would decrease because the high level of oxygen in the blood would block the carbon dioxide binding sites.
D) It would increase because their lungs have less surface area available for diffusion.

Question 24

How does an actively respiring mitochondrion gain the oxygen it needs to continue its metabolism?

A) Oxygenated hemoglobin crosses the cell membrane,docks to receptors on the mitochondrion's surface,and delivers its oxygen.
B) Cells have internal pigment molecules that collect the oxygen released by hemoglobin and transport it within the cytosol.
C) Because it is consuming oxygen in chemical reactions the mitochondrial oxygen concentration is low;oxygen simply diffuses in.
D) The mitochondrial enzymes can reprocess carbon dioxide back to molecular oxygen to maintain its metabolism.

Question 25

There are actually two gas exchange events: one occurs in the lung and the other occurs when the blood is in a capillary surrounded by active cells.Which statement best summarizes this second exchange?

A) Oxygen diffuses out of the alveoli while carbon dioxide diffuses into the alveoli.
B) Oxygen diffuses into the blood plasma while carbon dioxide diffuses out of the blood plasma.
C) Oxygen diffuses into the alveoli while carbon dioxide diffuses out of the alveoli.
D) Oxygen diffuses out of the blood plasma while carbon dioxide diffuses into the blood plasma.

Question 26

Carbon dioxide

A) is carried by carboxy-carotenoid,the other gas pigment in the blood.
B) is converted to the highly soluble bicarbonate ion and dissolves in the plasma for its journey to the lung.
C) moves from regions of cellular respiration to the alveoli dissolved in the cytoplasm of red blood cells.
D) attaches to hemoglobin and causes structural changes that strengthen the oxygen binding,ensuring that more oxygen is collected when the metabolic level is high.

Question 27

Considering that oxygen is a polar molecule and that its solubility is inversely proportional to temperature,it is most likely that the habitat with the lowest concentration of oxygen would be

A) a lake covered by a sheet of ice.
B) air at sea level.
C) the surf zone along a rocky shoreline.
D) a pond during summer.

Question 28

When blood flowing in a pulmonary capillary first arrives at an alveolus,the concentration of

A) oxygen will be lower in the alveolus than in the blood plasma.
B) carbon dioxide will be greater in the alveolus than in the blood plasma.
C) carbon dioxide will be greater in the blood plasma than in the alveolus.
D) carbon dioxide in the blood plasma will be approximately equal to its concentration in the alveolus.

Question 29

Examine the table below.

Because swimming requires large amounts of ATP and ATP synthesis requires oxygen,which fish is most likely to be the fastest swimmer?

A) the rudderfish
B) the eel
C) the flounder
D) the goosefish

Question 30

Which statement accurately describes the pathway an oxygen molecule follows as it moves through the lung to the blood?

A) It travels from an alveolus to a bronchiole to a capillary to a red blood cell to hemoglobin.
B) It travels from a bronchiole to an alveolus to a capillary to hemoglobin to a red blood cell.
C) It travels from a bronchiole to an alveolus to a capillary to a red blood cell to hemoglobin.
D) It travels from a bronchiole to an alveolus to a red blood cell to a capillary to hemoglobin.

Question 31

Oxygen molecules are polar and dissolve so poorly in blood plasma that there is NOT enough oxygen to meet the metabolic demands of a vertebrate.However,red blood cells contain ________,which greatly increases the oxygen content of blood.

A) carbon dioxide
B) alveoli
C) nodules
D) hemoglobin

Question 32

The figure below illustrates distance and diffusion time;note that the time required is NOT directly proportional to the distance.Why,for the insect and mouse,might an increase in distance of 20-fold require an increase in time of 60-fold?

A) Oxygen reacts chemically as it diffuses,becoming less diffusible as it travels greater distances.
B) Larger animals are warmer than small animals;the rate of diffusion is dependent,in part,on the temperature.
C) As oxygen disperses into a large area,its concentration declines;the rate of diffusion is dependent,in part,on the difference in concentration between two locations.
D) Organisms are able to manipulate the rate of diffusion so that the delivery of oxygen matches their metabolic activity levels.

Question 33

Which of the following statements about the oxygen-binding pigments in mammals is INCORRECT?

A) The pigments are dissolved in the plasma portion of the blood.
B) The pigments significantly increase the oxygen-transporting capacity of the blood.
C) The pigments consist of protein components and a complex containing iron.
D) The pigments bind oxygen when its concentration is high and release it when the concentration is low.

