Nokea
Injecting cocaine may cause a hypertensive crisis or stroke, and if the cocaine is inhaled frequently, it may destroy the tissues in the nose. Which of the following best describes how cocaine causes these adverse effects?
- A. Blocks alpha adrenergic receptors
- B. Blocks muscarinic receptors for ACh
- C. Blocks reuptake of noradrenaline released from adrenergic nerves
- D. Depletes norepinephrine from adrenergic nerve endings
Correct Answer: C
Rationale: Cocaine blocks the reuptake of noradrenaline from adrenergic nerves, leading to excessive stimulation of adrenergic receptors. This causes increased blood pressure, which can result in a hypertensive crisis or stroke. Additionally, the vasoconstrictive effects of excess noradrenaline can lead to tissue damage in the nose when cocaine is inhaled frequently. Choices A and B are incorrect because cocaine does not directly block alpha adrenergic or muscarinic receptors. Choice D is incorrect because cocaine does not deplete norepinephrine from adrenergic nerve endings but rather increases its concentration by blocking reuptake.
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Which of the following is NOT true of glucagon?
- A. produced by the pancreas
- B. increases blood glucose levels
- C. promotes the use of fat and protein instead of glucose
- D. stimulates the liver to store glucose as glycogen
Correct Answer: D
Rationale: The correct answer is D because glucagon actually stimulates the liver to release glucose into the bloodstream, not store glucose as glycogen. Glucagon helps increase blood glucose levels by promoting the breakdown of glycogen into glucose, and it also promotes the use of fat and protein for energy when glucose levels are low. Choices A, B, and C are all true statements about glucagon, making them incorrect options in this context.
Abrupt, sudden withdrawal of prednisone (cortisol) is most likely to cause:
- A. Cushing syndrome.
- B. hypocalcemic tetany.
- C. diabetes insipidus.
- D. acute adrenal insufficiency.
Correct Answer: D
Rationale: The correct answer is D: acute adrenal insufficiency. Abrupt withdrawal of prednisone can lead to adrenal insufficiency due to suppression of the adrenal glands' natural cortisol production. This can result in symptoms such as fatigue, weakness, abdominal pain, and low blood pressure. Cushing syndrome (choice A) is caused by excessive cortisol, hypocalcemic tetany (choice B) is due to low calcium levels, and diabetes insipidus (choice C) is a disorder of water balance regulation, not related to prednisone withdrawal.
Hormones often cause a cell to elicit multiple responses; this is because ________.
- A. there are thousands of receptors on the cell membrane
- B. the receptors bind to several hormones at the same time
- C. the protein kinases are rapidly metabolized
- D. during protein kinase activation, enzymes phosphorylate many other enzymes
Correct Answer: D
Rationale: The correct answer is D because during protein kinase activation, enzymes phosphorylate many other enzymes, leading to a cascade of signaling events that can trigger multiple responses in a cell. This process amplifies and diversifies the cellular response to hormones.
A: Choice A is incorrect because the number of receptors on the cell membrane does not directly relate to the ability of hormones to elicit multiple responses.
B: Choice B is incorrect because receptors typically bind to one hormone molecule at a time, not multiple hormones simultaneously.
C: Choice C is incorrect because the rapid metabolism of protein kinases does not directly explain why hormones can elicit multiple responses in a cell.
Which of the following is not a similarity between hormones and neurotransmitters?
- A. NONE OF THE ABOVE (all of the above are similarities between hormones and neurotransmitters)
- B. Both are chemical messengers.
- C. Both can sometimes be chemically identical.
- D. Both produce molecules that act on receptors.
Correct Answer: A
Rationale: The correct answer is A because it states that none of the above choices are similarities between hormones and neurotransmitters. This is accurate as choices B, C, and D all highlight similarities between hormones and neurotransmitters. Choice B is correct as both are chemical messengers, choice C is correct because some hormones and neurotransmitters can be chemically identical, and choice D is correct because both produce molecules that act on receptors. Therefore, A is the correct choice as it states that there are no similarities between the two, which is not the case.
Which of the following glands disappears during old age?
- A. Thymus
- B. Parathyroid
- C. Thyroid
- D. Pituitary
Correct Answer: A
Rationale: The thymus gland is the correct answer because it involutes or shrinks with age, leading to decreased immune function. The parathyroid, thyroid, and pituitary glands do not disappear with old age but may undergo changes in function. The parathyroid regulates calcium levels, the thyroid controls metabolism, and the pituitary gland secretes various hormones. Therefore, the thymus gland is the only gland that disappears during old age, making it the correct answer.