Nokea
Which of the following is an alpha-blocker used in the treatment of hypertension:
- A. Tyramine
- B. Prazosin
- C. Ergometrine
- D. Ergotamine
Correct Answer: B
Rationale: Step 1: Understand the question is about an alpha-blocker for hypertension.
Step 2: Identify Prazosin as an alpha-blocker used for hypertension by blocking alpha-1 receptors.
Step 3: Explain how Prazosin works to dilate blood vessels and lower blood pressure.
Step 4: Summarize why other choices are incorrect:
- A: Tyramine is not an alpha-blocker, it is found in certain foods.
- C: Ergometrine is an ergot alkaloid used for uterine contractions, not hypertension.
- D: Ergotamine is also an ergot alkaloid used for migraines, not hypertension.
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Which of the following hormones acts on its target tissues by a steroid hormone mechanism of action?
- A. Thyroid hormone
- B. Parathyroid hormone (PTH)
- C. Antidiuretic hormone (ADH) on the collecting duct
- D. β1 adrenergic agonists
Correct Answer: A
Rationale: The correct answer is A: Thyroid hormone. Thyroid hormone acts on its target tissues by a steroid hormone mechanism of action because it is a lipid-soluble hormone that can diffuse through cell membranes and bind to intracellular receptors. These hormone-receptor complexes then directly regulate gene expression. In contrast, choices B, C, and D do not follow a steroid hormone mechanism of action. Parathyroid hormone (PTH) acts through G-protein coupled receptors, Antidiuretic hormone (ADH) acts through V2 receptors, and β1 adrenergic agonists act through beta-adrenergic receptors, which are all distinct from the mechanism of action of steroid hormones.
What is observed when aqueous silver nitrate is added to this mixture?
- A. white precipitate
- B. white solution
- C. yellow precipitate
- D. yellow solution
Correct Answer: C
Rationale: When aqueous silver nitrate is added to a mixture, a yellow precipitate forms if there are chloride ions present. This is due to the formation of silver chloride, which is insoluble in water. The reaction is AgNO3 + Cl- → AgCl↓ + NO3-. Therefore, choice C is correct.
Choice A (white precipitate) is incorrect because silver chloride is yellow, not white. Choice B (white solution) is incorrect as a precipitate forms, not a solution. Choice D (yellow solution) is incorrect because the product is a solid precipitate, not a solution.
Which is not a function of the hypothalamus?
- A. Affect heart rate
- B. Control temperature
- C. Affect water balance
- D. Secrete FSH
Correct Answer: D
Rationale: The correct answer is D: Secrete FSH. The hypothalamus produces releasing and inhibiting hormones that regulate the pituitary gland's secretion of hormones such as FSH. The hypothalamus itself does not secrete FSH. A, B, and C are functions of the hypothalamus as it is involved in regulating heart rate, temperature control, and water balance through various hormonal and neural pathways.
How do hormones affect target tissues?
- A. Hormones affect target tissues through the digestive system.
- B. Hormones affect target tissues through the nervous system.
- C. Hormones secrete mucus that then travels to target tissues.
- D. Hormones travel directly to target tissues and bind to receptors.
Correct Answer: D
Rationale: The correct answer is D because hormones are released into the bloodstream by endocrine glands and travel to specific target tissues, where they bind to receptors on the surface or within the cells. This binding triggers a series of cellular responses that regulate various physiological processes. Choices A, B, and C are incorrect because hormones do not affect target tissues through the digestive system, nervous system, or by secreting mucus. Hormones act specifically by binding to receptors on target cells to initiate their effects.
A child visiting his grandfather at his farm returns home having fever, skin flush, dry mouth, constipation, dilated pupils, and increased heart rate. Which of the following could be the offending agent:
- A. Eating seeds containing atropine
- B. Exposure to malathion insecticide
- C. Wrong intake of echothiophate drops
- D. Ingestion of physostigmine
Correct Answer: A
Rationale: The correct answer is A: Eating seeds containing atropine. Atropine is a plant alkaloid commonly found in certain seeds that can cause symptoms such as fever, skin flush, dry mouth, constipation, dilated pupils, and increased heart rate when ingested. Atropine is known to have anticholinergic effects, which align with the symptoms presented by the child. Malathion (B) is an insecticide that typically causes different symptoms like nausea, vomiting, and diarrhea. Echothiophate drops (C) are cholinesterase inhibitors used in the treatment of glaucoma, which would not produce the described symptoms. Physostigmine (D) is a cholinesterase inhibitor that would not cause symptoms of anticholinergic toxicity seen in the child.