part of part of has part has part has_part capable of capable of has target end location epithelial cell endocrine cell peptide hormone secreting cell epithelial cell of thyroid gland thyroid follicular cell 2010-09-08T01:50:08Z BTO:0003736 thyroid hormone secreting cell An epithelial cell that is part of the thyroid follicle epithelium, with a shape that ranges from squamous when inactive to cuboidal or columnar when active, reflecting its hormonal activity. Its apical surface is lined with microvilli projecting into the colloid-filled lumen, where it synthesizes, stores, and secretes the thyroid hormones thyroxine (T4) and triiodothyronine (T3), releasing them into the bloodstream in response to thyroid-stimulating hormone (TSH). FMA:68782 principal cell of thyroid gland thyroid gland follicular cell CALOHA:TS-1285 follicular cell of thyroid gland microvillus thyroid-stimulating hormone secretion circulatory system thyroid follicle epithelium