AP Biology - Respiratory Physiology

1

Mountain climbing at a high altitude can have an affect on one's ability to breath efficiently. At high altitudes, atmospheric pressure can decrease dramatically and result in a lower drive for oxygen into the lungs. The body will try to compensate by increasing the rate of respiration.

How does hyperventilating change the blood chemistry in the human body?

Hyperventilating will release more $CO_{2}$ and result in an increase in the blood's pH

Hyperventilating will release more $CO_{2}$ and result in a drop in the blood's pH

Hyperventilating will retain more $CO_{2}$ and result in an increase in the blood's pH

Hyperventilating will retain more $CO_{2}$ and result in a decrease in the blood's pH

Hyperventilating will not affect the blood's pH.

Explanation

$CO_{2} + H_{2} 0 \leftrightarrow HCO_{3}^{-} + H^{+}$

Hyperventilation will result in the expiration of more $CO_{2}$ . It can be deduced that a greater amount of expired $CO_{2}$ will cause the above equation to shift to the left. The shifting of the equation to the left will further promote the conversion of $H^{+}$ and $HCO_{3}^{-}$ to $CO_{2}$ and $H_{2}0$ . Since the body uses $HCO_{3}^{-}$ as a buffer, there will be a greater quantity of the bicarbonate in the body than $H^{+}$ . When the equation shifts to the left, the $H^{+}$ will deplete at a faster rate and result in a higher $HCO_{3}^{-}$ to $H^{+}$ ratio. A higher $HCO_{3}^{-}$ to $H^{+}$ ratio will cause the body's blood to become more basic (increase in pH); therefore, hyperventilation increases blood bascicity.

2

Mountain climbing at a high altitude can have an affect on one's ability to breath efficiently. At high altitudes, atmospheric pressure can decrease dramatically and result in a lower drive for oxygen into the lungs. The body will try to compensate by increasing the rate of respiration.

How does hyperventilating change the blood chemistry in the human body?

Hyperventilating will release more $CO_{2}$ and result in an increase in the blood's pH

Hyperventilating will release more $CO_{2}$ and result in a drop in the blood's pH

Hyperventilating will retain more $CO_{2}$ and result in an increase in the blood's pH

Hyperventilating will retain more $CO_{2}$ and result in a decrease in the blood's pH

Hyperventilating will not affect the blood's pH.

Explanation

$CO_{2} + H_{2} 0 \leftrightarrow HCO_{3}^{-} + H^{+}$

Hyperventilation will result in the expiration of more $CO_{2}$ . It can be deduced that a greater amount of expired $CO_{2}$ will cause the above equation to shift to the left. The shifting of the equation to the left will further promote the conversion of $H^{+}$ and $HCO_{3}^{-}$ to $CO_{2}$ and $H_{2}0$ . Since the body uses $HCO_{3}^{-}$ as a buffer, there will be a greater quantity of the bicarbonate in the body than $H^{+}$ . When the equation shifts to the left, the $H^{+}$ will deplete at a faster rate and result in a higher $HCO_{3}^{-}$ to $H^{+}$ ratio. A higher $HCO_{3}^{-}$ to $H^{+}$ ratio will cause the body's blood to become more basic (increase in pH); therefore, hyperventilation increases blood bascicity.

3

To initiate inhalation, the diaphragm contracts, making the pressure inside the lungs __________.

lower than the pressure outside the body

higher than the pressure outside the body

the same as the pressure outside the body

zero

None of these

Explanation

Inhalation happens by making the pressure in the lungs lower relative to the pressure outside the body. When the diaphragm contracts, it increases the volume of the thoracic cavity. By Boyle's law, there is an inverse relationship between pressure and volume of a gas. Thus the pressure of the thoracic cavity decreases and since air will flow from high to low pressure, this pulls air into the lungs during inhalation.

