HESI A2 Anatomy and Physiology Practice Exam

Correct Answer: B

Rationale: The correct answer is B because skeletal muscle attaches to bones by tendons, allowing for movement of the body. Tendons are tough connective tissues that anchor muscles to bones. This attachment enables the contraction of skeletal muscles to produce movement at the joints. Choices A, C, and D are incorrect. Skeletal muscle typically makes up around 40-50% of the body's weight, muscle contraction plays a role in temperature regulation through shivering, and skeletal muscles can contract even at rest due to maintaining posture or supporting the body.

Correct Answer: C

Rationale: The correct answer is C: Tofu. Tofu, made from soybeans, is a complete protein source, providing all essential amino acids needed by the body. It is a significant protein source for individuals on a vegan diet. Eggs (A) and fish (B) are animal products and not suitable for a vegan diet. Leafy greens (D) are not a significant source of protein compared to tofu and may not provide enough protein for a person following a vegan diet.

Correct Answer: D

Rationale: The correct answer is D, Integumentary system. Sebaceous glands are located in the skin, which is part of the integumentary system. These glands secrete sebum to lubricate and protect the skin. The endocrine system (choice A) regulates hormones, not sebum production. The digestive system (choice B) processes food, not related to sebaceous glands. The respiratory system (choice C) is responsible for gas exchange, not sebum secretion. Therefore, the integumentary system is the correct choice.

Correct Answer: D

Rationale: The correct answer is D: Melatonin. The pineal gland is responsible for producing melatonin, a hormone that regulates the sleep-wake cycle. It is released in response to darkness, helping to signal the body that it is time to sleep. Corticosteroid (A) is produced by the adrenal glands, oxytocin (B) is produced by the hypothalamus and released by the pituitary gland, and prolactin (C) is produced by the pituitary gland. Therefore, the correct answer is D as it directly relates to the function of the pineal gland.

Correct Answer: B

Rationale: The parathyroid hormone regulates calcium levels in the body. It does so by increasing the release of calcium from bones, promoting calcium absorption in the intestines, and reducing calcium excretion by the kidneys. This is crucial for maintaining proper bone density and nerve function. Choice A (Magnesium) is incorrect because the parathyroid hormone does not directly regulate magnesium levels. Choice C (Calcitonin) is incorrect because calcitonin, produced by the thyroid gland, works in opposition to parathyroid hormone to lower blood calcium levels. Choice D (Glucocorticoids) is incorrect because these hormones, produced by the adrenal glands, are involved in metabolism, immune response, and stress regulation, but not in calcium regulation.