Nokea
Which gland controls basal metabolic rate (BMR)?
- A. Parathyroid
- B. Pancreas
- C. Testes
- D. Thyroid
Correct Answer: D
Rationale: The correct answer is D: Thyroid. The thyroid gland produces hormones T3 and T4, which regulate the body's metabolism, including the basal metabolic rate (BMR). These hormones play a crucial role in controlling how the body uses energy. The other choices, A: Parathyroid, B: Pancreas, and C: Testes, do not directly regulate BMR. Parathyroid regulates calcium levels, pancreas regulates blood sugar levels, and testes produce hormones related to male reproductive functions. Thyroid is the only gland among the choices that specifically controls BMR through its hormone production.
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You are a resident in a hospital in a very poor part of the world. Their drug selection is limited. A patient presents with acute cardiac failure, for which your preferred drug is dobutamine, given intravenously. However, there is none available. Which of the following other drugs, or combination of drugs, would be a suitable alternative?
- A. Dopamine (at a very high dose)
- B. Ephedrine
- C. Ephedrine plus propranolol
- D. Norepinephrine plus phentolamine
Correct Answer: D
Rationale: The correct answer is D: Norepinephrine plus phentolamine. Norepinephrine is a potent vasopressor that can increase blood pressure and cardiac output in acute cardiac failure. Phentolamine is an alpha-blocker that can help counteract the vasoconstrictive effects of norepinephrine.
Rationale:
1. Norepinephrine: Increases blood pressure and cardiac output, improving perfusion to vital organs in acute cardiac failure.
2. Phentolamine: Counteracts the vasoconstrictive effects of norepinephrine, preventing excessive vasoconstriction.
Summary:
A: Dopamine at a very high dose may not be as effective as norepinephrine in acute cardiac failure.
B: Ephedrine is a less potent vasopressor compared to norepinephrine.
C: Ephedrine plus propranolol combination may lead to conflicting effects on blood pressure and heart rate
Regulating hormones from the hypothalamus ________.
- A. enter venous circulation and travel to the heart, which pumps the hormone-containing blood to the pituitary
- B. enter the hepatic portal system, which feeds the pituitary
- C. travel by arteries to the pituitary
- D. first enter into the hypophyseal portal system
Correct Answer: D
Rationale: The correct answer is D because hormones from the hypothalamus first enter the hypophyseal portal system before reaching the pituitary gland. This system allows direct communication between the hypothalamus and the pituitary gland, enabling precise control over hormone release. Choices A, B, and C are incorrect because they do not accurately describe the normal pathway of hormone regulation from the hypothalamus to the pituitary gland. Option A is incorrect as hormones do not travel to the heart before reaching the pituitary. Option B is incorrect because hormones do not enter the hepatic portal system to reach the pituitary. Option C is incorrect as hormones do not travel to the pituitary through arteries.
Cretinism, myxedema, and Graves’ disease are all:
- A. thyroid hormone deficiency diseases.
- B. thyroid hormone disorders caused by oversecretion of thyroxine.
- C. calcium imbalances due primarily to the lack of calcitonin.
- D. disorders of thyroid gland function.
Correct Answer: D
Rationale: Step 1: Cretinism, myxedema, and Graves' disease are all related to thyroid gland function.
Step 2: Cretinism is a congenital hypothyroidism, myxedema is adult hypothyroidism, and Graves' disease is hyperthyroidism.
Step 3: Thus, they are all disorders of thyroid gland function.
Summary:
- Choice A is incorrect because they are not all thyroid hormone deficiency diseases.
- Choice B is incorrect because they are not all caused by oversecretion of thyroxine.
- Choice C is incorrect because they are not primarily related to calcium imbalances due to lack of calcitonin.
Steroid hormones:
- A. require a second messenger.
- B. are secreted by the adrenal cortex.
- C. are secreted by the posterior pituitary.
- D. are secreted by the pancreas.
Correct Answer: B
Rationale: The correct answer is B: Steroid hormones are secreted by the adrenal cortex. The adrenal cortex is responsible for producing steroid hormones such as cortisol, aldosterone, and sex hormones. This is supported by the understanding of endocrine gland functions. Choices A, C, and D are incorrect because steroid hormones do not require a second messenger, are not secreted by the posterior pituitary, and are not secreted by the pancreas. Understanding the specific glands and their hormone production is crucial in selecting the correct answer.
Oxytocin ________.
- A. release is an example of a positive feedback control mechanism
- B. is an adenohypophyseal secretion
- C. exerts its most important effects during menstruation
- D. controls milk production
Correct Answer: A
Rationale: The correct answer is A because oxytocin release is an example of a positive feedback control mechanism. When oxytocin is released during childbirth, it stimulates contractions, which in turn lead to more oxytocin release, creating a positive feedback loop. This helps in the progression of labor.
Choice B is incorrect because oxytocin is a neurohypophyseal hormone, not an adenohypophyseal secretion. Choice C is incorrect as oxytocin's main effects are related to labor, delivery, and lactation, not menstruation. Choice D is incorrect because oxytocin primarily controls uterine contractions during labor and milk ejection during breastfeeding, not milk production itself.