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: D

Rationale: The correct answer is D: second messengers. Protein hormones typically bind to cell surface receptors, activating second messenger systems to relay the signal inside the cell. This mechanism allows for rapid and amplified cellular responses. Choices A and B (cytoplasmic and nuclear receptors) are more commonly associated with steroid hormones, not protein hormones. Choice C (cyclic ribosomal adenosine phosphate) is not a known mechanism of hormone action. Thus, the correct answer is D, as second messengers are the primary mediators of protein hormone actions.

Correct Answer: A

Rationale: The correct answer is A because Klinefelter's syndrome is characterized by small, soft testes due to the presence of an extra X chromosome (47, XXY). This leads to hypogonadism and inadequate testosterone production, resulting in underdeveloped testes. Choice B (46, XO) is incorrect as it refers to Turner syndrome. Choice C (upper segment> lower segment) is unrelated to Klinefelter's syndrome. Choice D (Gynaecomastia) is a symptom of Klinefelter's syndrome but not the defining characteristic.

Correct Answer: C

Rationale: Step-by-step rationale for why choice C is correct: 1. Growth hormone stimulates increased production of insulin-like growth factor 1 (IGF-1). 2. In acromegaly, there is excessive production of growth hormone. 3. Excess growth hormone leads to elevated levels of IGF-1. 4. IGF-1 is primarily produced in the liver in response to growth hormone stimulation. 5. Therefore, increased levels of growth hormone in acromegaly stimulate increased production of IGF-1 from the liver. Summary: - Choice A is incorrect because vasopressin is not produced from the adrenal glands in response to growth hormone. - Choice B is incorrect because vasopressin is not produced from the liver in response to growth hormone. - Choice D is incorrect because IGF-1 is mainly produced in the liver, not from the adrenal glands, in response to growth hormone.

Correct Answer: C

Rationale: The correct answer is C: Ischaemic heart disease. Metabolic syndrome X consists of a cluster of conditions, including hyperlipidemia, obesity, hypertension, and insulin resistance. Ischaemic heart disease, while commonly associated with metabolic syndrome X due to the increased risk factors, is not a direct component of the syndrome itself. Therefore, it is not considered a part of metabolic syndrome X. Hyperlipidemia (A), obesity (B), and hypertension (D) are all key components of metabolic syndrome X due to their association with insulin resistance and increased risk of cardiovascular disease.