Name the endocrine gland that secretes Thyroxine. Give any one function of Thyroxine.

The THYROID GLAND, situated in the neck on either side of the trachea.

Function: thyroxine regulates the BASAL METABOLIC RATE — the rate at which the body oxidises food to release energy. (Also acceptable: it controls physical, mental and sexual development in children; it regulates the metabolism of carbohydrates, fats and proteins.)

One mark for the gland and one for a function, so give both clearly.

BASAL METABOLIC RATE is the strongest single function, because every symptom of thyroid disorder follows from it: too LITTLE thyroxine — metabolism slows — weight gain, sluggishness, feeling cold too MUCH — metabolism races — weight loss, rapid heartbeat, restlessness, protruding eyeballs (exophthalmic goitre)

Thyroxine contains IODINE, which is why a dietary deficiency causes SIMPLE GOITRE — the disorder asked about in Question 2 of this same paper.