Anatomy and Physiology Hesi A2 Practice Test

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.

Correct Answer: B

Rationale: The correct answer is B: Mitochondria. Mitochondria are known as the powerhouse of the cell because they are responsible for producing energy in the form of ATP through cellular respiration. They contain enzymes necessary for the production of ATP, which is the main energy currency of the cell. The other choices are incorrect because: A: Nucleus - Responsible for controlling cell activities and storing genetic material. C: Ribosome - Responsible for protein synthesis, not energy production. D: Golgi apparatus - Responsible for processing and packaging proteins for secretion, not energy production.

Correct Answer: B

Rationale: The correct answer is B: Medulla oblongata. The medulla oblongata is located in the brainstem and is responsible for controlling vital functions such as breathing and heart rate. It contains the respiratory center that regulates breathing and the cardiac center that controls heart rate. The cerebrum (A) is involved in higher brain functions such as thinking and voluntary movements, not in controlling basic bodily functions. The cerebellum (C) is responsible for coordination and balance, not for regulating breathing or heart rate. The hypothalamus (D) plays a role in regulating body temperature, hunger, and thirst, but not specifically in controlling breathing and heart rate.

Correct Answer: B

Rationale: The correct answer is B: Erythropoiesis. Erythropoiesis is the process of producing red blood cells. This process occurs in the bone marrow and is regulated by the hormone erythropoietin. Thrombopoiesis (A) is the production of platelets, not red blood cells. Hematopoiesis (C) is the general process of blood cell formation, including red blood cells, white blood cells, and platelets. Phagocytosis (D) is the process by which cells engulf and digest particles, not related to red blood cell production. Therefore, the correct answer is B as it specifically relates to the production of red blood cells.

Correct Answer: B

Rationale: The correct answer is B: To protect against pathogens. The skin acts as a physical barrier that prevents harmful pathogens from entering the body. It also contains specialized immune cells that help to fight off infections. Vitamin D production (choice A) primarily occurs in the skin but is not the main function of skin protection. Storing nutrients (choice C) is not a primary function of the skin. While the skin does play a role in thermoregulation (choice D), its main function in protecting the body is to defend against pathogens.