Endocrine Glands & Their Hormones — NEET Biology

Correct answer: B — S1, S2 and S5 are correct

This question assesses the comprehensive understanding of various hormone-producing structures within the human body, as described in the NCERT text. S1. Pituitary, thyroid, adrenal, pancreas, and gonads are examples of organised endocrine glands. This statement is CORRECT. NCERT states: "Pituitary, pineal, thyroid, adrenal, pancreas, parathyroid, thymus and gonads... are the organised endocrine bodies in our body." S2. The gastrointestinal tract contains diffuse hormone-producing cells, distinct from classical endocrine glands. This statement is CORRECT. NCERT mentions: "Endocrine cells present in different parts of the gastro-intestinal tract secrete four major peptide hormones" and earlier refers to "diffused hormone-producing tissues/cells". S3. Organs like the heart and kidney are not typically considered part of the endocrine system despite producing hormones. This statement is NOT CORRECT. NCERT explicitly states: "In addition to these [organised glands], some other organs, e.g., gastrointestinal tract, liver, kidney, heart also produce hormones." This implies they are part of the broader endocrine system. S4. A composite gland like the pancreas functions solely as an endocrine gland, secreting hormones. This statement is NOT CORRECT. NCERT states: "Pancreas is a composite gland... which acts as both exocrine and endocrine gland." S5. The modern definition of hormones expands the scope beyond chemicals produced only by organised endocrine glands. This statement is CORRECT. NCERT mentions: "The new definition covers a number of new molecules in addition to the hormones secreted by the organised endocrine glands." Therefore, statements S1, S2, and S5 are correct. Option A is incorrect because S3 is false. Option C is incorrect because S3 and S4 are false. Option D is incorrect because S4 is false. Option B correctly identifies S1, S2, and S5 as the correct statements. Recap: The endocrine system includes organised glands, diffuse tissues, and other hormone-producing organs, and the modern definition of hormones is broad.