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: B

Rationale: Cushing's syndrome is a disorder caused by prolonged exposure to high levels of cortisol hormone. While Cushing's syndrome can manifest with a variety of symptoms, peripheral neuropathy is not a typical feature of this condition. Cushing's syndrome is commonly associated with symptoms such as hirsutism (excessive hair growth), purple striae (skin stretch marks that are purple in color), and acne due to the hormonal imbalances it creates. Peripheral neuropathy, which involves damage to the peripheral nerves leading to symptoms like numbness, tingling, and weakness in the extremities, is not a characteristic symptom of Cushing's syndrome.

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: C

Rationale: Growth hormone deficiency (GHD) is commonly associated with decreased bone mineral density, leading to an increased risk of fractures and osteoporosis. Therefore, increased bone mineral density would not typically be a sign or symptom of GHD. On the other hand, abnormal lipid profile, atherosclerosis, and left ventricular dysfunction are all potential signs or symptoms of GHD. Abnormal lipid profile can manifest as increased levels of LDL cholesterol and decreased levels of HDL cholesterol. Atherosclerosis, the buildup of plaque in the arteries, can occur in individuals with GHD due to the impact on lipid metabolism. Left ventricular dysfunction may also be seen in individuals with GHD due to the role of growth hormone in cardiac function and structure.

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.