A protein-rich fluid found within the follicles of the thyroid gland, where thyroid hormone synthesis occurs.
2
New cards
Follicles
Spherical structures in the thyroid gland that contain colloid and are lined by follicular cells responsible for thyroid hormone production.
3
New cards
Iodide trapping
The active transport of iodide ions from the bloodstream into thyroid follicular cells.
4
New cards
Pendrin
A protein that transports iodide from follicular cells into the colloid for hormone synthesis.
5
New cards
Thyroglobulin
A glycoprotein produced by follicular cells that serves as a precursor for thyroid hormone synthesis.
6
New cards
Thyroid hormone
A collective term for the hormones T3 (triiodothyronine) and T4 (thyroxine), which regulate metabolism.
7
New cards
Thyroxine (T4)
The predominant thyroid hormone in circulation; contains four iodine atoms.
8
New cards
Triiodothyronine (T3)
The more biologically active thyroid hormone; contains three iodine atoms.
9
New cards
Where is the thyroid gland located and what is its composition?
The thyroid gland is located in the anterior neck, just below the larynx, composed of numerous follicles filled with colloid and lined by follicular cells.
10
New cards
What is the difference between the structure of thyroxine and triiodothyronine in relation to the number of iodines?
T4 has four iodine atoms, whereas T3 has three; T4 is more abundant in blood plasma, but T3 is more biologically active.