Question 34

Blood in a capillary leaving a nearby cell would contain

A) a lower concentration of carbon dioxide than when it arrived.
B) a higher concentration of carbon dioxide than when it arrived.
C) a higher concentration of oxygen than when it arrived.
D) less hemoglobin than when it arrived.

Question 35

Whether sleeping or exercising,the rate of gas exchange is precisely matched to the body's immediate respiratory needs;gas exchange during exercise,for example,increases because

A) when muscle contracts,the adjacent capillaries are compressed,forcing the gases out and into the surrounding tissues.
B) active cells are warmer than resting cells.
C) the rate of diffusion is proportional to the gas concentration gradients that are high during exercise and low during rest.
D) the elevated blood pressures during activity expands the capillaries,which increases the surface area available for gas exchange.

Question 36

At altitudes above 10,000 feet the thinner air and reduced concentration of atmospheric gases begin to have an effect on many individuals,who may feel light-headed or nauseated because

A) the low pressure of the inhaled air is insufficient to fully expand the lungs.
B) the amount of hemoglobin in the blood naturally declines at higher altitude.
C) hemoglobin becomes denatured at higher altitudes and cannot effectively bind to oxygen.
D) the diffusion gradient between the atmosphere and blood plasma is so low the blood is unable to become fully oxygenated.

Question 37

Hemoglobin

A) is an enzyme involved in the process of cellular respiration.
B) transports oxygen from cells undergoing cellular respiration to red blood cells.
C) binds to oxygen and releases it near cells performing cellular respiration.
D) makes the blood more acidic,enabling it to absorb more oxygen.

Question 38

The concentration of oxygen in normal exhaled air

A) is zero because all the oxygen is transferred to red blood cells and plasma in the lung.
B) will be approximately that of the blood plasma;if it were less the oxygen would diffuse from the plasma back into the alveoli.
C) will always be the reciprocal of the carbon dioxide concentration.
D) is typically a few percent less than the oxygen concentration of the inhaled air.

Question 39

Although often drawn symmetrically,the wall of the right ventricle is actually much thinner than that of the left and is able to generate only about one-quarter of the pressure.Why might this still be physiologically acceptable?

A) The lung is a single organ;systemic circulation requires higher pressures because the blood travels through several organs in sequence,with small drops in pressure in each.
B) The resistance to blood flow in the lung is much less than in the body's other organs.
C) The lungs are at the approximate level of the heart,so gravity is not a factor in pulmonary circulation.
D) The narrow capillaries where most friction is generated are absent in the lung.

Question 40

It's very rare for two sets of capillaries to occur in sequence;what physiological challenge could occur in such a situation?

A) All the pressure that maintains blood flow would be depleted in the first capillary set.
B) Blood arriving at a capillary with a low oxygen concentration would pull oxygen from the cells rather than deliver it.
C) Signaling molecules (a hormone,for example)would be removed at the first capillary;the more distant cells could not be regulated.
D) The combined production of carbon dioxide from twice as many cells would irreparably damage the red blood cell.

Question 41

The cell fragments circulating in blood that can clump together and block blood flow at sites of injury are called ________.

Question 42

The term respiration is used in several contexts;when combined with cellular it refers to the consumption of oxygen,the generation of carbon dioxide,and the synthesis of ATP that occurs in the ________.

Question 43

Many older individuals feel faint from low blood flow to the brain if they stand up too quickly after lying down.What is the most reasonable explanation for how this problem develops?

A) The heart rate fails to increase quickly enough to provide the extra pressure needed to push the blood against gravity.
B) The muscles in the arteries and arterioles are relaxed and fail to constrict quickly enough to maintain the appropriate blood pressure.
C) The respiratory rate fails to increase quickly enough to provide the extra oxygen needed.
D) The bloodstream fails to release new red blood cells quickly enough to handle the extra demands.

Question 44

Hemoglobin,like many other oxygen-binding pigments,contains the metallic element ________.

Question 45

In addition to ethical consideration,artificially increasing the quantity of red blood cells is dangerous;some athletes have suffered ________ after taking drugs like EPO.

A) nausea,vomiting,and dehydration
B) difficulty perspiring and subsequent heatstroke
C) decreased muscle mass
D) high blood pressure,caused by extra blood cells,and heart attack or blood vessel rupture

Question 46

Unlike aquatic organisms,most terrestrial vertebrate exchange respiratory gases internally using a physiologically complicated respiratory system.What benefits does breathing atmospheric air have relative to extracting dissolved gases from the water?

A) Parasites are less likely to gain access through inhalation.
B) The concentration of atmospheric oxygen is much greater than what can dissolve in water.
C) Carbon dioxide reacts with water to form an acid that can accumulate and damage the habitat.
D) The energy content of oxygen is reduced when the molecule interacts with water.

