Lecture 17 - Thyroid

Question 1

Normal functions of the thyroid?

Answer 1

normal growth & development, metabolic and oxygen, lipid and carbohydrate metabolism (body weight)

Question 2

Embryology of thyroid?

Answer 2

endoderm origin, in thyroglossal duct, functional 12 weeks, independent 20 weeks,

Question 3

Surroundings of thyroid?

Answer 3

recurrent pharyngeal nerves (posterior), oesophagus (to the left), superior and inferior thyroid artery, deep to sterno-hyoid muscle

Question 4

Iodine?

Answer 4

150 microg/day, from salt, fish and bread, or supplements (pregnancy), deficiency leads to thyroid enlargement (Goitre)

Question 5

Locations of Sodium-Iodide symporter?

Answer 5

thyroid, breast, gastric mucosa, salivary glands, cancer thyroid cells

Question 6

Rare thyrotoxicity from overdose of thyroid supplements?

Answer 6

factitious thyrotoxicosis

Question 7

Parafollicular cells?

Answer 7

calcitonin, linked to medullary thyroid cancer

Question 8

Thyroid pyroxidase?

Answer 8

measured in hyper and hypothyroid, enzyme involved in T3 and 4 production

Question 9

Hyperthyroid/thyrotoxicosis drug?

Answer 9

carbimazole

Question 10

T4 and 3 bind to?

Answer 10

tissue receptors with alpha (LH, FSH, TSH and HCG) and beta subunits

Question 11

HCG thyroid?

Answer 11

in pregnancy, partial stimulation of TSH receptros which leads to a normal decline in TSH, and a rise in T3 and 4

Question 12

Iodide and TSH?

Answer 12

TSH stimulates increases iodide in follicular lumen, increasing endocytosis to form T4, which converts to T3 in periphery; also increases blood flow, Tg, TPO and pyroxide

Question 13

Regulation of thyroid hormone?

Answer 13

TRH, TSH and T3 negatively feedback in pituitary

Question 14

Thyrotoxicosis/hyperthyroid - symptoms?

Answer 14

nervousness, weight loss, heat sensitive, tachycardia, weakness

Question 15

Thyrotoxicosis/hyperthyroid - signs?

Answer 15

Goitre, skin changes, tremor, eye inflammation (glycans infiltrating fat)

Question 16

Graves Disease?

Answer 16

autoimmune production of antibody that stimulates TSH receptor

Question 17

Goitre?

Answer 17

Hyper-functioning regions of thyroid gland, not suppressed by circulating thyroid hormone

Question 18

Hypothyroidism symptoms?

Answer 18

weight gain, cold, hair loss, constipation, oedema

Question 19

Hypothyroidism diagnosis?

Answer 19

low t4 and t3, high tsh; positive for TOP suggests Hashimoto’s disease