A histology slide of thyroid gland shows parafollicular (C) cells secreting calcitonin. These cells are derived from which embryological structure?
- A Thyroglossal duct epithelium
- B Ultimobranchial body of the fourth pharyngeal pouch ✓
- C Third pharyngeal pouch endoderm
- D Neural crest ectoderm of the second arch
Correct answer: B. Ultimobranchial body of the fourth pharyngeal pouch
Explanation
The ultimobranchial body arises from the fourth (with contributions from the fifth or caudal) pharyngeal pouch and migrates into the thyroid, where its cells differentiate into parafollicular C cells. The follicular cells of the thyroid arise from the median thyroglossal duct endoderm, not the ultimobranchial body. Third pouch tissue forms the thymus and inferior parathyroids, not C cells.
Reference: Langman's Medical Embryology, 14th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.