Flashcards in Thyroid gland Deck (11)
What does the hypothalamus release?
TRH - thyrotropin releasing hormone
What does the anterior pituitary release?
TSH - thyroid stimulating hormone
How does the TRH travel to the pituitary?
Vua the hypophyseal portal system
What does TSH do?
Only acts on thyroid once released from the anterior pituitary
Increases trapping and iodination of tyrosine to form more T3 and T4
What is the name for T3?
What is the name for T4?
What is the negative feedback loop in thyroid hormone synthesis?
When T3 and T4 concentrations are low, production of TSH is increased
Affects hypothalamus and anterior pituitary
How are thyroid hormones synthesised?
1. TSH released from anterior pituitary stimulates thyroglobulin production in thyroid gland
2. The thyroglobulin is transported into a colloid
3. Iodide is transported into the colloid via transporter Pendrin
4. Iodination of thyroglobulin is catalysed by TPO
5. Proteolysis stimulated by TSH of iodinated thyroglobulin releases free T3 and T4
What is a colloid?
A liquid shared by many thyroidal cells within a thyroid follicle
What does TPO stand for?