Nokea
Which of the following hormones exerts negative feedback control on the secretion of ACTH?
- A. PTH
- B. Glucagon
- C. Cortisol
- D. Corticotrophin-releasing hormone
Correct Answer: C
Rationale: The correct answer is C: Cortisol. Cortisol exerts negative feedback control on the secretion of ACTH by inhibiting the release of corticotrophin-releasing hormone (CRH) and ACTH from the hypothalamus and pituitary gland, respectively. This feedback loop helps regulate the body's stress response and maintain hormone levels within a normal range.
A: PTH (Parathyroid Hormone) does not directly regulate the secretion of ACTH.
B: Glucagon regulates blood sugar levels and does not directly affect ACTH secretion.
D: Corticotrophin-releasing hormone (CRH) is the hormone that stimulates the release of ACTH, so it does not exert negative feedback control on ACTH secretion.
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Which stimulates parietal cell secretion?
- A. prostaglandins
- B. aspirin
- C. vinegar
- D. acetylcholine
Correct Answer: D
Rationale: The correct answer is D: acetylcholine. Parietal cells in the stomach are primarily stimulated by acetylcholine to secrete hydrochloric acid. Acetylcholine binds to muscarinic receptors on parietal cells, leading to an increase in intracellular calcium levels and subsequent acid secretion. Prostaglandins (choice A) actually inhibit acid secretion, making it an incorrect choice. Aspirin (choice B) is known to damage the gastric mucosa and does not directly stimulate parietal cells. Vinegar (choice C) is acidic but does not specifically target parietal cells for acid secretion. Therefore, the correct choice is acetylcholine as it directly stimulates parietal cell secretion through muscarinic receptors.
Underproduction of growth hormone during the growing years produces ______.
- A. myxedema.
- B. gigantism.
- C. pituitary dwarfism.
- D. acromegaly.
Correct Answer: C
Rationale: The correct answer is C: pituitary dwarfism. Growth hormone deficiency during growing years results in pituitary dwarfism due to stunted growth. Myxedema (choice A) is associated with hypothyroidism, not growth hormone deficiency. Gigantism (choice B) occurs due to excessive growth hormone production in childhood. Acromegaly (choice D) is caused by excess growth hormone in adulthood, not during the growing years. Thus, choice C is the most appropriate based on the impact of growth hormone deficiency on growth during childhood.
Which of the following is true about calcium homeostasis?
- A. Increased calcitonin levels will cause increased blood calcium levels.
- B. High calcium levels cause bone resorption.
- C. Parathyroid hormone causes an increase in osteoblast activity.
- D. Parathyroid hormone is the single most important regulator of calcium levels in the blood.
Correct Answer: D
Rationale: The correct answer is D: Parathyroid hormone is the single most important regulator of calcium levels in the blood. Parathyroid hormone plays a crucial role in maintaining calcium homeostasis by stimulating bone resorption, increasing calcium reabsorption in the kidneys, and activating vitamin D to enhance calcium absorption in the intestines. It acts to raise blood calcium levels when they are low.
Explanation for other choices:
A: Increased calcitonin levels actually lower blood calcium levels by promoting calcium deposition in bones.
B: High calcium levels do not cause bone resorption; it is actually the opposite as mentioned in choice D.
C: Parathyroid hormone does not increase osteoblast activity; it primarily affects osteoclasts to release calcium from bones.
In the emergency department, during initial assessment of a new admission with diabetes, you discover all of the following. Which information should you immediately report to the physician?
- A. Hammertoe of the left second metatarsophalangeal joint
- B. Rapid respiratory rate with deep inspirations
- C. Numbness and tingling bilaterally in feet and hands
- D. Decreased sensitivity and swelling of the abdomen
Correct Answer: B
Rationale: Rapid respiratory rate with deep inspirations may indicate diabetic ketoacidosis (DKA) or another metabolic disturbance and requires immediate intervention.
Monoamine oxidase enzyme (MAO) is responsible for:
- A. Adrenaline activation
- B. Adrenaline synthesis
- C. Adrenaline degradation
- D. Acetylcholine degradation
Correct Answer: C
Rationale: Monoamine oxidase enzyme (MAO) is responsible for the degradation of neurotransmitters like adrenaline. MAO breaks down adrenaline into inactive metabolites, regulating its levels in the body. This process is crucial for maintaining neurotransmitter balance. Choice A is incorrect because MAO does not activate adrenaline. Choice B is incorrect as MAO is not involved in adrenaline synthesis. Choice D is incorrect as MAO does not degrade acetylcholine, but rather neurotransmitters like serotonin, dopamine, and adrenaline.