Each statement is true of calcium within saliva, except one. Which is the exception?

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: C

Rationale: The correct answer is C, osmotic pressure. Osmotic pressure within the body equalizes the solute concentration of ICFs and ECFs by shifting small amounts of water in the direction of higher concentration solute. Semipermeable membranes separate one fluid compartment from another and do not directly equalize solute concentrations. Hydration and perspiration are important elements of fluid balance but do not directly achieve the equalization of solute concentrations between ICFs and ECFs, which is primarily regulated by osmotic pressure.

Correct Answer: B

Rationale: The correct answer is B. Water-soluble vitamins do not develop deficiencies rapidly because the body does not store them for long periods. They must be obtained through food constantly. Choice A is correct because water-soluble vitamins often act as coenzymes in various metabolic reactions. Choice C is correct as daily intake of water-soluble vitamins is necessary since they are not stored in the body. Choice D is incorrect as water-soluble vitamins are absorbed primarily in the small intestine, particularly in the duodenum and ileum, not the jejunum.

Correct Answer: A

Rationale: Both statements are true. Systemic diseases can often present with oral manifestations before other systemic signs appear. Additionally, oral diseases can have systemic implications by affecting a person's overall health, such as through inflammation or compromised nutrient intake. Choice B is incorrect because both statements are true, as supported by medical literature. Choice C is incorrect because the second statement is also true. Choice D is incorrect because the first statement is true.

Correct Answer: C

Rationale: Vitamin A can be stored in the liver to meet basic needs for at least 1 year. This storage capacity allows the body to have a reserve of Vitamin A to sustain its needs over an extended period. Choices A, B, and D are incorrect because they underestimate the storage capacity of Vitamin A in the liver, which can last longer than these durations.