Endocrinology Exam Questions

Correct Answer: D

Rationale: Aldosterone is a hormone produced in the zona glomerulosa of the adrenal cortex, not the zona fasciculata (Choice A is incorrect). Conn's syndrome, also known as primary hyperaldosteronism, is characterized by excess aldosterone secretion, not a deficiency (Choice B is incorrect). Aldosterone production is under the control of the renin-angiotensin-aldosterone system, which is stimulated by factors such as low blood pressure, low blood volume, and high potassium levels. Elevated potassium in the blood directly suppresses aldosterone production by the adrenal glands, serving as a negative feedback mechanism to maintain electrolyte balance (Choice D is correct). The synthesis of aldosterone also requires cholesterol as the precursor, rather than pregnenolone (Choice E is incorrect). Lastly, aldosterone production is regulated in part by ACTH (adrenocorticotropic hormone), as it can enhance the effects of

Correct Answer: C

Rationale: Acromegaly is a disorder that is characterized by the overproduction of growth hormone (GH) by the pituitary gland in adults. This results in the abnormal growth of bones and tissues, leading to enlarged hands, feet, and facial features. The excess GH is usually caused by a pituitary tumor known as a somatotroph adenoma. This tumor causes the pituitary gland to produce excessive amounts of GH, which in turn leads to the symptoms associated with acromegaly. Treatment for acromegaly often involves surgical removal or reduction of the pituitary tumor, as well as medication to normalize GH levels.

Correct Answer: A

Rationale: Pseudo-Cushing's syndrome is a condition that mimics the symptoms of Cushing's syndrome but is not actually caused by excess cortisol production by the adrenal glands. It can be caused by various conditions such as chronic alcoholism, obesity, depression, and certain medications. However, myxoedema (also known as severe hypothyroidism) is not typically associated with pseudo-Cushing's syndrome. Myxoedema is characterized by low thyroid hormone levels, which would not lead to the symptoms of pseudo-Cushing's syndrome.

Correct Answer: A

Rationale: Oxytocin is a hormone produced by the hypothalamus and released by the pituitary gland. In the bloodstream, oxytocin is mostly bound to a carrier protein called neurophysin. This binding helps to protect oxytocin from being degraded too quickly in the bloodstream, thus allowing it to exert its effects on target tissues such as the uterus and mammary glands. Oxytocin plays important roles in stimulating uterine contractions during labor, facilitating milk letdown during breastfeeding, and promoting social bonding and emotional connections.

Correct Answer: B

Rationale: Myxoedema refers to severe hypothyroidism which can lead to neurological manifestations. The correct features associated with myxoedema include delayed relaxation of ankle jerk (Choice A), hypertonia (Choice C), and bradylalia (Choice D). Cerebellar ataxia, which involves incoordination and balance issues due to dysfunction of the cerebellum, is not a typical neurological feature seen in myxoedema.