Anatomy HESI A2

Correct Answer: D

Rationale: The correct answer is D: Activating vitamin D. Parathyroid hormone regulates calcium levels in the body by stimulating the activation of vitamin D, which helps in calcium absorption from the intestines. This process is crucial for maintaining proper bone health and muscle function. Choices A, B, and C are incorrect because parathyroid hormone does not directly affect energy levels, cell reproduction, or metabolism.

Correct Answer: B

Rationale: The correct answer is B: Iodine. Iodine is essential for the production of thyroid hormones, which are crucial for regulating metabolism and growth. Without enough iodine, the thyroid gland cannot function properly, leading to conditions like hypothyroidism or goiter. A: Manganese does not directly support thyroid function. C: Phosphorus is important for bone health and energy metabolism but not specifically for thyroid function. D: Zinc is involved in various physiological processes, but it is not as critical for thyroid function as iodine. In summary, iodine is the correct answer because it is specifically required for the synthesis of thyroid hormones, while the other choices do not play a direct role in supporting thyroid function.

Correct Answer: D

Rationale: The correct answer is D because the mitral valve separates the left atrium and left ventricle. Blood flows from the left atrium through the mitral valve into the left ventricle. The other choices are incorrect because the tricuspid valve separates the right atrium and right ventricle (choice B), the pulmonary valve separates the right ventricle and pulmonary artery, and the aortic valve separates the left ventricle and aorta.

Correct Answer: B

Rationale: The correct answer is B, the Digestive system. The esophagus is a muscular tube that connects the throat to the stomach, playing a crucial role in the digestion process by transporting food to the stomach through peristaltic movements. This is why it belongs to the Digestive system. Choice A, the Endocrine system, is incorrect because this system is responsible for producing and regulating hormones, not for the physical transport of food. Choice C, the Respiratory system, is incorrect as the esophagus is not involved in the exchange of gases, which is the primary function of the Respiratory system. Choice D, the Nervous system, is incorrect as the esophagus is not primarily responsible for transmitting nerve signals but rather for the mechanical process of moving food.

Correct Answer: B

Rationale: The correct answer is B: The nervous system tells the muscles how to respond to the environment. The nervous system communicates with muscles through motor neurons, sending signals to control muscle contractions in response to stimuli. This coordination allows for movement and responses to the environment. Incorrect choices: A: The muscles do not produce chemicals to feed the nerves; rather, nerves control muscle function. C: The nervous system does not primarily remove excess waste from muscles; this is mainly the job of the circulatory and lymphatic systems. D: The muscular system does not provide input for the nerves to make decisions; nerves regulate muscle activity based on external and internal signals.