Which of the following may indicate hypersecretion of thyroid hormone?

Correct Answer: A

Rationale: Weight loss is a common symptom of hyperthyroidism, which is characterized by an excess secretion of thyroid hormone. This increased metabolic rate can lead to weight loss despite normal or increased appetite. Bradycardia (slow heart rate), cold intolerance, and lethargy are more commonly associated with hypothyroidism, where there is an insufficient production of thyroid hormone. Therefore, choices B, C, and D are incorrect in the context of hypersecretion of thyroid hormone.

Correct Answer: A

Rationale: The correct answer is the Distal convoluted tubule (DCT). The DCT is the part of the nephron closest to the collecting duct, where the final adjustments to electrolyte and fluid balance are made. Bowman's Capsule is located at the beginning of the nephron, where filtration of blood occurs. The Afferent Arteriole brings blood to the glomerulus for filtration. The Proximal Convoluted Tubule (PCT) is situated after the Bowman's Capsule and is not the part closest to the collecting duct.

Correct Answer: D

Rationale: The correct answer is Parathyroid glands. The parathyroid glands are responsible for regulating calcium levels in the blood by secreting parathyroid hormone (PTH). PTH helps increase calcium levels in the blood when they are too low. The other glands listed, such as the Hypothalamus, Thyroid, and Pituitary glands, do not directly control calcium concentration in the blood.

Correct Answer: B

Rationale: The correct answer is the Medulla Oblongata. This part of the brain is responsible for regulating essential autonomic functions such as heart rate, respiratory rate, and blood pressure. The Corpus Callosum is responsible for connecting the left and right hemispheres of the brain, not for regulating these vital functions. The Pituitary Glands and Pineal Glands are part of the endocrine system and are not directly involved in regulating heart rate, respiratory rate, and blood pressure.

Correct Answer: C

Rationale: The correct answer is C: Store and concentrate bile, a fluid produced by the liver that helps with fat digestion. The gallbladder stores bile produced by the liver and releases it to aid in the digestion of fats. Choice A is incorrect as the liver, not the gallbladder, filters blood and detoxifies harmful substances. Choice B is incorrect because the production of enzymes primarily occurs in the pancreas, not the gallbladder. Choice D is incorrect as the gallbladder's main role is not to further digest food but to store and release bile.