In a thyroid follicle, where are the follicular cells located relative to the colloid?

• A. Periphery
• B. Center
• C. Throughout
• D. Around the capillary network

Answer: (A)

The main idea is how follicular cells are arranged around the stored colloid inside a thyroid follicle. The lumen of the follicle is filled with colloid, while a single layer of follicular cells lines the inner surface of the follicle, wrapping around the colloid at the periphery. This placement lets the cells' apical surfaces contact the colloid to process thyroglobulin and facilitate hormone synthesis, with the basal surfaces resting on a basement membrane and surrounded by capillaries in the stromal tissue to deliver hormones into the bloodstream. So, the follicular cells sit at the periphery of the colloid.