Which one of the following statements describes the underlying pathology of Grave's disease?

Correct Answer: A

Rationale: Graves' disease is an autoimmune disorder where autoantibodies, known as thyroid-stimulating immunoglobulins (TSIs) or thyroid-stimulating antibodies (TSAs), bind to and stimulate the thyroid-stimulating hormone (TSH) receptors on thyroid follicular cells. This leads to increased production and secretion of thyroid hormones T3 (triiodothyronine) and T4 (thyroxine), causing hyperthyroidism. The autoantibodies essentially mimic the action of TSH, resulting in excess thyroid hormone release and manifestation of hyperthyroid symptoms. This underlying pathology of Graves' disease is distinct from other causes of hyperthyroidism, making choice A the correct statement.

Correct Answer: D

Rationale: Neurogenic diabetes insipidus is due to a deficiency in vasopressin (antidiuretic hormone, ADH) production in the hypothalamus or a failure of proper vasopressin release from the posterior pituitary. Causes of neurogenic DI typically involve factors affecting vasopressin synthesis, storage, or release. However, mutations in the vasopressin gene itself would be a cause of genetic forms of diabetes insipidus, not neurogenic diabetes insipidus. Common causes of neurogenic diabetes insipidus include traumatic brain injury, brain tumors, pituitary adenomas, meningitis, and Sheehan's syndrome.

Correct Answer: D

Rationale: Follicle-stimulating hormone (FSH) is one of the hormones produced in the anterior pituitary gland. The anterior pituitary gland secretes several hormones that regulate various functions in the body. FSH plays a crucial role in both males and females. In females, FSH stimulates the growth and maturation of ovarian follicles, which contain the eggs. In males, FSH is essential for the production of sperm in the testes. The production and release of FSH are regulated by the hypothalamus and gonadotropin-releasing hormone (GnRH).

Correct Answer: C

Rationale: Acromegaly is a rare hormonal disorder where excess growth hormone is produced, leading to the enlargement of bones and tissues. The prevalence of acromegaly is higher in men compared to women, with a ratio of about two men affected for every woman. This gender difference is believed to be due to the impact of sex hormones on the development and progression of the condition. While acromegaly can affect both men and women, men are more commonly diagnosed with the disorder.

Correct Answer: B

Rationale: The adrenal cortex is the outer region of the adrenal glands and is responsible for producing several hormones, including aldosterone. Aldosterone is a mineralocorticoid hormone that plays a crucial role in regulating electrolyte balance, particularly sodium and potassium, in the body. It helps maintain blood pressure and fluid balance by acting on the kidneys to reabsorb sodium and water while excreting potassium in the urine. Adrenaline and noradrenaline (also known as epinephrine and norepinephrine) are produced by the adrenal medulla, which is the inner region of the adrenal glands. Cortisol is another hormone produced by the adrenal cortex, but aldosterone specifically regulates electrolyte balance.