The diagram given below represents the location and structure of an endocrine gland. Study the same and answer the questions that follow: The diagram given below represents the location and structure of an endocrine gland. Study the same and answer the questions that follow:
Name the mineral element required for the synthesis of the above mentioned hormone.
Topic: Iodine
Answer
IODINE.
Thyroxine is an IODINE-CONTAINING hormone, so the thyroid cannot make it without a dietary supply of iodine.
WHAT HAPPENS WITHOUT IT — and the mechanism is worth knowing because it seems paradoxical: lacking iodine, the gland cannot make thyroxine; the low thyroxine level removes the feedback that restrains the pituitary; the pituitary pours out more TSH; and TSH stimulates the thyroid tissue to GROW. So the gland ENLARGES while producing LESS — which is SIMPLE GOITRE.
This is why table salt is IODISED, a cheap public-health measure that has largely eliminated the disease in India — and why goitre was historically common in hilly regions, where rain and snow melt leach iodine from the soil.