T3 and T4:

Correct Answer: B

Rationale: Step-by-step rationale for why choice B is correct: 1. T3 and T4 are thyroid hormones produced by the thyroid gland. 2. These hormones play a crucial role in regulating the body's metabolism. 3. T3 and T4 directly influence the basal metabolic rate (BMR). 4. An increase in T3 and T4 levels leads to an increase in BMR. 5. Therefore, choice B is correct as T3 and T4 regulate the basal metabolic rate. Summary of why other choices are incorrect: - Choice A (stimulate the adenohypophysis to secrete TSH) is incorrect as TSH is produced by the pituitary gland, not affected by T3 and T4. - Choice C (stimulate osteoclastic activity, thereby elevating plasma calcium levels) is incorrect as this function is primarily attributed to parathyroid hormone, not T3 and T4. - Choice D (all is applicable) is incorrect as only choice B

Correct Answer: B

Rationale: The correct answer is B: He will develop an acute adrenal insufficiency. When a patient abruptly stops taking a large dose of prednisone after long-term use, it can suppress the body's natural production of cortisol. This sudden withdrawal can lead to adrenal insufficiency, a potentially life-threatening condition. The adrenal glands may not be able to produce enough cortisol to meet the body's needs, causing symptoms such as fatigue, weakness, low blood pressure, and even shock. This is a serious concern that requires medical attention. Incorrect choices: A: His arthritic pain will recur - While this is a valid concern, it is not the most serious issue compared to acute adrenal insufficiency. C: He will continue to exhibit symptoms of Cushing syndrome - Cushing syndrome is a result of prolonged exposure to high levels of cortisol, not sudden withdrawal. D: He will develop a moon face and buffalo hump - These are physical symptoms associated with Cushing syndrome, not acute adrenal

Correct Answer: C

Rationale: The correct answer is C: Pineal gland. The pineal gland is located in the brain and is often referred to as the "biological clock" due to its role in regulating the sleep-wake cycle through the secretion of melatonin. The posterior pituitary (choice A) is responsible for releasing hormones produced by the hypothalamus, not related to the circadian rhythm. The hypothalamus (choice B) is involved in regulating various physiological processes but is not directly associated with the circadian rhythm. The thymus (choice D) plays a role in the immune system, not in regulating the biological clock. Thus, the pineal gland is the correct answer as it specifically controls the circadian rhythm.

Correct Answer: A

Rationale: The correct answer is A: Thyroid. The thyroid gland produces thyroid hormones T3 and T4, which regulate the body's metabolic rate. These hormones control the basal metabolic rate (BMR) by influencing the rate at which cells use energy. The other choices, B: Parathyroid, C: Testes, and D: Pancreas, do not directly control BMR. Parathyroid regulates calcium levels, Testes produce hormones related to reproduction, and Pancreas regulates blood sugar levels through insulin and glucagon secretion. Thyroid is the only gland among the choices that specifically influences BMR.

Correct Answer: A

Rationale: The correct answer is A: sweat gland. Endocrine glands secrete hormones directly into the bloodstream, affecting distant target organs. Sweat glands, on the other hand, are exocrine glands that release sweat onto the skin surface to regulate body temperature. The adrenal glands, thyroid gland, and pituitary gland are all endocrine glands that secrete hormones, making them the correct choices. A sweat gland does not secrete hormones into the bloodstream, so it does not qualify as an endocrine gland.