Nokea
Muscarinic receptors can be stimulated by the following drugs EXCEPT:
- A. Pilocarpine
- B. Hyoscine
- C. Acetylcholine
- D. Neostigmine
Correct Answer: B
Rationale: The correct answer is B: Hyoscine. Muscarinic receptors can be stimulated by Pilocarpine, Acetylcholine, and Neostigmine, as they are known agonists of muscarinic receptors. Hyoscine, also known as scopolamine, is an antagonist of muscarinic receptors, blocking their stimulation. This makes it the exception among the listed drugs.
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The main mineralocorticoid produced by the adrenal cortex is _____.
- A. cortisol.
- B. glucagon.
- C. epinephrine.
- D. aldosterone.
Correct Answer: D
Rationale: The correct answer is D: aldosterone. Aldosterone is the main mineralocorticoid produced by the adrenal cortex, responsible for regulating electrolyte balance and blood pressure. It acts on the kidneys to increase sodium reabsorption and potassium excretion. Cortisol (A) is a glucocorticoid, not a mineralocorticoid. Glucagon (B) is a hormone produced by the pancreas that raises blood glucose levels. Epinephrine (C) is a hormone produced by the adrenal medulla involved in the fight-or-flight response, not a mineralocorticoid. Therefore, the correct answer is aldosterone (D) due to its specific role in mineral balance regulation.
Chemical signals that affect the behavior of other glands and tissues are _____.
- A. enzymes.
- B. hormones.
- C. carbohydrates.
- D. metabolites.
Correct Answer: B
Rationale: The correct answer is B: hormones. Hormones are chemical signals produced by glands that travel through the bloodstream to affect the behavior of other glands and tissues. Enzymes (choice A) are catalysts for chemical reactions, not signaling molecules. Carbohydrates (choice C) are energy sources and structural components, not signaling molecules. Metabolites (choice D) are the byproducts of metabolism, not signaling molecules. Hormones are specifically designed to regulate physiological processes in the body by acting on target cells, making them the most fitting choice among the options provided.
Chief cells secrete:
- A. HCl
- B. pepsinogen
- C. intrinsic factor
- D. HCO3-
Correct Answer: B
Rationale: Chief cells in the stomach secrete pepsinogen, which is the inactive precursor of pepsin, an enzyme that helps break down proteins. This is the correct answer because pepsinogen is the primary product secreted by chief cells. HCl is secreted by parietal cells, intrinsic factor is secreted by parietal cells in the stomach, and HCO3- is secreted by the pancreas to neutralize stomach acid in the duodenum.
What gland requires iodine in order to produce its hormones?
- A. Adrenal cortex
- B. Pancreas
- C. Parathyroid glands
- D. Thyroid gland
Correct Answer: D
Rationale: The correct answer is D: Thyroid gland. The thyroid gland requires iodine to produce its hormones, such as thyroxine and triiodothyronine, which are essential for regulating metabolism, growth, and development. Iodine is a crucial component of these thyroid hormones. The other choices (A: Adrenal cortex, B: Pancreas, C: Parathyroid glands) do not require iodine for hormone production and are not involved in the synthesis of thyroid hormones. Therefore, the correct answer is the thyroid gland because it specifically relies on iodine for hormone synthesis, making it the only gland in the list that fits this criteria.
Which of the following is most responsive to treatment with thyroxine?
- A. Diabetes mellitus
- B. Hyperglycemia
- C. Myxedema
- D. Graves’ disease
Correct Answer: C
Rationale: Rationale:
1. Myxedema is caused by hypothyroidism, which can be effectively treated with thyroxine.
2. Thyroxine is a synthetic form of thyroid hormone that helps restore thyroid hormone levels.
3. Myxedema symptoms such as fatigue, weight gain, and cold intolerance improve with thyroxine treatment.
Summary of Incorrect Choices:
A. Diabetes mellitus and hyperglycemia are not directly related to thyroid hormone levels.
B. Hyperglycemia is not primarily treated with thyroxine.
D. Graves' disease is a thyroid disorder characterized by hyperthyroidism, which requires different treatments than hypothyroidism.