What state will the body be in if the ingestion and metabolic synthesis of a substance is less than its metabolic utilization and excretion?

Correct Answer: C

Rationale: Step 1: Ingestion and metabolic synthesis less than utilization and excretion result in a deficit. Step 2: A negative balance occurs when there is a deficit in the body's overall substance levels. Step 3: Negative balance indicates that the body is losing more of the substance than it is gaining. Therefore, choice C (negative balance) is correct as it accurately describes the state of the body in this scenario. Choices A, B, and D are incorrect because they do not reflect the concept of a deficit in substance levels as seen in a negative balance.

Correct Answer: A

Rationale: The correct answer is A (0 percent) because interstitial fluid is the fluid that surrounds the cells outside of the cell membrane, not the fluid within the cells themselves. Intracellular fluid refers to the fluid inside the cells, which does not include interstitial fluid. Therefore, interstitial fluid does not make up any percentage of intracellular fluid. Explanation for other choices: B: 25 percent - This is incorrect because interstitial fluid is not part of intracellular fluid, so it cannot make up a percentage of it. C: 50 percent - This is incorrect as well for the same reason as above. D: 75 percent - This is also incorrect because interstitial fluid is not part of intracellular fluid at all.

Correct Answer: D

Rationale: The correct answer is D because plasma and interstitial fluid are in dynamic equilibrium and do exchange materials through capillary walls. Changing the composition of one affects the other due to this exchange. Choice A is incorrect because plasma and interstitial fluid have some differences. Choice B is incorrect as capillary walls allow for exchange. Choice C is incorrect as proteins are restricted from freely passing through capillary walls.

Correct Answer: B

Rationale: The correct answer is B: plasma proteins. Plasma proteins contribute the vast majority of extracellular fluid's osmotic activity due to their high concentration and large size, which results in significant osmotic pressure. This osmotic pressure helps maintain fluid balance and regulate the movement of water between compartments. Na+ and its attendant anions (Choice A) are important for fluid balance but do not contribute significantly to osmotic activity. K+ and its attendant anions (Choice C) are mainly intracellular ions and do not play a major role in extracellular osmotic activity. Ca2+ and its attendant anions (Choice D) are essential for various cellular functions but do not contribute significantly to extracellular osmotic activity.

Correct Answer: B

Rationale: Correct Answer: B - Decreased K+ in the ECF Rationale: 1. Renin is released by the kidneys in response to decreased arterial blood pressure (A), decreased plasma volume (C), and decreased Na+ in the ECF (D). 2. Aldosterone release is stimulated by decreased plasma volume and decreased Na+ in the ECF, but not by decreased K+ in the ECF. 3. The renin-angiotensin-aldosterone system is primarily involved in regulating Na+ and water balance, not K+ levels. Summary: A, C, and D are incorrect because they can trigger the renin-angiotensin-aldosterone system. Choice B is the correct answer as decreased K+ levels do not directly activate this system.