Anatomy HESI A2

Correct Answer: A

Rationale: The correct answer is A: To break down proteins. Pepsin is an enzyme produced in the stomach that specifically functions to break down proteins into smaller peptides. This process is crucial for the digestion and absorption of proteins in the body. Pepsin works optimally in the acidic environment of the stomach. Choices B, C, and D are incorrect because pepsin is not involved in breaking down starches, emulsifying fats and oils, or absorbing water and nutrients. Other enzymes like amylase are responsible for breaking down starches, bile helps emulsify fats, and various enzymes and mechanisms are involved in water and nutrient absorption in the digestive system.

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: B

Rationale: The epidermis is classified as a tissue. Tissue is a group of cells that work together to perform a specific function. The epidermis is composed of multiple layers of cells that protect underlying tissues. It does not meet the criteria of being a single cell (choice A), an organ (choice C), or a system (choice D). It is not a single cell because it is made up of multiple layers of cells. It is not an organ because an organ is a collection of tissues working together. It is not a system because a system is a group of organs working together. Therefore, the correct classification for the epidermis is a tissue.

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: C

Rationale: The correct answer is C: Parathyroid. The parathyroid gland controls Calciferol (Vitamin D) levels in the body by regulating calcium and phosphorus metabolism. The thyroid gland (choice A) regulates metabolism but not specifically Calciferol. The pituitary gland (choice B) controls various hormones but not Calciferol. The hypothalamus (choice D) regulates the release of hormones from the pituitary gland but does not directly control Calciferol. Therefore, the parathyroid gland is the correct choice for controlling Calciferol levels in the body.