What does the thyroid gland histology reveal about colloid and follicle cells?

What does the thyroid gland histology reveal about colloid and follicle cells?

• A. Follicles lined by squamous epithelium with no colloid; parafollicular cells absent
• B. Follicles lined by pseudostratified epithelium; colloid present
• C. Follicles lined by cuboidal to columnar epithelium containing colloid; parafollicular C cells in interfollicular spaces
• D. Follicles lined by columnar epithelium with no colloid; C cells in follicles

Answer: (C)

Thyroid histology shows follicles that are the basic functional units. Each follicle is lined by a simple epithelium whose height ranges from cuboidal to low columnar; this height can increase with thyroid-stimulating hormone as the gland becomes more active. The lumen of each follicle contains colloid, a protein-rich substance that stores thyroglobulin, the precursor of thyroid hormones T3 and T4. Between follicles lie the parafollicular C cells, which secrete calcitonin and sit in the interfollicular spaces rather than inside the follicle lumen. So the classic picture is follicles with colloid in the lumen and C cells located in the spaces between follicles, not within the follicles themselves.

Thyroid histology shows follicles that are the basic functional units. Each follicle is lined by a simple epithelium whose height ranges from cuboidal to low columnar; this height can increase with thyroid-stimulating hormone as the gland becomes more active. The lumen of each follicle contains colloid, a protein-rich substance that stores thyroglobulin, the precursor of thyroid hormones T3 and T4. Between follicles lie the parafollicular C cells, which secrete calcitonin and sit in the interfollicular spaces rather than inside the follicle lumen. So the classic picture is follicles with colloid in the lumen and C cells located in the spaces between follicles, not within the follicles themselves.