NME 2.30 Flashcards
1
Q
describe structure of thyroid gland?
A
- bow tie shape
- anterior neck front of trachea
- consist of right and left lobes
2
Q
what is the function of thyroid gland?
A
- produce thyroid hormones
- controls how quickly the body uses energy, makes proteins
- controls how sensitive the body is to other hormones
3
Q
when does fetal thyroid start producing thyroid hormones?
A
12 weeks of gestation
4
Q
what is the development of thyroid dependent on?
A
- TTF1/2
- PAX8 genes
5
Q
what does T3 and T4 do?
A
- regulate metabolism
- affect the rate of function of other systems of the body
6
Q
what is T3 and T4 derived from?
A
- thyroglobulin
7
Q
what cells synthesised thyroid hormones?
A
- follicular cells
8
Q
how are thyroid hormones released
A
- follicular cells release thyroglobulin
- iodine will attach
- iodinated thyroglobulin will be taken up by follicular cells and hydrolysed in lysosomes
- secreted into circulation
9
Q
what happens when deiodinate outer ring?
A
become active hormone
10
Q
what happens when deiodinat the inner ring?
A
become biologically inactive form
11
Q
what catalysed the formation of active T3
A
- type 1 deiodinase
12
Q
what is the hypothalamic-pituitary thyroid axis?
A
- hypothalamus release thyrotropin releasing hormone
- stimulate pituitary to release thyroid stimulating hormone
- then thyroid release T3 and T4
13
Q
what helps to regulat and contorl thyroid hormone synthesis?
A
- hypothalamic-pituitary-thyroid axis
14
Q
what inhibits secretion of TSH?
A
- T3
- T4
- dopamine
- somatostatin
