Nokea
Vanillylmandelic acid (VMA) excretion is increased in urine in:
- A. Conn's syndrome
- B. Congenital adrenal hyperplasia
- C. Testicular feminization syndrome
- D. Phaeochromocytoma
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.
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Thyroid hormones (T3 and T4):
- A. increase metabolic rate.
- B. are hydrophilic as they are made from amino acids.
- C. contain iron atoms in ferrous form.
- D. stimulate the secretion of thyroid-stimulating hormone (TSH; thyrotropin).
Correct Answer: A
Rationale: Thyroid hormones, T3 (triiodothyronine) and T4 (thyroxine), play a crucial role in regulating metabolism in the body. They are responsible for increasing the metabolic rate of cells by influencing the production of proteins and controlling how the body uses energy. This increase in metabolic rate results in processes such as increased heart rate, enhanced nutrient breakdown, and higher body temperature. Thus, option A, "increase metabolic rate," is the correct statement regarding thyroid hormones (T3 and T4).
Commonest enzymatic defect for development of congenital adrenal hyperplasia is:
- A. C-21 hydroxylase deficiency
- B. 3b dehydrogenase deficiency
- C. C-11 hydroxylase deficiency
- D. C-17 hydroxylase deficiency
Correct Answer: A
Rationale: C-21 hydroxylase deficiency is the most common enzymatic defect leading to the development of congenital adrenal hyperplasia (CAH). This enzyme is necessary for the synthesis of cortisol and aldosterone in the adrenal glands. When there is a deficiency in C-21 hydroxylase, the pathway is shifted towards the production of androgens instead of cortisol and aldosterone, leading to excess androgen production. This results in the characteristic features of CAH, such as ambiguous genitalia in females and virilization in both males and females. Other enzyme deficiencies listed in the choices can also lead to different types of CAH but are less common compared to C-21 hydroxylase deficiency.
Which of the following hormones are stored in the posterior pituitary gland?
- A. Prolactin
- B. Thyroid stimulating hormone (TSH)
- C. Growth hormone (GH)
- D. Adrenocorticotropic hormone (ACTH)
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.
Which of the following is not a feature of autonomic neuropathy in diabetes?
- A. Retrograde ejaculation
- B. Gustatory sweating
- C. Mononeuritis multiplex
- D. Hypoglycemic unresponsiveness
Correct Answer: C
Rationale: Autonomic neuropathy in diabetes can manifest with various symptoms, such as retrograde ejaculation (A), gustatory sweating (B), and hypoglycemic unresponsiveness (D). Mononeuritis multiplex (C) is not typically associated with autonomic neuropathy in diabetes. Mononeuritis multiplex is a condition characterized by damage to at least two separate nerve areas resulting in weakness, pain, and sensory loss. Autonomic neuropathy in diabetes tends to affect the autonomic nerves that control involuntary bodily functions, leading to symptoms such as gastrointestinal issues, cardiovascular abnormalities, and sexual dysfunction, but mononeuritis multiplex is not a common feature of this condition.
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.