Question 1

Which of the following best describes the primary function of the respiratory system?

Accepted Answer

To facilitate the diffusion of gases (O$$_2$$ and CO$$_2) $$between the atmosphere and blood.

Question 2

Gas exchange in the lungs occurs across a structure that is how many cell layers thick?

Accepted Answer

Two living cell layers thick.

Question 3

Which muscles are primarily responsible for the physical effort required during breathing?

Accepted Answer

Diaphragm and intercostal muscles.

Question 4

What is the main reason you cannot hold your breath indefinitely, even if you try?

Accepted Answer

Powerful feedback control mechanisms maintain homeostasis of blood O$$_2$$ and CO$$_2.$$

Question 5

Why are red blood cells essential for transporting O$$_2$$ from the lungs to all living cells?

Accepted Answer

Blood plasma alone could not carry enough O$$_2$$ for survival.

Question 6

Which of the following statements about the structure of the respiratory membrane is correct?

Accepted Answer

It must be kept moist, clean, and free of microorganisms to function properly.

Question 7

During exercise, why does your breathing rate increase automatically?

Accepted Answer

Feedback control mechanisms detect changes in blood CO$$_2$$ and O$$_2$$ levels.

Question 8

Which of the following best explains why the respiratory membrane must be thin?

Accepted Answer

To allow efficient diffusion of O$$_2$$ and CO$$_2.$$

Question 9

If the respiratory membrane becomes thickened due to disease, what is the most likely consequence?

Accepted Answer

Reduced efficiency of gas exchange.

Question 10

Which of the following equations best represents the reversible reaction for oxygen transport by hemoglobin?

Accepted Answer

$$\mathrm{Hb} + \mathrm{O}_2 \rightleftharpoons \mathrm{HbO}_2$$

Question 11

A patient with a genetic disorder has red blood cells that cannot bind oxygen efficiently. What is the most likely outcome?

Accepted Answer

Tissues will receive less oxygen, leading to cellular hypoxia.

Question 12

Which of the following best describes the role of the diaphragm in breathing?

Accepted Answer

It contracts to increase thoracic volume during inspiration.

Question 13

Which feedback mechanism is most sensitive to changes in arterial CO$$_2$$ levels?

Accepted Answer

Central chemoreceptors in the medulla oblongata.

Question 14

If the respiratory membrane is not kept clean and moist, what is the most likely effect?

Accepted Answer

Impaired gas exchange and increased risk of infection.

Question 15

Which of the following is NOT a function of the respiratory system?

Accepted Answer

Production of digestive enzymes.

Respiratory System: Structure, Function, and Regulation

Study Guide - Practice Questions