Which vitamin acts most like a hormone?

Correct Answer: C

Rationale: The correct answer is Vitamin D. Although vitamin D, also known as calciferol, has been called a vitamin, it is more appropriately classified as a hormone. Like hormones, vitamin D acts to control the function of other cell types. For example, it helps the body absorb and regulate skeletal calcium and phosphorus levels. Choice A (Vitamin A) plays a crucial role in vision and immune function. Choice B (Vitamin B) is a complex of different vitamins that play various roles in the body. Choice D (Vitamin C) is important for collagen production and acts as an antioxidant.

Correct Answer: A

Rationale: Both statements are true. When rickets occurs, the alveolar bone is affected similar to other bones in the body, with the trabeculae of the alveolar bone also weakening. In addition to damaged alveolar bone caused by vitamin D deficiency, dental changes include delayed dentition and small molars. The other choices are incorrect because both statements provided are accurate based on the effects of rickets on the alveolar bone.

Correct Answer: D

Rationale: The correct answer is D. Calcium within saliva does not increase dental caries; in fact, the buffering action provided by calcium and phosphate in saliva inhibits caries formation by preventing the dissolution of enamel by plaque biofilm. Choice A is correct as saliva is indeed supersaturated with calcium. Choice B is correct as saliva serves as a source of calcium to mineralize an immature or demineralized enamel surface. Choice C is correct as calcium and phosphate in saliva do provide a buffering action to protect teeth from acids.

Correct Answer: A

Rationale: Both the statement and the reason are correct and related. Milk and other dairy products are indeed preferred sources of calcium because they supply most of the available calcium. Additionally, lactose present in dairy products enhances calcium absorption, making them even more efficient sources of this essential mineral. The statement correctly identifies dairy products as preferred sources of calcium, and the reason explains how lactose contributes to better calcium absorption. The other choices are incorrect as they do not accurately assess the relationship between lactose, calcium absorption, and the preference for dairy products as sources of calcium.

Correct Answer: C

Rationale: The hypothalamus, located in the middle of the brain, plays a crucial role in regulating hunger and satiety. It contains specific regions that control appetite and feeding behavior. The Medulla Oblongata (Choice A) is responsible for regulating vital functions like heartbeat and breathing, not hunger. The Pituitary Gland (Choice B) is an endocrine gland that secretes hormones but is not primarily involved in hunger regulation. The Parathyroid (Choice D) is responsible for regulating calcium levels in the body and not related to hunger or satiety.