Catecholamines:

Correct Answer: D

Rationale: Rationale for Correct Answer D: Catecholamines include epinephrine and norepinephrine. These hormones are produced by the adrenal medulla in response to stress and play a crucial role in the fight-or-flight response. Epinephrine increases heart rate and blood flow to muscles, while norepinephrine helps maintain blood pressure. These actions help the body respond to stressful situations. Summary of Other Choices: A: Incorrect. Cortisol, aldosterone, and testosterone are not catecholamines. They are steroid hormones produced by the adrenal cortex. B: Incorrect. Adrenal cortex secretes cortisol and aldosterone, not catecholamines. C: Incorrect. Catecholamines actually increase plasma glucose levels to provide energy during stress.

Correct Answer: C

Rationale: The correct answer is C: Pineal gland. The pineal gland is responsible for secreting melatonin, a hormone that regulates our biological rhythms such as sleep-wake cycles. This gland is located in the brain and plays a crucial role in maintaining our circadian rhythm. The other choices are incorrect because: A: The pancreas secretes insulin and glucagon to regulate blood sugar levels, not melatonin. B: The adenohypophysis, or anterior pituitary gland, secretes various hormones but not melatonin. D: The adrenal gland produces hormones like cortisol and adrenaline, not melatonin.

Correct Answer: D

Rationale: The correct answer is D: polyphagia. Polyphagia is the medical term for excessive eating despite adequate glucose levels in the blood, commonly seen in conditions like diabetes mellitus. This excessive hunger is due to the body's inability to use glucose effectively, leading to a constant feeling of hunger. A: Acidosis refers to an excess of acid in the blood, not related to excessive eating. B: Polyuria is excessive urination, not directly related to excessive eating. C: Polydipsia is excessive thirst, also not directly related to excessive eating. In summary, polyphagia is the correct term for excessive eating despite adequate glucose levels, while the other choices are unrelated to this specific symptom.

Correct Answer: C

Rationale: The correct answer is C: raise blood glucose levels. Glucagon, growth hormone, cortisol, and epinephrine all work together to increase blood glucose levels through various mechanisms. Glucagon stimulates the breakdown of glycogen into glucose, growth hormone promotes gluconeogenesis, cortisol increases blood sugar through gluconeogenesis and inhibiting glucose uptake, and epinephrine triggers glycogen breakdown and inhibits insulin release. Choices A, B, and D are incorrect because not all of these hormones are secreted by the adrenal gland, they do not directly expand blood volume, and they do not stimulate osteoclastic activity, respectively.

Correct Answer: B

Rationale: The correct answer is B: PTH. Parathyroid hormone (PTH) regulates calcium levels in the body by acting on bones, kidneys, and intestine. PTH stimulates release of calcium from bones, reabsorption of calcium in kidneys, and absorption of calcium in the intestine. T3 and T4 are thyroid hormones that do not directly regulate calcium levels. ACTH is adrenocorticotropic hormone that stimulates the adrenal glands. Oxytocin is a hormone involved in labor and lactation, not calcium regulation.