ATI RN

1. When does dehydration begin to occur?

• A. the body reduces fluid output to zero.
• B. the body increases the release of ANH.
• C. the salivary secretions decrease.
• D. the salivary secretions increase.

Correct Answer: C

Rationale: Dehydration leads to a decrease in the body's fluid levels, causing the salivary glands to produce less saliva, which results in dry mouth. Therefore, when dehydration begins to occur, salivary secretions decrease. Choice A is incorrect because the body does not reduce fluid output to zero during dehydration; it tries to conserve fluids. Choice B is incorrect as dehydration does not directly increase the release of ANH (Atrial Natriuretic Hormone). Choice D is incorrect because salivary secretions do not increase during dehydration.

2. Electrolytes:

• A. form when glucose is added to water.
• B. dissociate in water solutions.
• C. form ions in water solutions.
• D. dissociate in water solutions and form ions in water solutions.

Correct Answer: D

Rationale: The correct answer is D. Electrolytes are substances that dissociate into ions when dissolved in water, allowing the solution to conduct electricity. Choice A is incorrect because glucose does not form electrolytes when added to water. Choice B is partially correct as electrolytes do dissociate in water solutions, but it does not mention the formation of ions, which is crucial. Choice C is also partially correct as electrolytes do form ions in water solutions, but it does not mention the dissociation process required for conductivity. Therefore, choice D is the most accurate as it combines both dissociation and ion formation in water solutions, which are key characteristics of electrolytes.

3. What is the most abundant positive ion in blood plasma?

• A. Potassium.
• B. Calcium.
• C. Sodium.
• D. Both potassium and sodium are in equal concentrations.

Correct Answer: C

Rationale: The correct answer is C: Sodium. Sodium (Na+) is the most abundant cation in the extracellular fluid, including blood plasma. It plays a crucial role in maintaining fluid balance, nerve function, and is essential for various physiological processes. Choice A, Potassium, is also an important ion in the body but is predominantly found intracellularly. Choice B, Calcium, is an essential mineral in the body but is not the most abundant positive ion in blood plasma. Choice D is incorrect as sodium is the primary positive ion in blood plasma, with a much higher concentration compared to potassium.

4. Which negative ion is most abundant in blood plasma?

• A. Bicarbonate
• B. Chloride
• C. Hydroxide
• D. Phosphate

Correct Answer: B

Rationale: Chloride (Cl-) is the most abundant anion in blood plasma. It plays a crucial role in maintaining osmotic balance and acid-base homeostasis. Choice A, bicarbonate, is important for buffering acids in the body but is not the most abundant negative ion in blood plasma. Choice C, hydroxide, is not typically found in high concentrations in blood plasma. Choice D, phosphate, is an important anion in the body but is not as abundant as chloride in blood plasma.

5. Which mineral is important in hemoglobin production?

• A. Sodium
• B. Iodine
• C. Iron
• D. Chloride

Correct Answer: C

Rationale: Iron (Fe) is a critical mineral in hemoglobin production. Hemoglobin is a protein found in red blood cells that is essential for transporting oxygen throughout the body. Sodium (Choice A), Iodine (Choice B), and Chloride (Choice D) are not directly involved in hemoglobin production.