Nokea
Which of the following does not act as a second messenger in second-messenger systems of hormone action?
- A. cyclic AMP
- B. calmodulin
- C. cyclic GMP
- D. inositol triphosphate
Correct Answer: B
Rationale: Calmodulin is not a second messenger but a calcium-binding protein that regulates various cellular processes. Cyclic AMP, cyclic GMP, and inositol triphosphate are all second messengers involved in hormone action. Calmodulin acts downstream of these second messengers to mediate their effects.
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All of the following are hormones of the anterior pituitary except:
- A. Growth hormone
- B. Follicle stimulating hormone
- C. Parthormone
- D. Thyroid stimulating hormone
Correct Answer: C
Rationale: The correct answer is C: Parthormone. The anterior pituitary gland secretes hormones such as Growth hormone, Follicle stimulating hormone, and Thyroid stimulating hormone, but not Parthormone. Parthormone is actually produced by the parathyroid glands, not the anterior pituitary gland. Parathormone plays a key role in regulating calcium levels in the blood. Therefore, choice C is incorrect as it does not belong to the hormones secreted by the anterior pituitary gland.
Mole for mole, which of the following has the greatest effect on Na+ excretion?
- A. Progesterone
- B. Cortisol
- C. Vasopressin
- D. Aldosterone
Correct Answer: D
Rationale: The correct answer is D: Aldosterone. Aldosterone directly influences the reabsorption of sodium in the kidney tubules, leading to increased Na+ excretion. Progesterone (A) does not have a significant effect on Na+ excretion. Cortisol (B) mainly affects glucose metabolism and has minimal impact on Na+ excretion. Vasopressin (C) primarily regulates water reabsorption, not Na+ excretion. Therefore, Aldosterone has the greatest effect on Na+ excretion due to its specific role in sodium reabsorption in the kidneys.
Which is NOT part of the normal content of gastric juice?
- A. HPO42-
- B. mucus
- C. lipase
- D. amylase
Correct Answer: D
Rationale: The correct answer is D: amylase. Gastric juice primarily contains hydrochloric acid, pepsinogen, and mucus, but not amylase. Amylase is an enzyme produced in the mouth and pancreas that helps break down carbohydrates, not typically found in gastric juice. HPO42- is a phosphate ion present in gastric juice. Lipase is an enzyme that aids in the digestion of fats and can be found in pancreatic juice, not gastric juice. Mucus is secreted by the stomach lining to protect it from the acidic environment of gastric juice.
What two effects does PTH exert on the kidneys?
- A. Blocks sodium reabsorption and increases the excretion of water.
- B. Increases calcium reabsorption and increases the excretion of phosphate in the urine.
- C. Decreases the reabsorption of both calcium and phosphate.
- D. Increases the excretion of H+ and the excretion of bicarbonate.
Correct Answer: B
Rationale: The correct answer is B because PTH (Parathyroid Hormone) acts on the kidneys by increasing calcium reabsorption and increasing the excretion of phosphate in the urine. PTH stimulates the kidney to reabsorb more calcium to maintain normal blood calcium levels. It also enhances the excretion of phosphate in the urine, helping to lower blood phosphate levels. Option A is incorrect because PTH does not block sodium reabsorption or increase water excretion in the kidneys. Option C is incorrect as PTH does not decrease the reabsorption of both calcium and phosphate. Option D is incorrect because PTH does not increase the excretion of H+ or bicarbonate.
You are providing care for a patient who underwent thyroidectomy 2 days ago. Which laboratory value requires close monitoring?
- A. Calcium
- B. Sodium
- C. Potassium
- D. White blood cells
Correct Answer: A
Rationale: Calcium levels should be closely monitored after a thyroidectomy due to the risk of hypocalcemia caused by damage or removal of the parathyroid glands.