Question 1

Air entering the lungs has a
A)higher concentration of carbon dioxide than air in an alveolus.
B)higher concentration of both carbon dioxide and oxygen than in an alveolus.
C)higher concentration of oxygen and a lower concentration of carbon dioxide than in an alveolus.
D)lower concentration of oxygen and a concentration of carbon dioxide equal to that in an alveolus.

Accepted Answer

Air entering the lungs has a higher concentration of oxygen and a lower concentration of carbon dioxide than in an alveolus. During inhalation, air travels down the bronchial tubes and reaches the alveoli. The alveoli are surrounded by capillaries, which exchange oxygen and carbon dioxide with the blood. The concentration of oxygen is higher in the air entering the lungs than in the alveoli because the air has not yet been depleted by gas exchange with the blood. Similarly, the concentration of carbon dioxide is lower in the air entering the lungs because it has not yet picked up the carbon dioxide exhaled from the body.

Question 2

The breaking open of alveoli in people with emphysema decreases their rate of gas exchange because
A)the distance between the air they breathe in and the blood is decreased.
B)there is less pressure in the lungs to force the oxygen to dissolve in the blood.
C)the concentration of oxygen in the lungs becomes much greater than that in the blood.
D)their lungs have less surface area available for diffusion.

Accepted Answer

Emphysema causes the destruction of alveoli, which reduces the surface area available for gas exchange. This means there are fewer functional alveoli for gases to diffuse across, resulting in a decrease in the rate of gas exchange. The other options (A, B, and C) are not accurate explanations for the decreased gas exchange in people with emphysema.

Question 3

In cystic fibrosis, parts of the respiratory tract can be clogged with mucus and inhibit gas exchange. The areas of the respiratory tract where gases are directly exchanged are the
A)alveoli.
B)bronchi.
C)diaphragm.
D)trachea.

Accepted Answer

The alveoli are the small air sacs in the lungs where oxygen and carbon dioxide are exchanged during respiration. In cystic fibrosis, excessive mucus production can clog the airways and impair gas exchange in the alveoli, leading to respiratory difficulties. The other options (bronchi, diaphragm, and trachea) play important roles in respiration but are not directly involved in gas exchange.

Question 4

Too much salt in the diet can increase blood pressure because
A)greater solute levels cause interstitial fluid and blood plasma volume to increase with water.
B)the blood volume loses water and becomes too thick.
C)salt forces the blood vessels to constrict.
D)interstitial fluid and blood plasma are more concentrated with salt and make the heart beat quicker.

Accepted Answer

Excess salt in the diet leads to greater solute levels, causing the body to retain water to balance the concentration, which increases blood volume and subsequently raises blood pressure.

Question 5

The image below illustrates how a continual diet of trans fats can lead to hardening of the arteries, which is a condition also known as 
A)systemic thrombosis.
B)atherosclerosis.
C)pulmonary thrombosis.
D)circulatory fibromatosis.

Accepted Answer

A continual diet of trans fats can lead to the buildup of plaque in the arteries, which can cause the arteries to become narrower and less flexible. This condition is known as atherosclerosis, which can lead to serious health problems such as heart attacks, strokes, and peripheral artery disease.

Question 6

Another name for the "pacemaker" is the
A)atrioventricular (AV) node.
B)sino atrial (SA) node.
C)atrium.
D)ventrical.

Accepted Answer

The sino atrial (SA) node is also known as the pacemaker of the heart. It initiates and regulates the electrical impulses that cause the heart to beat. The atrioventricular (AV) node is another part of the heart's electrical system, but it helps to relay the impulses from the SA node to the ventricles. The atrium and ventricles are chambers of the heart, but they are not synonymous with the pacemaker.

Question 7

When we inhale, air moves in through the mouth or nose and next moves into the
A)bronchi.
B)alveoli.
C)lungs.
D)pharynx.

Accepted Answer

When we inhale, air first moves through the mouth or nose and then into the pharynx before reaching the bronchi, alveoli, and lungs.

Question 8

Which of the following statements about gas concentrations in air and water is true?
A)Carbon dioxide is not found in water.
B)Carbon dioxide occurs in similar concentrations in air and water.
C)Oxygen occurs in similar concentrations in air and water.
D)Oxygen occurs in higher concentrations in air than in water.

Accepted Answer

Oxygen occurs in higher concentrations in air than in water. While carbon dioxide occurs in higher concentrations in water than in air. Oxygen and carbon dioxide exist in different concentrations in air and water.

Question 9

Which of the following best describes the journey of an oxygen molecule in a lung?
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.

Accepted Answer

An oxygen molecule enters the lung through a bronchiole, then moves into an alveolus (air sac) where it diffuses across the alveolar membrane and into a capillary. The oxygen molecule then binds to a red blood cell, specifically to the hemoglobin protein inside the red blood cell, which then transports the oxygen molecule to the body's tissues.

Question 10

For a human to inhale, the rib muscles and diaphragm must
A)contract, decreasing pressure inside the lungs.
B)relax, increasing pressure inside the lungs.
C)contract, increasing pressure inside the lungs.
D)relax, decreasing pressure inside the lungs.