4

To initiate inhalation, the diaphragm contracts, making the pressure inside the lungs __________.

lower than the pressure outside the body

higher than the pressure outside the body

the same as the pressure outside the body

zero

None of these

Explanation

Inhalation happens by making the pressure in the lungs lower relative to the pressure outside the body. When the diaphragm contracts, it increases the volume of the thoracic cavity. By Boyle's law, there is an inverse relationship between pressure and volume of a gas. Thus the pressure of the thoracic cavity decreases and since air will flow from high to low pressure, this pulls air into the lungs during inhalation.

5

Terrestrial animals must combat the drying out of respiratory surfaces due to evaporation. What is one strategy they use?

Folding the respiratory surface into the body

Increased perspiration of cells on respiratory surface

Excretion of fluids from walls of lungs

Having very low respiratory rates

Increased metabolism

Explanation

By folding the respiratory surface into the body, terrestrial animals increase the humidity of the environment of the respiratory surface, which will minimize evaporation and maintain moisture. Note that water loss via evaporation and perspiration accounts for the majority of water loss in terrestrial mammals.

6

Terrestrial animals must combat the drying out of respiratory surfaces due to evaporation. What is one strategy they use?

Folding the respiratory surface into the body

Increased perspiration of cells on respiratory surface

Excretion of fluids from walls of lungs

Having very low respiratory rates

Increased metabolism

Explanation

By folding the respiratory surface into the body, terrestrial animals increase the humidity of the environment of the respiratory surface, which will minimize evaporation and maintain moisture. Note that water loss via evaporation and perspiration accounts for the majority of water loss in terrestrial mammals.

7

Which of the following answers lists the correct order of respiratory structures that air moves through as it is drawn into the lungs?

Trachea, bronchi, bronchioles, alveoli

Trachea, bronchioles, bronchi, alveoli

Bronchi, bronchioles, alveoli, trachea

Alveoli, trachea, bronchi, bronchioles

Explanation

Air enters the body of most terrestrial vertebrates through the nose or the mouth; the air then passes through the trachea to narrower tubes called the bronchi, to still narrower tubes called the bronchioles. The bronchioles "dead end" into structures called alveoli, which is where gas exchange of oxygen and carbon dioxide takes place with the blood in adjacent capillaries.

8

Which of the following answers lists the correct order of respiratory structures that air moves through as it is drawn into the lungs?

Trachea, bronchi, bronchioles, alveoli

Trachea, bronchioles, bronchi, alveoli

Bronchi, bronchioles, alveoli, trachea

Alveoli, trachea, bronchi, bronchioles

Explanation

Air enters the body of most terrestrial vertebrates through the nose or the mouth; the air then passes through the trachea to narrower tubes called the bronchi, to still narrower tubes called the bronchioles. The bronchioles "dead end" into structures called alveoli, which is where gas exchange of oxygen and carbon dioxide takes place with the blood in adjacent capillaries.

9

Which of the following structures is not found within the lungs?

Trachea

Bronchi

Bronchioles

Alveoli

Explanation

The lungs contain the bronchioles, the alveoli, and part of the bronchi. The trachea carries inhaled air into the bronchi, but it is not actually enclosed by the bronchi— the lungs only enclose structures that arise after the bronchi branch away from the trachea.

10

What causes air to enter human lungs?

The contraction of the diaphragm increases the volume of the lungs, decreasing the pressure relative to the air outside the body.

Air diffuses into the lungs due to the decreased content relative to the air outside our body.

Smooth muscle in the trachea guides the flow of air into the lungs.

Cillia in the trachea guide the flow of air into the lungs.

The decreased concentration of in the lungs decreases the density of that air, and denser air outside the body "sinks" into the lungs.

Explanation

Increasing the volume of a container (in this case, the lungs) while keeping the contents (air molecules) the same will decrease the pressure. If no barrier is present (as when holding your breath), pressure will tend to equalize between areas of differing pressure. In order to equalize the pressure, air molecules from outside the body rush into the expanded lungs. The concentration of oxygen does not impact inhalation, and cilia are not used to inhale.

Respiratory Physiology

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