thyroid

Question 1

name the 2 thyroid hormones and their basic functions and differences.

Answer 1

thyroxine (T4)
- lots produced
- prohormone that converts into T3
- role - healps to maintain steads T3 levels

triiodothyronine (T3)
- more potent
- active form of thyroid hormone

Question 2

describe the control and negative feedback of thyroif hormones.

Answer 2

hypothalamus - TRH
anterior pituitary - TSH
thyroid gland - T4 - T3

T3 - target tissues

the more T3 - inhibits anterior pituitary from releasing TSH

Question 3

name the major regulatory step in thyroid hormone control

Answer 3

T3 inhibiting TSH release from the anterior pituitary

Question 4

name some basic roles of T3.

Answer 4

Accelerates food metabolism
Increases protein synthesis
Stimulation of carbohydrate metabolism
Enhances fat metabolism
Increase in ventilation rate
Increase in cardiac output and heart rate
Brain development during foetal life and postnatal development
Growth rate accelerated

Question 5

name of iodinated protein

Answer 5

thyroglobulin

Question 6

effect of iodine on thyroid

Answer 6

Jod-Basedow phenomenon
Increased iodine exposure causing hyperthyroidism for example in iodine deficient patients exposed to iodine

Wolff-Chaikoff effect
Anti-thyroid effect of excess iodine. Inhibits thyroperoxidase function by reducing iodide oxidation inhibiting release of thyroid hormones

Question 7

why is there a wide range of effects from TSH?

Answer 7

TSH receptors ubiquitous