ATI Nutrition Proctored Exam

Correct Answer: B

Rationale: The correct answer is B. Magnesium plays an important role in maintaining calcium homeostasis and preventing skeletal abnormalities. It is involved in more than 300 enzymatic reactions, including energy metabolism, insulin activity, and glucose use. Magnesium is vital to the structural integrity of heart muscle and other muscles and nerves. While magnesium does play a role in blood clotting, nerve impulses, muscle contraction, relaxation, ATP energy release, and metabolism of fats, carbohydrates, proteins, the primary physiologic role of magnesium in the body is related to calcium homeostasis and maintaining the structural integrity of the heart muscle. Choice A is incorrect because it includes functions of magnesium, but they are not its primary physiologic role. Choice C is incorrect as magnesium has several known metabolic functions. Choice D is incorrect because although magnesium is involved in ATP energy release and metabolism, its primary role is related to calcium homeostasis and structural integrity of muscle.

Correct Answer: A

Rationale: The principal cation in plasma and interstitial fluid is sodium. Sodium plays a crucial role in maintaining fluid balance and is the primary cation in extracellular fluids like plasma and interstitial fluid. Potassium is the primary cation within cells, not in extracellular fluids, making it an incorrect choice. Calcium and magnesium are essential minerals but are not the principal cations in plasma and interstitial fluid, so they are also incorrect choices.

Correct Answer: C

Rationale: The statement is correct, but the reason is not correct. A major difference between fat-soluble and water-soluble vitamins is that the body is able to store larger amounts of fat-soluble vitamins. Vitamins A and D are stored for long periods; therefore, minor shortages might not be identified until drastic depletion has occurred. Observable signs and symptoms of a dietary deficiency are often not identified until they are in an advanced state. Water-soluble vitamins, on the other hand, are not stored in the body and are excreted in the urine if taken in excess, making it harder to reach toxic levels.

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: 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.