Nokea
Anti-diuretic hormone secretion is:
- A. increased during stress.
- B. reduced during hemorrhage.
- C. reduced by increased blood osmolality.
- D. increased by alcohol.
Correct Answer: B
Rationale: Anti-diuretic hormone (ADH), also known as vasopressin, is a hormone released by the pituitary gland in response to changes in blood osmolality, blood volume, and blood pressure. During hemorrhage (significant blood loss), the body experiences a decrease in blood volume and blood pressure. In response to this decrease in blood volume, ADH secretion is increased to help the body retain water and maintain blood pressure levels. Therefore, it is incorrect to say that ADH secretion is reduced during hemorrhage.
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All of the following are features of Conn's syndrome except:
- A. Alkalosis
- B. Hyperkalemia
- C. Muscle cramps
- D. Severe systemic hypertension
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.
Pseudohypoparathyroidism is not associated with:
- A. Cataract
- B. Raised level of plasma PIH
- C. Mental retardation
- D. Reduced level of plasma phosphate
Correct Answer: B
Rationale: Pseudohypoparathyroidism is a rare genetic disorder that mimics the symptoms of hypoparathyroidism, despite normal or elevated levels of parathyroid hormone (PTH). The condition is characterized by hypocalcemia, hyperphosphatemia, and normal or elevated PTH levels. However, it is not associated with a raised level of plasma PIH (Parathyroid Inhibiting Hormone). In pseudohypoparathyroidism, the body's tissues are resistant to the action of PTH, leading to impaired calcium regulation. Other common features of pseudohypoparathyroidism may include cataract formation, mental retardation, and reduced levels of plasma phosphate.
Myxoedema is characterized by all except:
- A. Butterfly rash in face
- B. Sinus bradycardia
- C. Solid oedema
- D. Madarosis
Correct Answer: A
Rationale: Myxoedema is a term used to describe severe hypothyroidism. The characteristic features of myxoedema include sinus bradycardia (choice B), solid oedema (choice C), and madarosis (choice D), which refers to loss of eyebrows and eyelashes. However, a butterfly rash is not a typical feature of myxoedema. A butterfly rash is commonly associated with conditions like systemic lupus erythematosus rather than myxoedema.
Enlargement of the bones of the hands, feet, and face due to overproduction of growth hormone is called :
- A. Acromegaly
- B. Cushing syndrome
- C. Gigantism
- D. Myxedema
Correct Answer: A
Rationale: Acromegaly is the condition characterized by the enlargement of the bones of the hands, feet, and face due to the overproduction of growth hormone in adults. This excess growth hormone typically comes from a benign tumor in the pituitary gland, leading to the gradual enlargement of these body parts. Cushing syndrome, on the other hand, is caused by prolonged exposure to high levels of cortisol and is not directly related to bone enlargement. Gigantism is the condition of excessive growth in height due to overproduction of growth hormone occurring in children before the closure of growth plates. Myxedema is a term used to describe severe hypothyroidism and is not directly associated with bone enlargement.
Aldosterone:
- A. is synthesized in the zona fasciculata.
- B. is deficient in Conn's syndrome.
- C. is independent of ACTH.
- D. is suppressed by elevated potassium.
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