what is the primary function of the alveoli in the lungs

HESI A2

Anatomy HESI A2 Practice Test

1. What is the primary function of the alveoli in the lungs?

A. Removing carbon dioxide from the blood
B. Exchanging oxygen and carbon dioxide
C. Transporting oxygen to the bloodstream
D. Filtering blood

Correct answer: B

Rationale: The primary function of the alveoli in the lungs is to exchange oxygen and carbon dioxide. The alveoli are tiny air sacs in the lungs responsible for this gas exchange during breathing. Oxygen diffuses from the inhaled air into the blood in the capillaries surrounding the alveoli, while carbon dioxide diffuses from the blood into the alveoli to be exhaled out of the body. Choice A is incorrect because the alveoli primarily facilitate the exchange of gases, not just the removal of carbon dioxide. Choice C is incorrect as the alveoli do not transport oxygen to the bloodstream but rather facilitate the exchange of gases. Choice D is incorrect as the alveoli are not involved in filtering blood but in gas exchange to ensure proper oxygenation and removal of carbon dioxide in the respiratory process.

2. What is the primary function of the cardiovascular system?

A. To transport oxygen and nutrients
B. To remove waste products
C. To regulate body temperature
D. To fight infections

Correct answer: A

Rationale: The correct answer is A: "To transport oxygen and nutrients." The primary function of the cardiovascular system is to transport oxygen, nutrients, and hormones to cells throughout the body and remove waste products. This system plays a crucial role in maintaining homeostasis by delivering essential substances to tissues and organs while eliminating metabolic waste. Choices B, C, and D are incorrect because although the cardiovascular system indirectly helps in removing waste products through circulation, its primary function is focused on transporting essential substances and not on regulating body temperature or fighting infections.

3. What is the main function of the respiratory system?

A. To transport nutrients
B. To regulate body temperature
C. To absorb oxygen and remove carbon dioxide
D. To produce energy

Correct answer: C

Rationale: The main function of the respiratory system is to absorb oxygen from the air into the bloodstream and remove carbon dioxide from the body. Oxygen is essential for cellular respiration, the process through which cells generate energy. Carbon dioxide is a waste product expelled during this process. Choice A, 'To transport nutrients,' is incorrect as the respiratory system is not primarily responsible for transporting nutrients. Choice B, 'To regulate body temperature,' is incorrect as the respiratory system's main role is not temperature regulation. Choice D, 'To produce energy,' is incorrect because while oxygen obtained through respiration is used in the energy production process, the respiratory system itself does not directly produce energy.

4. Which structure in the kidney filters blood?

A. Nephron
B. Glomerulus
C. Bowman's capsule
D. Loop of Henle

Correct answer: B

Rationale: The correct answer is the Glomerulus. The glomerulus is a network of tiny blood vessels located within the Bowman's capsule. It acts as the initial filtering component in the nephron, filtering blood and allowing waste products and excess substances to pass through to form urine. Choice A, Nephron, is incorrect as the nephron is the structural and functional unit of the kidney composed of several parts, including the glomerulus. Choice C, Bowman's capsule, is where the glomerulus is located, but it is not the structure responsible for filtering blood. Choice D, Loop of Henle, plays a role in reabsorption of water and electrolytes but is not the primary structure for blood filtration in the kidney.

5. What is the function of the gallbladder?

A. To produce bile
B. To store and concentrate bile
C. To detoxify harmful substances
D. To break down fats

Correct answer: B

Rationale: The correct answer is B: To store and concentrate bile. The gallbladder's primary function is to store and concentrate bile, which is produced by the liver. Bile is released into the small intestine to aid in the digestion and absorption of fats. It helps in emulsifying fats and facilitating their breakdown by enzymes for better absorption. Choices A, C, and D are incorrect because the gallbladder does not produce bile (it is produced by the liver), detoxify harmful substances, or directly break down fats. Its main role is to store and concentrate bile before releasing it into the small intestine.