Question 47

Gases diffuse from an area of ________ concentration to an area of ________ concentration.

Question 48

The rate of gas diffusion when the surface area is ________ will be greater than when the surface area is ________.

Question 49

What status would you assign to an individual whose resting blood pressure was consistently 137/78?

A) low or hypotensive
B) ideal
C) pre-high or prehypertensive
D) high or fully developed hypertension

Question 50

Numerous body systems deal with the various physiological issues that living organisms face;the internal transport of oxygen,carbon dioxide,nutrients,hormones,and dissolved wastes is the responsibility of the ________ system.

Question 51

Although blood plasma carries many electrolytes,nutrients,and other components,the vast majority of plasma is made of ________.

Question 52

Where is hemoglobin expected to release oxygen?

A) inside an alveolus
B) near red blood cells that are undergoing cellular respiration
C) at the terminal ends of bronchioles
D) near body cells that are undergoing cellular respiration

Question 53

Because of the low pressure and flow rates,the blood in veins may spontaneously clot,as shown below.If the blood clot were to break free it could move to the lungs,causing the life-threatening condition known as ________.

Question 54

The energy required to pump the blood through the systemic circuit is provided by the force generated when the ________ contracts.

Question 55

Terrestrial vertebrates use an enclosed internal lung to respire because it helps to control fluid loss,but fish have no such constraints and exchange their gases using pairs of external ________.

Question 56

The lungs of organism A and organism B have surface areas of 1 cm² and 0.5 cm² per kg body weight,respectively.It would be a reasonable hypothesis that the more metabolically active organism is ________.

Question 57

Human blood appears red because its most abundant cells contain the red pigment ________.

Question 58

Bubbles slowly form in a glass of cold water as it warms because the solubility of dissolved gases is inversely proportional to the ________ of a solution.

Question 59

Why do larger animals depend on an internal transport system (like the circulatory system in mammals)to distribute oxygen when small organisms get along fine without one?

A) Diffusion does not occur in organisms with more than about 300 cells.
B) Large organisms have larger cells and use more oxygen per cell than the cells of small organisms;diffusion alone is unable to supply the extra oxygen needed.
C) Larger animals lose oxygen to the atmosphere as it diffuses through their skin;an internal transport system is needed to replenish these losses.
D) Diffusion delivers oxygen very slowly over distances larger than a typical cell's diameter;transport systems move oxygen close to the cell so that the diffusion distance remains small.

Question 60

The figure below illustrates the inhalation step of gas exchange in humans.

In this figure,which depicts inhalation,the diaphragm and the muscles of the rib cage are ________.

Question 61

Oxygen molecules are symmetrically formed and nonpolar,so they dissolve poorly in water;the concentration of oxygen in the air is much greater.

Question 62

The rate of diffusion declines with increasing distance because the concentration gradient becomes progressively smaller.

Question 63

When red blood cells move through capillaries in single file,the contact area between the two membranes increases and diffusion is improved.

Question 64

Blood pressure increases when blood vessels constrict and their diameters decrease.

Question 65

If an individual has viral bronchitis,it would be accurate to refer to the condition as an upper-respiratory tract infection.

Question 66

Red blood cells are produced in the ________.

Question 67

Since the body is so much larger that the lungs,the volume of blood pumped into the systemic circuit is substantially greater than that pumped into the pulmonary circuit.

Question 68

An irritated pharynx could be caused by sinus drainage.

Question 69

The process of inhalation requires more energy than the process of exhalation.

Question 70

Blood leaving the lungs contains not only oxygen bound to hemoglobin but also oxygen dissolved in the blood plasma and the cytoplasm of the red blood cell.

Question 71

If skin were the gas exchange surface for humans,it would have sufficient surface area to support our need for oxygen.

Question 72

An injury to the atrioventricular node would produce a heartbeat with some type of irregularity in the contractions of the ventricles.

Question 73

A patient with a low platelet count might be easily fatigued but would have a normal risk for bleeding.

Question 74

Lance Armstrong and a significant group of world-class cyclists have been stripped of their medals and banned from international competition for using the synthetic hormone ________ to enhance their performances.

Question 75

The thickening of the arterial walls over time elevates blood pressure and helps move the blood more efficiently throughout the body.

Question 76

Erythropoietin (EPO),which is made by the kidneys,is involved in the production of white blood cells that carry oxygen throughout the body.

Question 77

The movement of the chest during inhalation is the result of the inflated lungs pushing the chest wall outward.