Karyotype 47, XYY is:
- A. True hermaphroditism
- B. Supermale
- C. Klinefelter's syndrome
- D. Gonadal dysgenesis
Correct Answer: B
Rationale: Karyotype 47, XYY refers to the presence of an extra Y chromosome in males. This condition is known as XYY syndrome, also called Jacob's syndrome. Individuals with XYY syndrome are typically phenotypically male but may have some associated physical and behavioral characteristics. These individuals are often referred to as "supermales" due to the presence of the extra Y chromosome. This is different from true hermaphroditism, Klinefelter's syndrome, and gonadal dysgenesis, which have distinct chromosomal patterns and manifestations.
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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.
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.
Which of the following statements best describes Hashimoto's thyroiditis?
- A. Inflammation of the thyroid gland as the result of a virus. The disease is often preceded by an upper respiratory tract infection.
- B. A destructive autoimmune disease caused by auto-reactive antibodies against thyroglobulin.
- C. Iodine deficiency
- D. thyroid gland
Correct Answer: B
Rationale: Hashimoto's thyroiditis is an autoimmune disease where the immune system mistakenly attacks the thyroid gland. The antibodies produced by the immune system target the thyroglobulin in the thyroid gland, leading to its destruction over time. This results in decreased thyroid hormone production, leading to hypothyroidism. Therefore, choice B, "A destructive autoimmune disease caused by auto-reactive antibodies against thyroglobulin," best describes Hashimoto's thyroiditis.
All of the following are potential causes of elevated LDL , except:
- A. Cirrhosis
- B. Hypothyroidism
- C. Nephrotic syndrome
- D. Thiazide diuretics
Correct Answer: A
Rationale: Cirrhosis is not a potential cause of elevated LDL cholesterol levels. The liver plays a significant role in cholesterol metabolism, and liver disease like cirrhosis can actually lead to decreased levels of LDL cholesterol. Elevated LDL cholesterol levels can be caused by conditions such as hypothyroidism, nephrotic syndrome, or the use of certain medications like thiazide diuretics.
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.