Anatomy and Physiology Hesi A2 Practice Test

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.

Correct Answer: A

Rationale: The correct answer is A. The ulnar nerve supplies sensation to the little finger and half of the ring finger, as well as the corresponding part of the palm. Damage to the ulnar nerve would result in decreased sensation in the hand, specifically in the mentioned areas. Choices B, C, and D are incorrect because the ulnar nerve does not innervate the arm, leg, or foot, respectively. This is why option A is the most appropriate answer based on the nerve's anatomy and distribution of sensory input.

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: 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: Left ventricle. The left ventricle is the largest and strongest chamber of the heart because it is responsible for pumping oxygenated blood to the entire body. It has thick muscular walls to generate enough force to propel blood through the systemic circulation. The right atrium (choice A) receives deoxygenated blood from the body, the right ventricle (choice C) pumps this blood to the lungs for oxygenation, and the left atrium (choice D) receives oxygenated blood from the lungs. None of these chambers have the same pumping workload and muscular thickness as the left ventricle, making it the correct answer.