Anatomy and Physiology Hesi A2 Practice Test

Correct Answer: B

Rationale: The correct answer is B: Spinal cord. The spinal cord is part of the peripheral nervous system, not the central nervous system. The central nervous system consists of the brain and spinal cord, while the peripheral nervous system includes nerves outside of the brain and spinal cord. The retina (A) is part of the central nervous system as it is an extension of the brain, responsible for processing visual information. The brain (C) is obviously part of the central nervous system as the main control center of the body. The heart (D) is not part of the central nervous system; it is part of the cardiovascular system.

Correct Answer: A

Rationale: The correct answer is A: To filter blood and remove old red blood cells. The spleen acts as a blood filter, removing old or damaged red blood cells and recycling their components. This process helps to maintain a healthy balance of red blood cells in the body. The spleen also plays a role in immune function by trapping and removing pathogens from the blood. It does not produce white blood cells (Choice B), store lymphocytes (Choice C), or produce antibodies (Choice D). These functions are typically carried out by other organs in the immune system, such as the bone marrow, lymph nodes, and lymphoid tissues.

Correct Answer: B

Rationale: The correct answer is B: To absorb nutrients. The small intestine is responsible for absorbing nutrients from digested food into the bloodstream for distribution to the rest of the body. This process involves the absorption of proteins, carbohydrates, fats, vitamins, and minerals. The small intestine does not primarily break down food (A), as this is mainly done in the stomach. While the small intestine does secrete digestive enzymes (C), its primary function is absorption. Lastly, the small intestine does not store glucose (D), as glucose is stored in the liver and muscles.

Correct Answer: B

Rationale: The correct answer is B: Nucleus. The nucleus contains the genetic material in the form of DNA, which carries the instructions for the cell's functions. The DNA is organized into chromosomes within the nucleus. Ribosomes (A) are involved in protein synthesis but do not contain genetic material. Mitochondria (C) have their own DNA but do not house the majority of the cell's genetic material. Endoplasmic reticulum (D) is involved in protein synthesis and lipid metabolism but does not contain genetic material. The nucleus is the control center of the cell, housing the genetic information essential for cell function and replication.

Correct Answer: B

Rationale: The correct answer is B: To protect the body from infections. The immune system's main function is to defend the body against pathogens such as bacteria, viruses, and other harmful microorganisms. It does this by recognizing and attacking these invaders to prevent infections and maintain overall health. Choice A is incorrect as the immune system does not primarily produce hormones. Choice C is incorrect as waste removal is mainly carried out by the excretory system. Choice D is incorrect as regulating body temperature is primarily controlled by the thermoregulatory system, not the immune system.