The hypersecretion of growth hormone leads to:

Correct Answer: C

Rationale: The correct answer is C: Acromegaly. Hypersecretion of growth hormone in adults leads to acromegaly, characterized by enlarged hands, feet, and facial features. This occurs due to excess GH after epiphyseal plate closure. A: Cretinism is caused by congenital hypothyroidism, not GH hypersecretion. B: Myxoedema is a severe form of hypothyroidism, not related to GH. D: Graves disease is an autoimmune disorder causing hyperthyroidism, not GH hypersecretion.

Correct Answer: C

Rationale: Homeostasis is the maintenance of a stable internal environment to support optimal physiological functioning. It involves mechanisms that regulate variables within a narrow range. Negative feedback is a key mechanism in maintaining homeostasis by counteracting deviations from set points. Positive feedback amplifies changes and is not involved in maintaining stability. Metabolism refers to the chemical processes in the body and is not specifically related to the maintenance of internal stability. Therefore, the correct answer is C (homeostasis) because it directly relates to the concept of maintaining a stable internal environment through regulatory mechanisms.

Correct Answer: A

Rationale: Step 1: Identify the symptoms described in the patient: Moon face, truncal obesity, hypertension, purple striae, buffalo hump, fragile skin, impaired glucose tolerance. Step 2: These symptoms are classic for Cushing's syndrome, which is caused by excess cortisol. Step 3: The opposite of increased cortisol levels is decreased cortisol levels. Step 4: Addison's disease is characterized by adrenal insufficiency, leading to decreased cortisol levels. Step 5: Therefore, the correct answer is A: Addison's disease. Summary: - B: Pheochromocytoma is a tumor of the adrenal medulla, causing excess catecholamines, not related to cortisol. - C: Hyperaldosteronism is excess aldosterone production, not related to cortisol. - D: Cushing's syndrome is characterized by excess cortisol, not the opposite.

Correct Answer: B

Rationale: The correct answer is B because peptide hormones are hydrophilic and cannot pass through the cell membrane. Therefore, their receptors must be located on the cell's outer membrane to bind and trigger intracellular signaling pathways. Option A is incorrect because hydrophobic hormones can directly pass through the cell membrane, so their receptors are typically inside the cell. Option C is incorrect because hydrophobic hormones do not require a receptor on the cell's outer membrane. Option D is incorrect because hydrophilic hormones, like peptide hormones, require receptors on the cell's outer membrane.

Correct Answer: A

Rationale: The correct answer is A: Parathyroid and thyroid. The parathyroid glands secrete parathyroid hormone, which increases blood calcium levels by promoting calcium release from bones and increasing calcium absorption in the intestines. The thyroid gland produces calcitonin, which lowers blood calcium levels by inhibiting bone breakdown and increasing calcium excretion by the kidneys. The adrenal medulla and pancreas do not play a direct role in regulating calcium levels. Testes are not involved in calcium regulation. The thymus is responsible for developing T-cells and does not have a role in calcium regulation.