Endocrinology Practice Questions

Correct Answer: A

Rationale: The correct answer is A: Cirrhosis. In cirrhosis, there is a decrease in the binding proteins for T4, leading to decreased total T4 levels in the plasma. Pregnancy, euthyroid sick syndrome, and familial excess thyroid binding globulin are all conditions associated with increased total T4 levels due to various physiological changes. In pregnancy, there is an increase in thyroid hormone production to support fetal development. Euthyroid sick syndrome is a condition where there is a decrease in binding proteins, leading to an increase in free T4 levels but normal total T4 levels. Familial excess thyroid binding globulin causes an increase in total T4 levels due to excessive binding proteins.

Correct Answer: C

Rationale: Sertoli cells are responsible for producing and secreting Androgen binding globulin (ABG). They play a crucial role in supporting spermatogenesis by providing structural and nutritional support to developing sperm cells. ABG helps in the transport of testosterone and other androgens within the seminiferous tubules, aiding in the regulation of spermatogenesis. Testosterone is primarily produced by Leydig cells in the testes, not by Sertoli cells, making option A incorrect. Option B, Oestrogen, is mainly synthesized in the ovaries, while Sertoli cells do not produce GnRH (option D), which is secreted by the hypothalamus. Therefore, the correct answer is C, as Sertoli cells are primarily responsible for producing and secreting Androgen binding globulin.

Correct Answer: B

Rationale: The correct answer is B: ductless. Endocrine glands release hormones directly into the bloodstream without the use of ducts. This allows hormones to reach target organs throughout the body. Choice A (vascular) is incorrect because it refers to the presence of blood vessels, which is common in all glands, not just endocrine glands. Choice C (square) is irrelevant as the shape of glands does not determine their function. Choice D (autonomous) is incorrect as it does not accurately describe endocrine glands; while they function independently, the term "autonomous" does not specifically apply to them.

Correct Answer: B

Rationale: The correct answer is B: Cretinism. Cretinism is the most common cause of preventable mental deficiency worldwide due to severe iodine deficiency during pregnancy. Iodine is crucial for thyroid hormone production, which is essential for fetal brain development. Beriberi disease (A) is caused by thiamine deficiency and affects the nervous system, not mental deficiency. Folate deficiency (C) can cause neural tube defects but not mental deficiency. Vitamin A deficiency (D) can lead to blindness and immune system issues, but not the most common cause of preventable mental deficiency.

Correct Answer: C

Rationale: Increased parathyroid hormone (PTH) concentration is associated with tetany because PTH helps regulate calcium levels in the blood. When calcium levels are low, PTH is released to stimulate the release of calcium from bones and increase calcium absorption from the intestines. Tetany is characterized by muscle cramps and spasms due to low calcium levels, which can occur when PTH levels are elevated. A: Vitamin D toxicity is associated with high levels of calcium in the blood, not low calcium levels as seen in tetany. B: Rickets is a condition caused by vitamin D deficiency, leading to impaired bone growth and development, not directly related to elevated PTH levels. D: Reduced excretion of phosphate is not directly linked to elevated PTH levels, as PTH primarily regulates calcium levels.