thyroid hormone

Question 1

What are the main structural components of the thyroid gland?

Answer 1

follicles lined with follicular cells and filled with colloid

Question 2

What are the primary hormones produced by the thyroid gland?

Answer 2

T3 T4

Question 3

What additional hormone does the thyroid gland produce and its function?

Answer 3

calcitonin, which helps regulate calcium levels

Question 4

10 steps of thyroid hormone synthesis

Answer 4

1. TRH release from hypothalamus
2. Ani Pit release TSH
3. TSH simulates follicular cells to synthesise thyroglobulin
4. iodide trapping
5. oxidation of iodide
   6.iodination of tyrosine amino acids
   7.couple DIT and MIT
   8.endocytosis of thyroglobulin with T3 and T4
6. lysosomal enzymes cleave T3 and T4 out of thyroglobulin
7. exocytosis of T3 and T4 into blood plasma

Question 5

T4 converted to T3 by ?

Answer 5

deiodoniase enzyme

Question 6

what is the iodine trap

Answer 6

uptake of iodide through iodide-sodium symporter across basolateral membrane

Question 7

What is the role of T3 in transcriptional regulation?

Answer 7

T3 binds to thyroid receptor to regulate transcription

Question 8

What is the significance of dimerization in thyroid hormone action?

Answer 8

TR often forms a heterodimer with retinoid X receptor (RXR) to enhance binding to thyroid hormone response elements (TREs).

Question 9

What are TREs and their function?

Answer 9

specific DNA sequences in target gene promoters that TR binds to regulate transcription.

Question 10

name a corepressor

Answer 10

HDAC

Question 11

name a coactivator

Answer 11

HAT

Question 12

physiological effects of thyroid hormones

Answer 12

accelerated metabolism
development and growth

Question 13

thyroid hormones effects on autonomic nervous system

Answer 13

increases b-adrenergic receptors and intracellular second messengers

Question 14

what is hyperthyroidism

Answer 14

excessive production of thyroid hormone

Question 15

what autoimmune disease can cause hyperthyroidism

Answer 15

graves disease

Question 16

What are typical symptoms of hyperthyroidism?

Answer 16

Increased heart rate, weight loss, anxiety, heat intolerance, sweating, and tremors

Question 17

what is hypothyroidism

Answer 17

insufficient production of thyroid hormone

Question 18

what can cause hypothyroidism

Answer 18

Hashimoto disease
dietary iodine deficiency
defective pituitary function

Question 19

What are typical symptoms of hypothyroidism?

Answer 19

Fatigue, weight gain, cold intolerance, dry skin, hair loss, and depression

Question 20

what is goitre

Answer 20

enlarged thyroid gland

Question 21

effect of thioureylenes

Answer 21

inhibit thyroid hormone synthesis

Question 22

what is the major method for treating hyperthyroidism

Answer 22

radioiodine

Question 23

What is the Wolff-Chaikoff effect?

Answer 23

A temporary reduction in thyroid hormone production

Question 24

name a b-adrenoceptor antagonist

Answer 24

propananolol

Question 25

what is propranolol used for

Answer 25

block noradrenaline overstimulation of cardiac B1-adrenoceptors

Question 26

treatment of hypothyroidism

Answer 26

synthetic hormones

Question 27

What is the importance of MCT8 in the brain?

Answer 27

transports T3 into neuron

Question 28

which chromosome is MCT8 located on

Answer 28

X

Question 29

allan-herdon-dudley syndrome is a mutation in

Answer 29

MCT8