Question 1

Which of the following best describes the primary function of the respiratory system in most terrestrial vertebrates?

Accepted Answer

To facilitate gas exchange by providing a large, moist surface for diffusion of O$_2$ and CO$_2$

Question 2

A patient is diagnosed with emphysema, a disease in which alveolar walls break down. Which of the following physiological consequences is most likely to occur?

Accepted Answer

Decreased elasticity of the lungs, resulting in reduced efficiency of ventilation

Question 3

Which of the following equations correctly represents the relationship between cardiac output ($CO$), heart rate ($HR$), and stroke volume ($SV$)?

Accepted Answer

$CO = HR 	imes SV$

Question 4

Why must gas-exchange surfaces, such as alveoli in mammalian lungs, remain moist?

Accepted Answer

Moisture facilitates the diffusion of O$_2$ and CO$_2$ across the thin epithelial layer

Question 5

Which of the following best explains why small animals like flatworms can rely on diffusion alone for gas exchange?

Accepted Answer

They have a high surface-area-to-volume ratio, allowing efficient diffusion across their body surface

Question 6

During vigorous exercise, arterioles in the skin dilate. What is the physiological significance of this response?

Accepted Answer

It increases blood flow to the skin to help eliminate excess heat

Question 7

Which of the following statements about hemoglobin is correct?

Accepted Answer

Each hemoglobin molecule contains four heme groups, each capable of binding one O$_2$ molecule

Question 8

A person stands up quickly and feels dizzy. Which homeostatic mechanism is most directly responsible for restoring normal blood flow to the brain?

Accepted Answer

Baroreceptors detect the drop in blood pressure and trigger vasoconstriction and increased cardiac output

Question 9

Which of the following best describes the difference between open and closed circulatory systems?

Accepted Answer

Open systems have no distinction between circulating and extracellular fluid, while closed systems keep blood enclosed in vessels

Question 10

Which of the following is the correct sequence of blood flow through the human heart and lungs, starting with deoxygenated blood returning from the body?

Accepted Answer

Right atrium → right ventricle → pulmonary artery → lungs → pulmonary vein → left atrium → left ventricle → aorta

Question 11

Which of the following best explains why high blood pressure (hypertension) is a serious health concern?

Accepted Answer

It puts mechanical stress on artery walls, increasing the risk of heart attack, stroke, and kidney failure

Question 12

Which of the following is a function of the lymphatic system?

Accepted Answer

Draining excess interstitial fluid and returning it to the blood

Question 13

A person with a damaged heart valve is at risk for which of the following complications?

Accepted Answer

Backflow of blood, leading to a heart murmur

Question 14

Which of the following best describes the role of capillaries in the circulatory system?

Accepted Answer

They are thin-walled vessels that allow exchange of gases, nutrients, and wastes between blood and tissues

Question 15

Which of the following statements about the cardiac cycle is correct?

Accepted Answer

The cardiac cycle consists of one complete systole and one complete diastole for both atria and ventricles

Question 16

Which of the following is a direct effect of atherosclerosis in arteries?

Accepted Answer

Accumulation of fatty material beneath the lining of arteries, reducing blood flow

Question 17

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

Accepted Answer

Oxygen concentration is higher in the alveoli than in the blood, so it diffuses down its concentration gradient

Question 18

Which of the following is a correct statement about the pulmonary and systemic circuits in the human circulatory system?

Accepted Answer

The pulmonary circuit carries blood from the right ventricle to the lungs and back to the left atrium

Question 19

A person with chronic obstructive pulmonary disease (COPD) is likely to experience which of the following symptoms?

Accepted Answer

Obstructed airflow and difficulty in gas exchange

Gas Exchange and Circulation (Chapter 42) – Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards