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 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: Ribosome. Ribosomes are responsible for protein synthesis as they are the cellular structures where translation of mRNA into proteins occurs. Ribosomes read the genetic code carried by mRNA and assemble amino acids into proteins. The other choices are incorrect because the nucleus houses the DNA and controls cell activities, the endoplasmic reticulum is involved in protein processing and transport, and the Golgi apparatus modifies and packages proteins for secretion. However, only ribosomes are directly responsible for protein synthesis.

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.