Accepted Answer

When the rib muscles and diaphragm contract, the volume inside the lungs increases, which leads to a decrease in pressure. This creates a pressure gradient that allows air to flow into the lungs, which is inhalation. Therefore, A is the correct choice as it describes the process of inhaling.

Question 11

Which of the following statements about the size of an organism's gas exchange surface is true?
A)Organisms with small demands generally still have large gas exchange surfaces.
B)Extra gill surface area in a fish would help lower the drag forces in water.
C)The surface area of a gas exchange surface is sized to match the needs of the organism.
D)The lungs of active mammals have smaller gas exchange surfaces than the lungs of less active mammals.

Accepted Answer

Gas exchange surfaces need to match the needs of the organism, whether big or small. Animals with high metabolic rates or high oxygen demands typically have larger gas exchange surfaces compared to those with lower demands.

Question 12

Air enters the lungs through a pair of tubes known as
A)bronchi.
B)alveoli.
C)bronchioles.
D)pharynx.

Accepted Answer

The bronchi are the two main branches of the trachea that carry air into the lungs. The alveoli are small air sacs within the lungs where gas exchange occurs. The bronchioles are smaller branches of the bronchi that lead to the alveoli. The pharynx is a muscular tube that connects the nose and mouth to the esophagus and trachea.

Question 13

Which of the following would have the smallest diameter?
A)the pharynx
B)the trachea
C)the bronchi
D)the bronchioles

Accepted Answer

The bronchioles have the smallest diameter among the given structures. As air travels down the respiratory pathway, it goes from larger structures to smaller ones, with the bronchioles being the final branches that lead to the alveoli.

Question 14

What tube connects the pharynx to the bronchi?
A)the trachea
B)the alveoli
C)the bronchioles
D)the tracheoles

Accepted Answer

The trachea, also known as the windpipe, connects the pharynx (throat) to the bronchi, which lead to the lungs.

Question 15

In the figure below, the arrow is pointing to the 
A)bronchus.
B)trachea.
C)diaphragm.
D)larynx.

Accepted Answer

The answer of In the figure below, the arrow is...

Question 16

Which of the following describes the journey of a molecule of oxygen from the pharynx to an alveolus?
A)pharynx to trachea to bronchus to bronchiole to alveolus
B)pharynx to trachea to bronchiole to bronchus to alveolus
C)pharynx to bronchiole to bronchus to trachea to alveolus
D)pharynx to bronchus to bronchiole to trachea to alveolus

Accepted Answer

The correct order for the journey of a molecule of oxygen is from the pharynx to the trachea to the bronchus to the bronchiole to the alveolus. This matches option A.

Question 17

The tiniest bronchiole extensions open into the
A)trachea.
B)bronchi.
C)alveoli.
D)pharynx.

Accepted Answer

The smallest bronchiole extensions lead into the alveoli, the tiny air sacs in the lungs where gas exchange takes place between the air and blood. The trachea, bronchi, and pharynx are all larger air passages that lead to and from the lungs. Therefore, option A, B, and D are not correct.

Question 18

Once oxygen has entered the blood stream, its ultimate destination is the
A)alveoli.
B)lungs.
C)cells.
D)mitochondria.

Accepted Answer

The answer of Once oxygen has entered the blood stream,...

Question 19

In what way, if any, is the circulatory system of humans important to the process of gas exchange?
A)It has no importance to gas exchange.
B)It allows air to be taken into the lungs.
C)It increases the area available for gas exchange.
D)It carries oxygen to cells that are not in direct contact with air.

Accepted Answer

The circulatory system carries oxygen from the lungs to the body's cells that are not in direct contact with air (such as those in muscles and organs). Without the circulatory system, oxygen would not be able to reach all parts of the body in sufficient amounts for proper functioning. Therefore, it is important to the overall process of gas exchange in the body.

Question 20

In human lungs, gases are exchanged in tiny sacs called
A)gills.
B)tracheoles.
C)alveoli.
D)spongy parenchyma.

Accepted Answer

The tiny sacs in human lungs where gases are exchanged are called alveoli.

Quiz 28: Circulation and Gas Exchange

Air entering the lungs has a

The breaking open of alveoli in people with emphysema decreases their rate of gas exchange because

In cystic fibrosis, parts of the respiratory tract can be clogged with mucus and inhibit gas exchange. The areas of the respiratory tract where gases are directly exchanged are the

Too much salt in the diet can increase blood pressure because

The image below illustrates how a continual diet of trans fats can lead to hardening of the arteries, which is a condition also known as

Another name for the "pacemaker" is the

When we inhale, air moves in through the mouth or nose and next moves into the

Which of the following statements about gas concentrations in air and water is true?

Which of the following best describes the journey of an oxygen molecule in a lung?

For a human to inhale, the rib muscles and diaphragm must

Which of the following statements about the size of an organism's gas exchange surface is true?

Air enters the lungs through a pair of tubes known as

Which of the following would have the smallest diameter?

What tube connects the pharynx to the bronchi?

In the figure below, the arrow is pointing to the

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

The tiniest bronchiole extensions open into the

Once oxygen has entered the blood stream, its ultimate destination is the

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

In human lungs, gases are exchanged in tiny sacs called