Anatomy HESI A2 Practice Test

Correct Answer: C

Rationale: The function of the alveoli in the lungs is to exchange gases. Oxygen from the inhaled air diffuses into the bloodstream, while carbon dioxide from the bloodstream diffuses into the alveoli to be exhaled. This exchange process is crucial for maintaining proper oxygen levels in the blood and removing carbon dioxide, a waste product. Option A is incorrect because the alveoli do not absorb oxygen but facilitate its exchange. Option B is incorrect because while the alveoli do remove carbon dioxide, their primary function is gas exchange. Option D is incorrect as the alveoli do not regulate blood pressure but are essential for gas exchange in the respiratory system.

Correct Answer: B

Rationale: The correct answer is B: Cerebrum. The cerebrum, specifically the motor cortex located in the frontal lobe, controls voluntary movement. It sends signals to the muscles via the spinal cord. The cerebellum (A) is responsible for coordination and balance, not voluntary movement. The brainstem (C) controls basic life functions like breathing and heart rate, while the medulla oblongata (D) regulates vital functions such as blood pressure and breathing, not voluntary movement. Therefore, the cerebrum is the correct choice for controlling voluntary movement.

Correct Answer: C

Rationale: The correct answer is C: To store urine. The urinary bladder is a muscular organ that serves as a reservoir for urine produced by the kidneys. It temporarily stores urine until it is ready to be excreted from the body. Filtering blood (A) is the function of the kidneys, storing and concentrating bile (B) is the function of the gallbladder, and absorbing nutrients (D) mostly occurs in the small intestine. Therefore, the main function of the urinary bladder is to store urine before it is eliminated from the body.

Correct Answer: B

Rationale: The primary function of the alveoli in the lungs is to exchange oxygen and carbon dioxide. This process occurs through diffusion, where oxygen moves from the alveoli into the bloodstream, and carbon dioxide moves from the bloodstream into the alveoli to be exhaled. This exchange is essential for oxygenating the blood and removing carbon dioxide, maintaining proper gas exchange in the body. Why the other choices are incorrect: A: Alveoli do play a role in removing carbon dioxide, but their primary function is the exchange of oxygen and carbon dioxide. C: While alveoli do transport oxygen to the bloodstream, they also exchange carbon dioxide, making this choice incomplete. D: Alveoli do not filter blood; their main function is gas exchange in the lungs.

Correct Answer: A

Rationale: The primary function of the liver is to detoxify harmful substances. It metabolizes and neutralizes toxins, drugs, and other harmful compounds. It does this through various enzymatic processes. Producing bile (choice B) is an important function of the liver, but it is not the primary function. Producing insulin (choice C) is a function of the pancreas, not the liver. Storing glycogen (choice D) is a function of the liver, but it is not the primary function.