T₃ and T₄ are stored in the lumen of thyroid follicles as part of the ________ molecule.

A) thyrotropin
B) thyroid-stimulating hormone
C) thyroxine-binding protein
D) thyroglobulin
E) calcitonin

Thyroglobulin

A glycoprotein produced by the thyroid gland, serving as a precursor for thyroid hormones and important for thyroid function.

Thyroid Follicles

Microscopic, spherical sacs found in the thyroid gland, responsible for the production and storage of thyroid hormones.

Thyroxine-binding Protein

A plasma protein that transports thyroxine, a hormone responsible for regulating metabolism, throughout the bloodstream.