Nokea
Thyroid hormone exerts its influence by ________.
- A. entering some cells and binding to intracellular receptors within the nuclei
- B. exerting only a minor effect on body metabolism
- C. causing a reduction in the number of blood vessel adrenergic receptors, and therefore decreasing blood pressure
- D. acting to decrease basal metabolic rate
Correct Answer: A
Rationale: The correct answer is A because thyroid hormone is a lipid-soluble hormone that can diffuse across the cell membrane and bind to intracellular receptors within the nuclei. This binding activates gene transcription, leading to various metabolic effects. Choice B is incorrect because thyroid hormone actually has a significant impact on body metabolism. Choice C is incorrect as thyroid hormone does not directly affect blood vessel adrenergic receptors or blood pressure. Choice D is incorrect as thyroid hormone actually acts to increase basal metabolic rate, not decrease it.
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The secretion of parathyroid hormone is a good example of __________.
- A. pituitary gland stimuli
- B. humoral stimuli
- C. neural stimuli
- D. hormonal stimuli
Correct Answer: B
Rationale: The correct answer is B: humoral stimuli. Parathyroid hormone secretion is regulated by the concentration of calcium in the blood, which is an example of humoral stimuli. When blood calcium levels decrease, parathyroid hormone is released to increase calcium levels. Pituitary gland stimuli (A), neural stimuli (C), and hormonal stimuli (D) are not directly involved in the regulation of parathyroid hormone secretion.
Which gland secretes two hormones, one that elevates blood glucose levels and another that decreases blood glucose levels?
- A. Pancreas
- B. Adenohypophysis
- C. Thyroid
- D. Adrenal cortex
Correct Answer: A
Rationale: The correct answer is A: Pancreas. The pancreas secretes insulin to decrease blood glucose levels and glucagon to elevate blood glucose levels. Insulin helps cells absorb glucose for energy, while glucagon triggers the release of stored glucose into the bloodstream. Adenohypophysis (B) secretes various hormones but not related to blood glucose regulation. Thyroid (C) secretes hormones that regulate metabolism, not directly impacting blood glucose levels. Adrenal cortex (D) secretes hormones like cortisol and aldosterone, which are not primarily involved in blood glucose regulation.
Adrenaline is contraindicated in:
- A. Cardiac arrest
- B. Acute bronchial asthma
- C. Anaphylactic shock
- D. Hypertension
Correct Answer: D
Rationale: Adrenaline is contraindicated in hypertension because it can worsen high blood pressure and increase the risk of cardiovascular events. Adrenaline's vasoconstrictive effects can further elevate blood pressure in individuals with hypertension, potentially leading to severe complications. Therefore, it is crucial to avoid administering adrenaline in patients with hypertension to prevent adverse cardiovascular outcomes.
Summary:
- A: Adrenaline is indicated in cardiac arrest to improve cardiac output.
- B: Adrenaline is indicated in acute bronchial asthma to relax bronchial smooth muscles.
- C: Adrenaline is indicated in anaphylactic shock to reverse severe allergic reactions.
- D (Correct): Adrenaline is contraindicated in hypertension due to its vasoconstrictive effects.
Atropine has the following pharmacological effects EXCEPT:
- A. It increases the heart rate
- B. Stimulates the respiratory center
- C. Has a mydriatic effect
- D. Produces bronchoconstriction
Correct Answer: D
Rationale: The correct answer is D: Atropine does not produce bronchoconstriction. Atropine is an anticholinergic drug that blocks the action of acetylcholine, leading to increased heart rate (A), stimulation of the respiratory center (B), and mydriatic effect (C). Bronchoconstriction is not a pharmacological effect of atropine because it actually helps dilate the bronchi, making it a useful treatment in cases of bronchospasm.
Which of the following hormones exerts negative feedback control on the secretion of ACTH?
- A. PTH
- B. Glucagon
- C. Cortisol
- D. Corticotrophin-releasing hormone
Correct Answer: C
Rationale: The correct answer is C: Cortisol. Cortisol exerts negative feedback control on the secretion of ACTH by inhibiting the release of corticotrophin-releasing hormone (CRH) and ACTH from the hypothalamus and pituitary gland, respectively. This feedback loop helps regulate the body's stress response and maintain hormone levels within a normal range.
A: PTH (Parathyroid Hormone) does not directly regulate the secretion of ACTH.
B: Glucagon regulates blood sugar levels and does not directly affect ACTH secretion.
D: Corticotrophin-releasing hormone (CRH) is the hormone that stimulates the release of ACTH, so it does not exert negative feedback control on ACTH secretion.