Control of thyroxine level

Question 1

What method of control is used to control thyroxine levels?

Answer 1

Negative feedback

Question 2

What is the negative feedback method of control?

Answer 2

The correct level of one item has a negative effect on a pervious step in the cycle

Question 3

What happens if there are normal concentrations of thyroxine in the body?

Answer 3

The pituitary gland is inhibited from releasing thyroid-stimulating hormone (TSH) which means no more thyroxine is made

Question 4

What happens if there is a low concentration of thyroxine in the body?

Answer 4

The pituitary glans produces TSH which causes more thyroxine to be made by the thyroid gland until thyroxine concentration has returned to normal

Question 5

What is essential for the production of thyroxine?

Answer 5

Iodine

Question 6

What disease is caused by an underproduction of thyroxine?

Answer 6

Goitre

Question 7

What usually causes goitre?

Answer 7

A lack of iodine in the diet

Question 8

What does a low concentration of thyroxine in the blood cause?

Answer 8

It causes the pituitary gland to produce TSH which is then carried by the blood to the thyroid

Question 9

What does TSH usually combine with to produce thyroxine?

Answer 9

Iodine

Question 10

What does TSH combine with iodine to produce?

Answer 10

Thyroxine

Question 11

What happens if there is a shortage of iodine in the body?

Answer 11

TSH is stored in the thyroid which causes it to swell (goitre) which can be treated by increasing iodine in the diet