You are the surgical nurse caring for a 65-year-old female patient who is postoperative day 1 following a thyroidectomy. During your shift assessment, the patient complains of tingling in her lips and fingers. She tells you that she has an intermittent spasm in her wrist and hand, and she exhibits increased muscle tone. What electrolyte imbalance should you first suspect?

Correct Answer: B

Rationale: The symptoms described, including tingling in the lips and fingers, intermittent spasms, and increased muscle tone, are indicative of tetany, which is a common manifestation of hypocalcemia. Hypocalcemia can lead to neuromuscular irritability, causing symptoms such as paresthesias and muscle spasms. Hypophosphatemia primarily affects the central nervous system, resulting in seizures and coma. Hypermagnesemia typically presents with hypoactive reflexes and somnolence. Hyperkalemia can cause paresthesias and anxiety, but in this case, the patient's symptoms are more suggestive of hypocalcemia.

Correct Answer: C

Rationale: Dehydration leads to a decrease in the body's fluid levels, causing the salivary glands to produce less saliva, resulting in a 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 but decrease during dehydration.

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 incorrect as it states that electrolytes dissociate but do not form ions, which is inaccurate as electrolytes do form ions in water solutions. Choice C is also incorrect as it states that electrolytes form ions but may not necessarily dissociate, which goes against the definition of electrolytes that must dissociate into ions for conductivity. Therefore, choice D is the most accurate as it correctly describes that electrolytes dissociate in water solutions and form ions, highlighting the essential characteristics of electrolytes.

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.

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. Bicarbonate (Choice A) is important for buffering acids in the body but is not the most abundant negative ion in blood plasma. Hydroxide (Choice C) is not typically found in high concentrations in blood plasma. Phosphate (Choice D) is an important anion in the body but is not as abundant as chloride in blood plasma.