Which electrolyte is important in the formation of the thyroid hormones?
- A. Sodium
- B. Iodine
- C. Iron
- D. Chloride
Correct Answer: B
Rationale: Iodine is the correct answer because it is essential for the synthesis of thyroid hormones. The thyroid gland incorporates iodine into thyroid hormones such as thyroxine (T4) and triiodothyronine (T3). These hormones are crucial for regulating metabolism, growth, and development. Sodium, iron, and chloride are not directly involved in the formation of thyroid hormones, making them incorrect choices.
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You are working on a burns unit, and one of your acutely ill patients is exhibiting signs and symptoms of third spacing. Based on this change in status, you should expect the patient to exhibit signs and symptoms of what imbalance?
- A. Metabolic alkalosis
- B. Hypermagnesemia
- C. Hypercalcemia
- D. Hypovolemia
Correct Answer: D
Rationale: When a patient exhibits signs and symptoms of third-spacing, where fluid moves out of the intravascular space but not into the intracellular space, hypovolemia is expected. This leads to a decreased circulating blood volume. Increased calcium and magnesium levels are not typically associated with third-spacing fluid shift. Burns usually result in acidosis rather than alkalosis, making metabolic alkalosis an incorrect choice. Therefore, hypovolemia is the correct answer in this scenario.
What is the main water-holding force in the blood capillaries?
- A. Capillary blood pressure
- B. Sodium in the blood plasma
- C. Protein in the blood plasma
- D. Chloride in the blood plasma
Correct Answer: C
Rationale: The correct answer is C: Protein in the blood plasma. Plasma proteins, especially albumin, create oncotic pressure, which is the main force responsible for holding water within the blood capillaries. Capillary blood pressure (Choice A) is involved in pushing blood through the capillaries, while sodium and chloride in the blood plasma (Choices B and D) are electrolytes and do not play a significant role in the water-holding force within capillaries.
Which substance dissociates into ions in a water solution?
- A. Intracellular fluid
- B. Interstitial fluid
- C. Plasma
- D. Electrolyte
Correct Answer: D
Rationale: The correct answer is 'Electrolyte.' Electrolytes are substances that dissociate into ions when dissolved in water. Intracellular fluid, interstitial fluid, and plasma are not substances that dissociate into ions in a water solution. Intracellular fluid is the fluid inside cells, interstitial fluid is the fluid between cells, and plasma is the liquid component of blood. These choices do not dissociate into ions in a water solution, unlike electrolytes.
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.
Retention of electrolytes (especially sodium) in the interstitial fluid can result from:
- A. decreased aldosterone secretion.
- B. increased ADH secretion.
- C. increased aldosterone secretion.
- D. decreased ADH secretion.
Correct Answer: C
Rationale: The correct answer is C: increased aldosterone secretion. Aldosterone, a hormone produced by the adrenal glands, increases sodium reabsorption in the kidneys, leading to retention of sodium and water in the interstitial fluid. Increased aldosterone secretion enhances the reabsorption of sodium, thereby increasing its retention. Choice A is incorrect because decreased aldosterone secretion would lead to less sodium reabsorption and increased excretion. Choice B is incorrect because increased ADH secretion primarily affects water reabsorption rather than sodium. Choice D is incorrect because decreased ADH secretion would lead to increased water excretion but not necessarily affect sodium retention.