Nokea
The actions of gastrin include all but:
- A. insulin secretion in response to a carbohydrate meal
- B. a trophic effect on colonic mucosa
- C. a trophic effect on gastric mucosa
- D. pepsin secretion
Correct Answer: A
Rationale: The correct answer is A because gastrin primarily stimulates gastric acid secretion and gastric mucosal growth but not insulin secretion. Gastrin acts on parietal cells to stimulate acid production and chief cells to release pepsinogen. Choice B and C are incorrect as gastrin does have a trophic effect on colonic and gastric mucosa, respectively. Choice D is also incorrect as gastrin stimulates pepsin secretion.
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Pralidoxime is a cholinesterase reactivator used in the treatment of toxicity by:
- A. Atropine
- B. Nicotine
- C. Organic phosphate
- D. Amphetamine
Correct Answer: C
Rationale: The correct answer is C: Organic phosphate. Pralidoxime is used to treat toxicity caused by organophosphates, which inhibit cholinesterase enzymes. Pralidoxime works by reactivating the inhibited cholinesterase enzymes, restoring their function. Atropine is used to counteract the effects of excessive acetylcholine in cholinergic toxicity, not organophosphate poisoning. Nicotine is a nicotinic receptor agonist and not treated with pralidoxime. Amphetamine is a central nervous system stimulant and does not involve cholinesterase inhibition. Therefore, the correct answer is C as pralidoxime is specifically used to treat toxicity caused by organophosphates.
Which of the following is not a steroid-based hormone?
- A. estrogen
- B. aldosterone
- C. epinephrine
- D. cortisone
Correct Answer: C
Rationale: The correct answer is C: epinephrine. Steroid-based hormones are derived from cholesterol and include estrogen, aldosterone, and cortisone. Epinephrine is a catecholamine hormone, not a steroid hormone. Catecholamines are derived from the amino acid tyrosine, not cholesterol like steroid hormones. Therefore, epinephrine does not belong to the category of steroid-based hormones.
Which of the following is NOT a symptom of Addison’s disease?
- A. Salt craving
- B. Weight gain
- C. Hypoglycemia
- D. Hyperpigmentation
Correct Answer: B
Rationale: The correct answer is B: Weight gain. Addison's disease is characterized by adrenal insufficiency, leading to symptoms such as salt craving, hypoglycemia, and hyperpigmentation due to increased melanin production. Weight loss, not weight gain, is commonly associated with Addison's disease due to decreased cortisol levels. Salt craving is due to sodium loss, hypoglycemia results from insufficient cortisol levels, and hyperpigmentation is caused by elevated ACTH levels stimulating melanin production. Weight gain is not a typical symptom, making it the correct answer.
Which row shows the correct order of reactivity for the elements?
- A. silver, calcium, carbon, potassium
- B. silver, carbon, calcium, potassium
- C. sodium, hydrogen, zinc, gold
- D. sodium, zinc, hydrogen, gold
Correct Answer: D
Rationale: The correct order of reactivity for elements is based on their tendency to lose electrons. In this case, sodium is the most reactive as it readily loses an electron to form a stable ion. Zinc is less reactive compared to sodium but more reactive than hydrogen and gold. Hydrogen is less reactive than both zinc and sodium. Gold is the least reactive among the options given. Therefore, the correct order of reactivity is sodium > zinc > hydrogen > gold, which matches option D. Choices A, B, and C do not follow the correct order of reactivity for the elements listed, making them incorrect.
The body’s major metabolic hormone is released from the:
- A. Pituitary
- B. Thyroid
- C. Thymus
- D. Hypothalamus
Correct Answer: B
Rationale: The correct answer is B: Thyroid. The body's major metabolic hormone, thyroxine (T4) and triiodothyronine (T3), is released from the thyroid gland. The thyroid gland plays a crucial role in regulating metabolism. Pituitary (A) releases various hormones but not the major metabolic hormone. Thymus (C) is responsible for immune function, not metabolism. Hypothalamus (D) regulates the pituitary gland but does not directly release the major metabolic hormone.