Nokea
Which drug is most likely to cause muscle tremor:
- A. Ipratropium
- B. Terbutaline
- C. Atenolol
- D. Nicotinic acid
Correct Answer: B
Rationale: The correct answer is B: Terbutaline. Terbutaline is a beta-2 adrenergic agonist used as a bronchodilator. It can stimulate beta-2 receptors in skeletal muscle, leading to muscle tremors as a common side effect. Ipratropium (A) is an anticholinergic bronchodilator and typically does not cause muscle tremors. Atenolol (C) is a beta-blocker and is not associated with muscle tremors. Nicotinic acid (D) is used to treat dyslipidemia and does not commonly cause muscle tremors. Therefore, Terbutaline is the most likely drug to cause muscle tremor among the options provided.
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Ritodrine is a drug indicated for suppressing uterine contractions in premature labor. The drug also causes bronchodilation. It has no vasoconstrictor effects, nor any effects on the size of the pupil of the eye. Which of the following is the most likely classification of this drug?
- A. α-adrenergic agonist
- B. Antimuscarinic drug
- C. β-adrenergic agonist
- D. β-adrenergic blocker
Correct Answer: C
Rationale: The correct answer is C: β-adrenergic agonist. Ritodrine is indicated for suppressing uterine contractions, which is a typical effect of β-adrenergic agonists. Bronchodilation is also a known effect of β-adrenergic agonists. Since the drug has no vasoconstrictor effects and does not affect the size of the pupil of the eye, it is unlikely to be an α-adrenergic agonist or an antimuscarinic drug. Additionally, the fact that ritodrine causes bronchodilation further supports its classification as a β-adrenergic agonist.
Which of the following hormones helps conserve water during dehydration?
- A. Atrial natriuretic peptide
- B. Oxytocin
- C. Aldosterone
- D. Thyroxine
Correct Answer: C
Rationale: Aldosterone is the correct answer because it acts on the kidneys to increase reabsorption of sodium and water, helping conserve water during dehydration. Atrial natriuretic peptide promotes sodium excretion, oxytocin is involved in labor and milk ejection, and thyroxine regulates metabolism.
Regarding basal metabolic rate:
- A. it is higher in women
- B. it is determined at rest within 12 hours after the last meal
- C. increases by 18% for each 1°C of fever
- D. is about 40Kcal/m2/h in an average man
Correct Answer: D
Rationale: Basal metabolic rate (BMR) is the energy expended by the body at rest to maintain basic physiological functions. Choice D is correct because it states that BMR is about 40Kcal/m2/h in an average man, which is a commonly accepted value. This is based on the energy needed for essential bodily functions such as breathing, circulation, and cell production. Choices A, B, and C are incorrect because: A) BMR is generally higher in men due to their higher muscle mass; B) BMR is measured after an overnight fast, not within 12 hours after the last meal; C) Fever typically increases BMR by around 7% per 1°C rise, not 18%.
Steroids:
- A. are secreted by the adrenal medulla.
- B. include the glucocorticoids, mineralocorticoids, and androgens.
- C. stimulate the membranes of the target cells to produce the second chemical messenger, cAMP.
- D. are secreted by the pancreas.
Correct Answer: B
Rationale: The correct answer is B because steroids include glucocorticoids, mineralocorticoids, and androgens, which are hormones secreted by the adrenal cortex. Glucocorticoids regulate metabolism and immune response, mineralocorticoids regulate electrolyte balance, and androgens are male sex hormones.
Choice A is incorrect because steroids are secreted by the adrenal cortex, not the adrenal medulla. Choice C is incorrect because steroids act by entering the target cells and binding to intracellular receptors, not by stimulating second messengers like cAMP. Choice D is incorrect because steroids are not secreted by the pancreas; instead, the pancreas secretes hormones like insulin and glucagon.
Which of these is true of the endocrine system?
- A. secretes hormones that are transported to target cells by blood
- B. causes changes in metabolic activities
- C. effects are prolonged
- D. All of above are true.
Correct Answer: D
Rationale: Step 1: The endocrine system secretes hormones that travel through the bloodstream to specific target cells. (Choice A)
Step 2: These hormones regulate metabolic activities in the body. (Choice B)
Step 3: The effects of hormonal actions can last for an extended period, leading to prolonged effects. (Choice C)
Therefore, all the statements A, B, and C are true about the endocrine system, making choice D the correct answer. Other choices are incorrect as they do not encompass all aspects of the endocrine system's functions.