Cerebrospinal fluid is an example of which type of fluid?

Correct Answer: A

Rationale: The correct answer is A: interstitial. Cerebrospinal fluid is a clear, colorless fluid found in the subarachnoid space of the brain and spinal cord. It is produced by the choroid plexus in the brain's ventricles and functions to cushion the brain, provide nutrients, and remove waste. Interstitial fluid is the fluid that surrounds cells in the body, providing them with nutrients and removing waste. Cerebrospinal fluid is similar to interstitial fluid in composition and function, making it an example of interstitial fluid. Choices B, C, and D are incorrect because intracellular fluid is inside cells, transcellular fluid is found in body cavities like synovial fluid, and lymph is a fluid in the lymphatic system, not comparable to cerebrospinal fluid.

Correct Answer: A

Rationale: The correct answer is A: to maintain blood pressure. Extracellular fluid volume regulation is crucial for maintaining blood pressure within a normal range. Any imbalance in extracellular fluid volume can lead to changes in blood pressure, potentially causing issues like hypotension or hypertension. Adequate blood pressure is necessary for proper perfusion of organs and tissues. Choice B (to maintain adequate urine formation) is incorrect because extracellular fluid volume regulation primarily affects blood pressure, not urine formation. Choice C (to prevent changes in ICF osmolarity) is incorrect because extracellular fluid volume regulation does not directly impact intracellular fluid osmolarity. Choice D (to prevent cells from swelling or shrinking) is incorrect because intracellular fluid volume regulation, not extracellular fluid volume, is primarily responsible for preventing cellular swelling or shrinking.

Correct Answer: C

Rationale: The correct answer is C because an increase in sodium reabsorption would be triggered by a drop in arterial blood pressure, not a decrease. When arterial blood pressure drops, the body aims to retain sodium and water to increase blood volume and pressure. Choices A, B, and D are incorrect as they are all actions that would be triggered by a drop in arterial blood pressure. A decrease in glomerular filtration rate (GFR) helps conserve fluids and maintain blood pressure, release of aldosterone promotes sodium and water retention, and a decrease in chloride excretion also helps in retaining fluids. Therefore, an increase in sodium reabsorption is the action NOT triggered by a drop in arterial blood pressure.

Correct Answer: D

Rationale: The correct answer is D: water retention. Water intoxication leads to dilution of electrolytes in the body, causing intracellular fluid (ICF) hypotonicity and circulatory extracellular fluid (ECF) hypotonicity. Excess free water intake can overwhelm the kidneys' ability to excrete it, resulting in hyponatremia. Water retention, on the other hand, implies the body is holding onto water, which is not a characteristic of water intoxication where excess water is typically excreted. Therefore, water retention does not occur during water intoxication.

Correct Answer: D

Rationale: The correct answer is D because when the rate of CO removal by the lungs is less than the rate of CO production by the tissues, more CO builds up in the body. This excess CO leads to increased generation of H+ ions due to the breakdown of CO into H+ ions and carbon. This acidic environment from the increased H+ ions can disrupt the body's pH balance. Choice A is incorrect because the rate of protein catabolism and anabolism does not directly impact the generation of H+ from CO. Choice B is also incorrect because the speed of protein breakdown and synthesis does not affect the generation of H+ from CO. Choice C is incorrect because the rate of CO removal by the lungs being higher than CO production does not lead to an increase in H+ generation.