Nokea
Which of the following is the most potent stimulus for hypothalamic production of arginine vasopressin?
- A. Hypertonicity
- B. Hyperkalemia
- C. Hypokalemia
- D. Hypotonicity
Correct Answer: A
Rationale: Hypertonicity (increased osmolarity or high concentration of solutes in the blood) is the most potent stimulus for the hypothalamic production of arginine vasopressin (also known as antidiuretic hormone or ADH). When the body senses increased plasma osmolality, the osmoreceptors in the hypothalamus stimulate the release of vasopressin from the posterior pituitary gland. Vasopressin acts on the kidneys to increase water reabsorption and decrease urine output, helping to restore normal osmolarity. This mechanism helps to conserve water and maintain body fluid balance in response to dehydration or increased solute concentration in the blood.
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Increased gonadal production of oestrogen is seen in:
- A. Third trimester of pregnancy
- B. Congenital adrenal hyperplasia
- C. Polycystic ovarian disease
- D. Testicular feminization syndrome
Correct Answer: C
Rationale: Polycystic ovarian disease, also known as polycystic ovary syndrome (PCOS), is a common endocrine disorder characterized by increased levels of androgens (male hormones) and disrupted estrogen production in the ovaries. The hormonal imbalance seen in PCOS leads to increased gonadal production of estrogen. This condition is often associated with symptoms such as irregular menstrual cycles, infertility, acne, and excess facial or body hair growth. In contrast, the other options do not typically involve increased gonadal production of estrogen as seen in PCOS.
Which of the following is a complication of diabetes mellitus?
- A. Gastroparesis
- B. Exophthalmos
- C. Hirsutism
- D. Moon facies
Correct Answer: A
Rationale: Gastroparesis is a complication of diabetes mellitus. It is a condition that affects the normal spontaneous movement of the muscles in the stomach, causing delayed emptying of food from the stomach into the small intestine. This can lead to symptoms such as nausea, vomiting, bloating, and poor appetite. Diabetes can damage the nerves that control the stomach muscles, resulting in gastroparesis. Managing blood sugar levels and following a proper diet can help in controlling the symptoms of gastroparesis in individuals with diabetes. Exophthalmos, hirsutism, and moon facies are not typically associated with complications of diabetes mellitus.
Acromegaly is associated with all of the following except:
- A. Acanthosis nigricans
- B. Fibromata mollusca
- C. Micrognathia
- D. Cardiomegaly
Correct Answer: C
Rationale: Acromegaly is a disorder caused by excessive growth hormone production after the closure of the epiphyses (growth plates) in bones, leading to abnormal growth of tissues and organs. The following options are associated with acromegaly:
Which of the following are not causes of neurogenic diabetes insipidus?
- A. Sheehan's syndrome
- B. Mutations in the vasopressin (ADH) receptor gene
- C. Meningitis
- D. Mutations in the vasopressin gene
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.
Which cranial nerve is not involved in acromegaly?
- A. VIII
- B. III, IV, VI
- C. V
- D. Il
Correct Answer: A
Rationale: Acromegaly is a disorder caused by the overproduction of growth hormone in adulthood, usually due to a pituitary tumor. The cranial nerves that may be affected in acromegaly are Cranial Nerves III, IV, VI (oculomotor, trochlear, abducens) due to compression of the optic chiasm by the expanding tumor. Cranial Nerve V (trigeminal nerve) may also be affected given its close proximity to the pituitary gland. However, Cranial Nerve VIII (vestibulocochlear nerve) is not typically involved in acromegaly.