Which of the following hormones are stored in the posterior pituitary gland?

Correct Answer:

Rationale: Oxytocin and Vasopressin, also known as antidiuretic hormone (ADH), are the hormones stored in the posterior pituitary gland. These hormones are produced by the hypothalamus and then transported and stored in the posterior pituitary gland until they are released into the bloodstream when needed. Oxytocin plays a role in uterine contractions during childbirth and milk ejection during lactation, while Vasopressin regulates water balance in the body by acting on the kidneys to reduce urine production and conserve water. The other hormones listed, such as Prolactin, TSH, GH, ACTH, FSH, and LH, are produced by the anterior pituitary gland.

Correct Answer: C

Rationale: The gold standard for diagnosing acromegaly is the oral glucose tolerance test (OGTT) along with growth hormone (GH) measurement. During this test, the patient is given a glucose solution to drink, and then blood samples are taken to measure GH levels at specific time intervals. In a person without acromegaly, glucose ingestion would typically suppress GH levels. However, in individuals with acromegaly, GH levels remain elevated even after glucose administration due to the inability of glucose to inhibit GH release from the tumor.

Correct Answer: B

Rationale: Diabetes Insipidus is a condition characterized by the body's inability to properly regulate water balance, leading to excessive urination and extreme thirst. This disorder is caused by a deficiency of vasopressin, also known as antidiuretic hormone (ADH). Vasopressin is a hormone produced by the hypothalamus and released by the pituitary gland to help regulate water balance in the body by controlling the amount of water reabsorbed by the kidneys. The lack of vasopressin in Diabetes Insipidus results in the kidneys producing a large volume of dilute urine, leading to dehydration and electrolyte imbalances.

Correct Answer: B

Rationale: Conn's syndrome, also known as primary hyperaldosteronism, is characterized by excess production of aldosterone by the adrenal glands. This leads to increased sodium retention and potassium excretion in the kidneys. As a result, patients with Conn's syndrome typically present with hypokalemia (low potassium levels), not hyperkalemia (high potassium levels). The other features of Conn's syndrome include alkalosis (metabolic), muscle cramps, and severe systemic hypertension.

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: 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.

Correct Answer: A

Rationale: Thyroid-stimulating hormone (TSH) is a glycoprotein hormone that is produced and secreted by the anterior pituitary gland. It acts on the thyroid gland to stimulate the production and release of thyroid hormones, T3 (triiodothyronine) and T4 (thyroxine). TSH plays a crucial role in regulating the function of the thyroid gland and maintaining overall thyroid hormone levels in the body.

Correct Answer: A

Rationale: Addison's disease, also known as primary adrenal insufficiency, is a condition where the adrenal glands do not produce enough steroid hormones, mainly cortisol and sometimes aldosterone. This deficiency in steroid hormone production is typically caused by autoimmune destruction of the adrenal cortex. Without enough cortisol and aldosterone, various symptoms may arise, such as fatigue, weight loss, low blood pressure, and skin discoloration. Therefore, option A accurately describes the nature of Addison's disease.

Correct Answer: D

Rationale: Vanillylmandelic acid (VMA) is a metabolite of catecholamines, such as epinephrine and norepinephrine. Phaeochromocytoma is a catecholamine-secreting tumor that arises from the chromaffin cells in the adrenal medulla or sympathetic ganglia. As a result of the increased production of catecholamines in patients with phaeochromocytoma, there is an increase in VMA excretion in the urine. This increase in VMA excretion is a significant diagnostic feature of phaeochromocytoma and helps in its detection through urine testing. Therefore, the correct choice is D. Phaeochromocytoma.