Nokea
The binding of a steroid hormone to its receptor would lead to the __________.
- A. transcription of the DNA for the gene that is 'turned on' by this event
- B. direct activation of second-messenger agents in the cell
- C. direct activation of enzymes in the cell
- D. formation of cAMP
Correct Answer: A
Rationale: The correct answer is A because the binding of a steroid hormone to its receptor triggers a series of events that ultimately lead to the transcription of DNA for the gene that is 'turned on'. This process involves the hormone-receptor complex entering the nucleus, binding to specific DNA sequences, recruiting transcription factors, and initiating gene expression.
Choice B is incorrect because steroid hormones do not typically use second messengers for signaling. Choice C is incorrect because while some hormones can activate enzymes indirectly, steroid hormones primarily act through gene transcription. Choice D is incorrect because cAMP is typically associated with signaling pathways involving non-steroid hormones like adrenaline.
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A patient presents with a bump on his neck. Upon taking a tissue sample, there appears to be parafollicular cells. The tumor is also associated with MEN II, although most of the time it is sporadic. What is the best way to moniter treatment?
- A. Measure Thyroid Hormone Levels
- B. Measure Iodine Levels
- C. Measure Tsh Levels
- D. Measure Calcitonin Levels
Correct Answer: D
Rationale: Rationale: The parafollicular cells in the tissue sample indicate a tumor of the thyroid gland, likely medullary thyroid carcinoma (MTC) associated with Multiple Endocrine Neoplasia Type II (MEN II). MTC primarily secretes calcitonin. Monitoring Calcitonin levels is crucial for assessing disease progression and treatment response in MTC. Measuring Thyroid Hormone Levels (A) would not be specific for MTC. Iodine Levels (B) are not relevant in this context. TSH Levels (C) reflect pituitary feedback and are not specific to MTC. Therefore, the best way to monitor treatment in this case is to measure Calcitonin Levels (D).
Selective beta2 stimulants frequently cause:
- A. Skeletal muscle tremors
- B. Tolerance
- C. Tachycardia
- D. All of the above
Correct Answer: D
Rationale: Selective beta2 stimulants typically cause skeletal muscle tremors due to their action on beta2 receptors in skeletal muscles. They can also lead to tolerance with prolonged use, requiring higher doses for the same effect. Additionally, they can cause tachycardia by stimulating beta2 receptors in the heart. Therefore, all of the above choices (A, B, and C) are correct.
Which if the following gland which can be classified as an endocrine and an exocrine gland?
- A. Thyroid.
- B. Thymus.
- C. Pancreas.
- D. Pituitary.
Correct Answer: C
Rationale: The correct answer is C: Pancreas. The pancreas is both an endocrine and exocrine gland. It secretes hormones like insulin and glucagon (endocrine function) into the bloodstream to regulate blood sugar levels, while also producing digestive enzymes (exocrine function) that are released into the small intestine to aid in digestion. The other choices are incorrect because:
A: Thyroid - primarily an endocrine gland that produces hormones like thyroxine.
B: Thymus - strictly an endocrine gland responsible for T-cell development.
D: Pituitary - also an endocrine gland that controls various other endocrine glands in the body.
Steatorrhoea occurs with all of the following EXCEPT:
- A. gastrinoma
- B. congenital defect in gastric lipase
- C. ileal disease with failure to reabsorb bile salts
- D. exocrine pancreatic disease
Correct Answer: B
Rationale: The correct answer is B because a congenital defect in gastric lipase would not lead to steatorrhoea. Gastrinoma, ileal disease with failure to reabsorb bile salts, and exocrine pancreatic disease can all cause steatorrhoea due to impaired fat digestion or absorption. Gastrinoma can lead to excessive acid production, which can interfere with fat digestion. Ileal disease can affect the reabsorption of bile salts necessary for fat digestion. Exocrine pancreatic disease can result in insufficient pancreatic enzymes needed for fat digestion. Therefore, choice B is the exception as it does not directly impact fat digestion or absorption.
The term catecholamine best describes drugs that are:
- A. Adrenergic receptor blockers
- B. Atropine-like in terms of their mechanisms and sites of action
- C. Classified like neostigmine and physostigmine
- D. Similar to adrenaline and noradrenaline in terms of structure and major pharmacologic properties
Correct Answer: D
Rationale: The correct answer is D because catecholamines are structurally similar to adrenaline and noradrenaline, sharing a catechol nucleus and amine group. This similarity allows them to exert similar pharmacologic effects such as increasing heart rate and blood pressure. Adrenergic receptor blockers (A) inhibit the action of catecholamines, atropine-like drugs (B) block muscarinic receptors, and neostigmine and physostigmine (C) are cholinesterase inhibitors, not catecholamines.