HESI A2 Anatomy and Physiology Practice Test 2023

Correct Answer: B

Rationale: The correct answer is B: To fight infections. The immune system's primary function is to protect the body from harmful pathogens such as bacteria, viruses, and parasites. It does this by identifying and destroying these invaders to prevent infections and maintain overall health. Choices A, C, and D are incorrect because transporting oxygen is the role of the respiratory system, producing energy is the role of the metabolic system, and regulating body temperature is the role of the thermoregulatory system, not the immune system.

Correct Answer: C

Rationale: The correct answer is C: Regulating body temperature. The nervous system plays a vital role in maintaining homeostasis by controlling body temperature through signals to sweat glands and blood vessels. Choices A, B, and D are incorrect because transporting blood is primarily done by the circulatory system, protecting the body from infection is the role of the immune system, and digesting food is the function of the digestive system.

Correct Answer: B

Rationale: The correct answer is B: To absorb water. The primary role of the large intestine is to absorb water from the undigested food material that passes through it. This ensures that the body maintains proper hydration and regulates the consistency of stool. The other choices are incorrect because: A: The small intestine is primarily responsible for absorbing nutrients, not the large intestine. C: The breakdown of food mainly occurs in the stomach and small intestine, not the large intestine. D: Digestive enzymes are primarily secreted by the pancreas and small intestine, not the large intestine.

Correct Answer: B

Rationale: The correct answer is B: To secrete digestive enzymes. The pancreas secretes enzymes such as amylase, lipase, and proteases that aid in breaking down carbohydrates, fats, and proteins in the small intestine. This supports the digestion and absorption of nutrients. Choices A, C, and D are incorrect because the pancreas does not directly absorb nutrients, produce bile, or store glucose.

Correct Answer: B

Rationale: B-lymphocytes are produced in the red bone marrow. This is because red bone marrow is the primary site of hematopoiesis in adults, where all blood cells, including B-lymphocytes, are produced. The thymus is responsible for T-lymphocyte maturation, not production. Lymph nodes and spleen are sites where B-lymphocytes can mature and become activated but not produced.