Nokea
Virtually all of the protein or amino acid-based hormones exert their effects through intracellular ________.
- A. ions
- B. deactivators
- C. nucleotides
- D. second messengers
Correct Answer: D
Rationale: The correct answer is D: second messengers. Protein or amino acid-based hormones are unable to pass through the cell membrane due to their large size and hydrophilic nature. Therefore, they bind to specific receptors on the cell surface, triggering a series of events that lead to the production of second messengers inside the cell. These second messengers, such as cyclic AMP or calcium ions, then transmit the hormonal signal to the target cell's interior to initiate a physiological response. Choices A, B, and C are incorrect because protein or amino acid-based hormones do not directly exert their effects through ions, deactivators, or nucleotides intracellularly.
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Which of the following is true of both prolactin and oxytocin? Both
- A. are concerned with lactation.
- B. are secreted by the adenohypophysis.
- C. stimulate the mammary glands to make milk.
- D. are concerned only with lactation.
Correct Answer: A
Rationale: The correct answer is A: are concerned with lactation. Both prolactin and oxytocin are hormones involved in lactation. Prolactin promotes milk production in the mammary glands, while oxytocin stimulates the release of milk from the breasts during breastfeeding. Therefore, both hormones play crucial roles in the lactation process.
Choice B is incorrect because oxytocin is secreted by the posterior pituitary gland, not the adenohypophysis. Choice C is incorrect because oxytocin specifically stimulates the contraction of the muscles around the mammary glands to release milk, not the production of milk. Choice D is incorrect because oxytocin is also involved in milk ejection, not just lactation itself.
Pilocarpine is used in the treatment of:
- A. Increased salivary secretion
- B. Glaucoma
- C. Intestinal colic
- D. Cardiac arrhythmias
Correct Answer: B
Rationale: The correct answer is B: Glaucoma. Pilocarpine is a cholinergic agonist that works by causing constriction of the pupil and increasing the outflow of aqueous humor in the eye, thereby reducing intraocular pressure in glaucoma. Increased salivary secretion (A) is a side effect of pilocarpine use. Pilocarpine is not indicated for treating intestinal colic (C) or cardiac arrhythmias (D).
Peptide hormones _______________.
- A. are hydrophilic
- B. cannot enter the target cell
- C. bind to a receptor on the cell surface
- D. all of these
Correct Answer: D
Rationale: The correct answer is D because peptide hormones are hydrophilic molecules that cannot pass through the cell membrane, so they bind to receptors on the cell surface to initiate signaling pathways within the cell. Therefore, they are unable to enter the target cell like lipid-soluble hormones do. By binding to specific receptors on the cell surface, peptide hormones trigger a series of events that ultimately lead to a cellular response. Therefore, all of the given statements are true, making D the correct choice.
Which one of the following drugs can trigger severe bronchospasm in a patient who has asthma?
- A. Atropine
- B. Isoproterenol
- C. Phenylephrine
- D. Propranolol
Correct Answer: D
Rationale: The correct answer is D: Propranolol. Propranolol is a non-selective beta-blocker that can trigger severe bronchospasm in patients with asthma by blocking beta-2 receptors in the lungs, leading to bronchoconstriction. Atropine (A) is an anticholinergic drug that dilates the airways. Isoproterenol (B) is a beta-agonist that relaxes the airway smooth muscles. Phenylephrine (C) is a sympathomimetic drug that constricts blood vessels, not airways.
Which of the following is NOT a function of hormones?
- A. Controlling reproduction
- B. Regulating mood
- C. NONE OF THE ABOVE (All of the above are functions of hormones)
- D. Influencing growth
Correct Answer: C
Rationale: Answer C is correct because all of the other choices are indeed functions of hormones.
A) Hormones play a crucial role in controlling reproduction by regulating the menstrual cycle, ovulation, and sperm production.
B) Hormones such as serotonin and dopamine have a direct impact on mood regulation and emotional well-being.
D) Hormones like growth hormone and thyroid hormones are essential in influencing growth and development.
Therefore, since all the other choices are valid functions of hormones, the correct answer is C, NONE OF THE ABOVE.