Science — CBSE Class 10 board question

(i)

| Hormone | Disorder | Gland |
|---|---|---|
| (I) Over-secretion of Growth Hormone | Gigantism (in children) / Acromegaly (in adults) | Pituitary gland |
| (II) Deficiency of Oestrogen | Osteoporosis / irregular menstrual cycle | Ovary |
| (III) Less secretion of Thyroxine | Goitre / Hypothyroidism | Thyroid gland |

(ii) Regulation of Hormone Release — Feedback Mechanism:

The timing and amount of hormone released is regulated by a feedback mechanism.

Example: When blood sugar rises, the pancreas secretes more insulin, which lowers blood glucose. When blood sugar returns to normal, further secretion of insulin is stopped. This self-regulating loop — where the effect of the hormone feeds back to control its own secretion — is called negative feedback.

Similarly, if thyroid hormone levels fall, the pituitary releases TSH to stimulate the thyroid; once levels are normal, TSH secretion decreases.

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• Part (i) is straightforward recall — examiners expect all three disorders AND all three glands named correctly. Missing either costs marks.
• Part (ii) must name the mechanism (feedback/negative feedback) and give a clear example showing stimulus → hormone release → effect → regulation. The insulin/blood sugar example is the most commonly expected one in CBSE. Two marks typically go to the concept and one to the example.
• Do not write long paragraphs — a table for (i) and 4–5 lines for (ii) is sufficient.