What happens first in dehydration?
- A. Intercellular fluid volume drops first.
- B. Plasma volume drops first.
- C. Interstitial fluid drops first.
- D. Neither interstitial nor intracellular fluid volume are affected.
Correct Answer: C
Rationale: In dehydration, the body first draws fluid from the interstitial space to maintain blood volume, leading to a decrease in interstitial fluid volume. This is why choice C is correct. Choice A is incorrect because intracellular fluid is not the first to be affected. Choice B is also incorrect as plasma volume reduction typically occurs after interstitial fluid loss. Choice D is incorrect as dehydration impacts both interstitial and intracellular fluid volumes.
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Which organ has the greatest effect on fluid output?
- A. Kidneys
- B. Lungs
- C. Skin
- D. Intestines
Correct Answer: A
Rationale: The correct answer is the kidneys. The kidneys are primarily responsible for regulating fluid balance by filtering blood and adjusting the volume and concentration of urine. The lungs primarily regulate gas exchange, not fluid balance. The skin plays a role in temperature regulation and protection but is not the primary organ for fluid output. The intestines are mainly involved in the absorption of nutrients and water, rather than fluid output.
Which of the following is not considered an extracellular fluid?
- A. Cerebrospinal fluid
- B. The humors of the eye
- C. Lymph
- D. Cerebrospinal fluid and the humors of the eye
Correct Answer: D
Rationale: The correct answer is D. Cerebrospinal fluid and the humors of the eye are not considered extracellular fluids. Extracellular fluids are fluids found outside the cells, such as interstitial fluid and lymph. Cerebrospinal fluid is found within the central nervous system, while the humors of the eye (aqueous humor and vitreous humor) are located within the eyeball, making them distinct from extracellular fluids.
Which negative ion is most important in intracellular fluid?
- A. Phosphate ions.
- B. Protein molecules.
- C. Chlorine.
- D. Phosphate ions and protein molecules.
Correct Answer: D
Rationale: Intracellular fluid contains phosphate ions and protein molecules as essential anions. Phosphate ions play a crucial role in various cellular processes, including energy transfer. Proteins, being large molecules with negative charges, also contribute significantly to the negative ion concentration within cells. Chlorine is primarily an extracellular anion and is not as prominent as phosphate ions and proteins within intracellular fluid, making it a less important negative ion in this context. Therefore, the correct answer is D because both phosphate ions and protein molecules are crucial negative ions in intracellular fluid.
Which of the following are sources of water intake?
- A. Drinking fluids.
- B. Consuming water from the food we eat.
- C. Water from metabolic processes.
- D. Drinking fluids, consuming water from the food we eat, and water from metabolic processes.
Correct Answer: D
Rationale: The correct answer is D. The sources of water intake include drinking fluids, consuming water from the food we eat, and water from metabolic processes. Water intake is not solely from the liquids we drink but also from the water content present in the food we consume and the water produced during metabolic processes such as cellular respiration. Therefore, option D is the correct answer as it covers all the sources of water intake. Options A, B, and C alone do not encompass all the sources of water intake, making them incorrect choices.
The chief mechanism for maintaining fluid balance is to:
- A. adjust fluid intake so it equals fluid output.
- B. adjust fluid intake so it is slightly above fluid output.
- C. adjust fluid output so it equals fluid input.
- D. adjust fluid intake so it is slightly below fluid output.
Correct Answer: C
Rationale: The correct answer is C: 'adjust fluid output so it equals fluid input.' Maintaining fluid balance involves ensuring that the amount of fluid lost through processes like urination, sweating, and respiration equals the amount of fluid taken in. This ensures that the body stays properly hydrated. Choices A, B, and D are incorrect because they do not focus on the balance between fluid input and output, which is crucial for maintaining proper fluid balance. By adjusting fluid output to equal fluid input, the body can regulate hydration levels effectively, preventing dehydration or overhydration.