Nokea
Melatonin from the pineal gland regulates ____.
- A. sleep-wake cycles.
- B. water balance.
- C. sexual development.
- D. Both A and C
Correct Answer: D
Rationale: The correct answer is D, Both A and C. Melatonin from the pineal gland regulates sleep-wake cycles (A) by influencing the body's internal clock. It also plays a role in sexual development (C) by influencing the release of reproductive hormones. Other choices, B (water balance), are regulated by hormones like ADH and aldosterone, not melatonin. The correct answer encompasses the functions of melatonin in both sleep regulation and sexual development.
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Which of the following suppress(es) the secretion of ACTH?
- A. Elevated blood glucose levels
- B. Dietary iodine
- C. Corticotropin-releasing hormone (CRH)
- D. Elevated plasma cortisol levels
Correct Answer: D
Rationale: Elevated plasma cortisol levels suppress the secretion of ACTH through negative feedback. High cortisol levels signal the hypothalamus and pituitary to decrease the release of CRH and ACTH, respectively, to maintain homeostasis. This is a regulatory mechanism to prevent excessive cortisol production.
A: Elevated blood glucose levels do not directly suppress ACTH secretion.
B: Dietary iodine is not related to ACTH secretion.
C: CRH stimulates ACTH release, so it does not suppress its secretion.
The stimulus for producing insulin is __________.
- A. low blood amino acid concentration
- B. low blood glucose concentration
- C. low blood fatty acid concentration
- D. high blood glucose concentration
Correct Answer: D
Rationale: The correct answer is D: high blood glucose concentration. Insulin is released by the pancreas in response to increased blood glucose levels. High blood glucose signals the body to lower it by facilitating the uptake of glucose into cells. Low blood amino acid, fatty acid, or glucose concentrations would not stimulate insulin release as they do not directly regulate blood sugar levels.
Gonadocorticoid(s) ________.
- A. synthesized by the adrenal medulla are primarily androgens
- B. production by the adrenal gland is insignificant compared with sex hormone release from the gonads during late puberty
- C. secretion inhibition is highly dependent on a negative feedback loop involving ACTH
- D. hypersecretion can result in adrenogenital syndrome, also called feminization
Correct Answer: B
Rationale: The correct answer is B because during late puberty, the production of sex hormones by the gonads significantly outweighs the production of gonadocorticoids by the adrenal gland. This is due to the maturation and increased activity of the gonads during this developmental stage.
Rationale:
A: Synthesized by the adrenal medulla are primarily catecholamines, not androgens.
C: Secretion inhibition of gonadocorticoids is primarily regulated by the renin-angiotensin-aldosterone system, not solely by a negative feedback loop involving ACTH.
D: Hypersecretion of gonadocorticoids can lead to conditions like Cushing's syndrome, not adrenogenital syndrome or feminization.
The endocrine gland(s) referred to as the 'master gland' is the:
- A. pancreas
- B. adrenal glands
- C. thyroid gland
- D. pituitary gland
Correct Answer: D
Rationale: The correct answer is D: pituitary gland. The pituitary gland is often referred to as the 'master gland' because it controls the functions of other endocrine glands in the body. It secretes hormones that regulate various bodily functions such as growth, metabolism, and reproduction. It is located at the base of the brain and is divided into two parts: anterior and posterior. The anterior pituitary gland produces and releases several important hormones that influence other endocrine glands. The other choices (A: pancreas, B: adrenal glands, C: thyroid gland) do not have the same broad regulatory control over the endocrine system as the pituitary gland.
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: congenital defect in gastric lipase. Steatorrhoea is the presence of excess fat in the stool due to malabsorption. Gastrinoma (A), ileal disease (C), and exocrine pancreatic disease (D) can all lead to malabsorption of fats resulting in steatorrhoea. However, a congenital defect in gastric lipase does not directly affect fat absorption in the intestines, making it the exception in this scenario.