Prolonged ingestion of iodine can produce goiter, and is known as:
- A. Jod-Basedow effect
- B. Sick euthyroid syndrome
- C. Wolf-Chaikoff effect
- D. Thyrotoxicosis factitia
Correct Answer: C
Rationale: The prolonged ingestion of iodine causing goiter is known as the Wolf-Chaikoff effect. This phenomenon occurs when high levels of iodine cause a temporary inhibition of thyroid hormone synthesis, resulting in a decrease in thyroid hormone production. In some individuals, this can lead to the development of a goiter due to the lack of thyroid hormone feedback regulation. It is important to note that the Wolf-Chaikoff effect typically resolves on its own as the thyroid gland adapts to the increased iodine levels over time.
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Tall stature is not characteristic of:
- A. Klinefelter's syndrome
- B. Homocystinuria
- C. Marfan's syndrome
- D. Turner's syndrome
Correct Answer: D
Rationale: Turner's syndrome is a genetic condition that affects females and is characterized by short stature and other physical abnormalities due to the absence of part or all of one of the X chromosomes. Therefore, tall stature is not characteristic of Turner's syndrome.
Oxytocin:
- A. is bound to neurophysin in plasma.
- B. inhibits production of milk.
- C. inhibits myometrial contraction.
- D. inhibits sperm swimming on the gonad.
Correct Answer: A
Rationale: Oxytocin is a hormone produced by the hypothalamus and released by the pituitary gland. In the bloodstream, oxytocin is mostly bound to a carrier protein called neurophysin. This binding helps to protect oxytocin from being degraded too quickly in the bloodstream, thus allowing it to exert its effects on target tissues such as the uterus and mammary glands. Oxytocin plays important roles in stimulating uterine contractions during labor, facilitating milk letdown during breastfeeding, and promoting social bonding and emotional connections.
Increased serum aldosterone level is not associated with:
- A. Hypertension
- B. Hypernatraernia
- C. Hypokalaemia
- D. Metabolic acidosis
Correct Answer: D
Rationale: Increased serum aldosterone level is typically associated with conditions such as Conn's syndrome or primary hyperaldosteronism. These conditions lead to an excess of aldosterone, which results in increased sodium resorption and potassium excretion by the kidneys. This imbalance can lead to hypertension (Choice A), hypernatraernia (elevated sodium level) (Choice B), and hypokalaemia (low potassium level) (Choice C). However, metabolic acidosis (Choice D) is not directly associated with increased aldosterone levels. Instead, metabolic acidosis may be seen in conditions like renal tubular acidosis or diabetic ketoacidosis.
Regarding syndrome of inappropriate antidiuretic hormone (SIADH), which is true?
- A. Hyponatremia is dilutional
- B. Urine is relatively hypertonic to plasma
- C. ADH-mediated water reabsorption does not occur
- D. Renal function is jeopardized
Correct Answer: A
Rationale: In the syndrome of inappropriate antidiuretic hormone (SIADH), there is excessive secretion of antidiuretic hormone (ADH) leading to increased water reabsorption in the kidney tubules. This results in dilutional hyponatremia because the amount of water reabsorbed is greater than the electrolytes, such as sodium, leading to a relative decrease in their concentration in the blood. As a result, hyponatremia occurs in SIADH, contributing to symptoms such as nausea, confusion, and seizures due to the imbalance in electrolytes.
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.