Question 1

Which of the following best describes the difference between pulmonary ventilation and cellular respiration?

Accepted Answer

Pulmonary ventilation is the movement of air into and out of the lungs, while cellular respiration is the use of oxygen to produce ATP in mitochondria.

Question 2

According to Boyle’s Law, what happens to the pressure inside the thoracic cavity when its volume increases during inspiration?

Accepted Answer

The pressure decreases, allowing air to flow into the lungs.

Question 3

Which muscle is primarily responsible for increasing the volume of the thoracic cavity during inspiration?

Accepted Answer

Diaphragm

Question 4

A patient at high altitude finds it harder to breathe. Which of the following best explains why?

Accepted Answer

Atmospheric pressure is lower, so a greater increase in chest volume is required to create a pressure differential for air to enter the lungs.

Question 5

Which of the following equations correctly represents the calculation of vital capacity (VC)?

Accepted Answer

$$VC = TV + IRV + ERV$$

Question 6

During forced expiration, which muscle group contracts to push the diaphragm upward?

Accepted Answer

Abdominal muscles

Question 7

What is the main form in which carbon dioxide is transported in the blood?

Accepted Answer

As bicarbonate ion ($$HCO_3$$^-$$)

Question 8

Which of the following best describes the action of antagonistic muscle groups during breathing?

Accepted Answer

One muscle group contracts to cause inspiration, while the opposing group contracts to cause expiration.

Question 9

A patient with a punctured chest wall develops a pneumothorax. What is the immediate consequence for the affected lung?

Accepted Answer

The lung collapses because intrapleural pressure equals atmospheric pressure.

Question 10

Which of the following best explains why hyperventilation can lead to alkalosis?

Accepted Answer

Excessive exhalation of $$CO_2$$ reduces carbonic acid in the blood, raising blood pH.

Question 11

Which brain region is primarily responsible for setting the basic rhythm of breathing?

Accepted Answer

Medulla oblongata

Question 12

During external respiration, which direction does oxygen move?

Accepted Answer

From alveoli into pulmonary capillaries

Question 13

Which of the following is a nonrespiratory air movement and its correct mechanism?

Accepted Answer

Cough: Forcing air superiorly from lungs against a closed glottis

Question 14

Which of the following best describes the role of chemoreceptors in the control of respiration?

Accepted Answer

They detect changes in blood pH and $$CO_2$$ levels, sending signals to the medulla to adjust breathing rate.

Question 15

A person holds their breath voluntarily. What ultimately forces them to resume breathing?

Accepted Answer

Rising $$CO_2$$ levels and falling blood pH override voluntary control.

Question 16

Which of the following best explains why residual volume is important for lung function?

Accepted Answer

It prevents lung collapse by keeping alveoli partially inflated between breaths.

Question 17

Which of the following equations represents the conversion of carbon dioxide to bicarbonate ion in red blood cells?

Accepted Answer

$$CO_2 + H_2O$$ \rightarrow H_2CO_3 \rightarrow H^+ + $$HCO_3$$^-$$

Question 18

Which of the following is the smallest respiratory volume?

Accepted Answer

Tidal volume (TV)

Question 19

Which of the following best describes the movement of the rib cage during inspiration?

Accepted Answer

The external intercostal muscles contract, lifting the rib cage upward and outward.

Question 20

Which of the following best explains why cyanosis occurs?

Accepted Answer

Inadequate oxygenation of the blood leads to a bluish cast to the skin and mucous membranes.

Respiratory Physiology: Mechanisms and Control of Breathing

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