Question 1

Which of the following best explains why oxygen moves from the alveoli into the blood in the lungs?

Accepted Answer

Oxygen moves from an area of higher partial pressure in the alveoli to a lower partial pressure in the blood.

Question 2

During vigorous exercise, which of the following changes would you expect in the blood near active muscles?

Accepted Answer

Decreased pH and decreased hemoglobin saturation percentage.

Question 3

Most carbon dioxide ($$\mathrm{CO_2$}) in $$the blood is transported in which of the following forms?

Accepted Answer

As bicarbonate ions ($$\mathrm{$$HCO_3$$^-}) in $$plasma.

Question 4

A patient is experiencing hyperventilation. What is the most likely effect on blood pH and why?

Accepted Answer

Blood pH increases because more $$\mathrm{CO_2$} is $$exhaled, reducing carbonic acid.

Question 5

Which equation correctly represents the reversible reaction for the conversion of carbon dioxide to bicarbonate in the blood?

Accepted Answer

$$\mathrm{CO_2$ + H_2O \rightleftharpoons H_2CO_3 \rightleftharpoons H^+ + $$HCO_3$$^-}$$

Question 6

If the partial pressure of oxygen ($$P_{O_2$}) in $$the alveoli is 100 mmHg and in the blood entering the lungs is 40 mmHg, what is the direction of oxygen movement?

Accepted Answer

Oxygen moves from the alveoli into the blood.

Question 7

Which of the following best describes the role of the medulla in respiration?

Accepted Answer

It detects changes in blood pH and $$\mathrm{CO_2$}$$ levels to regulate breathing rate.

Question 8

A decrease in blood pH will have what effect on hemoglobin's affinity for oxygen?

Accepted Answer

Decrease hemoglobin's affinity for oxygen.

Question 9

Which of the following scenarios would most likely cause an increase in breathing rate?

Accepted Answer

Increased $$\mathrm{CO_2$}$$ levels and decreased blood pH.

Question 10

A person at high altitude is exposed to lower atmospheric oxygen. Which physiological response would help maintain oxygen delivery to tissues?

Accepted Answer

Increased breathing rate to raise alveolar $$P_{O_2$}.$$

Question 11

Which of the following best explains why hemoglobin releases more oxygen in actively metabolizing tissues?

Accepted Answer

Active tissues have higher $$\mathrm{CO_2$}$$ and lower pH, which decreases hemoglobin's affinity for oxygen.

Question 12

Which of the following is NOT a form in which carbon dioxide is transported in the blood?

Accepted Answer

Bound to oxygen as oxyhemoglobin.

Question 13

If a person holds their breath, what immediate change occurs in their blood chemistry?

Accepted Answer

Increase in $$\mathrm{CO_2$}$$ and decrease in pH.

Question 14

Which of the following best describes hemoglobin saturation percentage?

Accepted Answer

The percentage of hemoglobin binding sites occupied by oxygen.

Question 15

A person with chronic obstructive pulmonary disease (COPD) has impaired gas exchange in the lungs. Which of the following is a likely consequence?

Accepted Answer

Increased $$\mathrm{CO_2$}$$ and decreased oxygen in the blood.

Question 16

Which of the following would most likely occur if the partial pressure of carbon dioxide in the blood increases?

Accepted Answer

The medulla increases the breathing rate.

Question 17

Which of the following best describes the Bohr effect?

Accepted Answer

Hemoglobin releases more oxygen at lower pH.

Question 18

If a person is exposed to carbon monoxide ($$\mathrm{CO}$$), which binds to hemoglobin more strongly than oxygen, what is the most likely effect?

Accepted Answer

Decreased hemoglobin saturation percentage with oxygen.

Question 19

Which of the following is the correct sequence for the movement of oxygen from the atmosphere to the tissues?

Accepted Answer

Atmosphere $$\rightarrow$$ alveoli $$\rightarrow$$ blood $$\rightarrow$$ tissues

Question 20

A climber at high altitude hyperventilates. What is the most likely effect on their blood chemistry?

Accepted Answer

Decrease in $$\mathrm{CO_2$}$$ and increase in blood pH.

Respiration and Gas Exchange: Mechanisms and Regulation

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