thyroid

Question 1

normal thyroid weight

Answer 1

10-20g - slightly less in iodine deficient areas

Question 2

TSH

Answer 2

thyrotropin
from anterior pituitary
drives production, storage and release from thyroid

Question 3

TSH is controlled by

Answer 3

TRH from the hypothalamus

glucocorticoids, somatostatin, and dopamine all have an inhibitory effect

Question 4

two active thyroid hormones

Answer 4

require iodine for formation

• thyroxine T4
• 3,5,3’-triodothyronine T3

Question 5

T4 is formed in

Answer 5

thyroid gland

Question 6

T3 is formed by

Answer 6

deiodination in extra thyroidal tissues, particularly in the liver, kidney and thyroid, and muscle, brain, pituitary, skin and placenta

Question 7

thyroid hormones are bound to

Answer 7

mostly bound to serum proteins 
thyroxine binding globulin 
transthyretin 
albumin 
and lipoproteins 

represents a circulating storage pool, while unbound (free) hormone is available for uptake into the tissues and determine hormones’ biological activity

Question 8

which thyroid hormone is more active

Answer 8

T3 is more active than T4

there is variability in tissue action based on tissue distribution of receptors (2 main receptors, alpha and beta)

Question 9

is thyroid enlargement usually painful

Answer 9

no

Question 10

compression effects of goitre

Answer 10

airway, oesophagus, large vessels, nerves

either by narrowing thoracic inlet or by direct impact on adjacent structures

Question 11

important pathological conditions

Answer 11

• hyperplasia
• neoplasia
• inflammatory

Question 12

hyperplasia

Answer 12

graves disease

multi nodular goitre/nodular colloid goitre

Question 13

neoplasia

Answer 13

adenomas - follicular, hurthe cell, etc

carcinomas - papillary, follicular, anapaestic, medullary

Question 14

inflammatory

Answer 14

• Hashimoto (autoimmune)
• lymphocytic
  granulomas