All of the following are β-adrenergic agonists EXCEPT:
- A. Adrenaline
- B. Dopamine
- C. Noradrenaline
- D. Phenylephrine
Correct Answer: D
Rationale: The correct answer is D: Phenylephrine. Beta-adrenergic agonists stimulate beta-adrenergic receptors. Phenylephrine is an alpha-adrenergic agonist, not a beta-adrenergic agonist. Adrenaline, dopamine, and noradrenaline are all beta-adrenergic agonists. Therefore, the correct answer is D.
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Which of the following statements regarding hormones is incorrect?
- A. Hormones and neurotransmitters require a synapse in order to communicate information to other cells and tissues.
- B. Only cells that have receptors to a certain hormone may be affected by that hormone.
- C. Hormones can cause target cells to alter patterns of gene expression, producing proteins in different quantities
- D. G proteins and cAMP are second messengers that serve to enhance or amplify the hormonal effect.
Correct Answer: a
Rationale: The correct answer is A because hormones and neurotransmitters do not require a synapse to communicate with other cells. Hormones are typically released into the bloodstream and travel throughout the body to target cells with specific receptors. Neurotransmitters, on the other hand, communicate across synapses between nerve cells. Choice B is correct as hormones only affect cells with specific receptors. Choice C is correct as hormones can indeed influence gene expression in target cells. Choice D is correct as G proteins and cAMP are common second messengers that help transmit the hormonal signal within the cell.
Propranolol is contraindicated in:
- A. Angina pectoris
- B. Bronchial asthma
- C. Hypertension
- D. Arrhythmia
Correct Answer: B
Rationale: Propranolol is a non-selective beta-blocker that can cause bronchoconstriction, making it contraindicated in bronchial asthma. It can worsen asthma symptoms by blocking beta-2 receptors in the lungs. Angina pectoris, hypertension, and arrhythmia are conditions where propranolol is commonly used due to its beta-blocking effects on the heart and blood vessels.
Like the small intestine, the large intestine has villi to aid absorption?
- A. TRUE
- B. FALSE
Correct Answer: B
Rationale: The correct answer is B: FALSE. The large intestine does not have villi like the small intestine. Villi are finger-like projections in the small intestine that increase surface area for nutrient absorption. The large intestine primarily absorbs water and electrolytes, and does not have villi. Other choices are incorrect because the large intestine does not have villi and does not aid in absorption like the small intestine.
Gonadocorticoid(s) ________.
- A. synthesized by the adrenal medulla are primarily androgens
- B. production by the adrenal gland is insignificant compared with sex hormone release from the gonads during late puberty
- C. secretion inhibition is highly dependent on a negative feedback loop involving ACTH
- D. hypersecretion can result in adrenogenital syndrome, also called feminization
Correct Answer: B
Rationale: The correct answer is B because during late puberty, the production of sex hormones by the gonads significantly outweighs the production of gonadocorticoids by the adrenal gland. This is due to the maturation and increased activity of the gonads during this developmental stage.
Rationale:
A: Synthesized by the adrenal medulla are primarily catecholamines, not androgens.
C: Secretion inhibition of gonadocorticoids is primarily regulated by the renin-angiotensin-aldosterone system, not solely by a negative feedback loop involving ACTH.
D: Hypersecretion of gonadocorticoids can lead to conditions like Cushing's syndrome, not adrenogenital syndrome or feminization.
Calcium level in the blood is regulated by hormones released from the .
- A. testes
- B. adrenal medulla and pancreas
- C. parathyroid and thymus
- D. parathyroid and thyroid
Correct Answer: D
Rationale: The correct answer is D because calcium regulation in the blood is primarily controlled by hormones released from the parathyroid and thyroid glands. Parathyroid hormone (PTH) released by the parathyroid glands increases blood calcium levels, while calcitonin released by the thyroid gland decreases blood calcium levels. The other choices are incorrect because the testes primarily produce hormones related to reproduction (not calcium regulation), the adrenal medulla and pancreas are not directly involved in calcium regulation, and the thymus is involved in immune function but not in calcium regulation.