Endocrinology Exam Questions and Answers

Correct Answer: A

Rationale: Cushing's syndrome is a condition characterized by excessive levels of cortisol in the body. Cortisol is a hormone produced by the adrenal glands that helps regulate various bodily functions, including metabolism, immune response, and stress response. When there is an overproduction of cortisol, either due to excessive production by the adrenal glands or prolonged use of corticosteroid medications, it can result in Cushing's syndrome. Symptoms of Cushing's syndrome include weight gain, particularly in the face and abdomen, high blood pressure, muscle weakness, and irregularities in menstruation. It is important to diagnose and manage Cushing's syndrome to prevent potential complications such as diabetes, osteoporosis, and cardiovascular disease.

Correct Answer: A

Rationale: Hypertonicity (increased osmolarity or high concentration of solutes in the blood) is the most potent stimulus for the hypothalamic production of arginine vasopressin (also known as antidiuretic hormone or ADH). When the body senses increased plasma osmolality, the osmoreceptors in the hypothalamus stimulate the release of vasopressin from the posterior pituitary gland. Vasopressin acts on the kidneys to increase water reabsorption and decrease urine output, helping to restore normal osmolarity. This mechanism helps to conserve water and maintain body fluid balance in response to dehydration or increased solute concentration in the blood.

Correct Answer: A

Rationale: Cushing's syndrome is a condition characterized by excessive levels of cortisol in the body. Cortisol is a hormone produced by the adrenal glands that helps regulate various bodily functions, including metabolism, immune response, and stress response. When there is an overproduction of cortisol, either due to excessive production by the adrenal glands or prolonged use of corticosteroid medications, it can result in Cushing's syndrome. Symptoms of Cushing's syndrome include weight gain, particularly in the face and abdomen, high blood pressure, muscle weakness, and irregularities in menstruation. It is important to diagnose and manage Cushing's syndrome to prevent potential complications such as diabetes, osteoporosis, and cardiovascular disease.

Correct Answer: B

Rationale: ADH (antidiuretic hormone), also known as vasopressin, is secreted by the posterior lobe of the pituitary gland. ADH plays a key role in regulating water balance in the body by controlling the reabsorption of water in the kidneys. When the body senses a decrease in blood volume or an increase in blood osmolarity, ADH is released to signal the kidneys to conserve water, leading to concentrated urine production and water retention in the body.

Correct Answer: A

Rationale: Phaeochromocytoma is a neuroendocrine tumor that arises from the chromaffin cells of the adrenal medulla. It is the most common cause of a catecholamine-secreting tumor in adults. While it can also rarely occur outside the adrenal gland (referred to as extra-adrenal or paraganglioma), the majority of cases originate within the adrenal medulla. Symptoms of phaeochromocytoma are due to the excessive release of catecholamines (epinephrine and norepinephrine), leading to a characteristic triad of headaches, sweating, and palpitations. Therefore, the commonest cause of phaeochromocytoma is a tumor of the adrenal medulla.