Parafolliculars gland of thyroid developed from
D. i.e. (Neural crest) (320 - I.B.S 8,h)* Derivatives of Endoderm = Glands(a) Endocrine: Thyroid, Parathyroid, Thymus , Islets of langerhans(b) Exocrine: Liver, Pancreas, Glands in wall of GIT, greater part of prostate (except inner glandular zone) and its female homologous* The superior parathyroid glands arise from caudal pharyngeal complex, the complex probably also gives origin to the parafollicular cells of the thyroid. Which may represent the ultimo branchial body of lower animals.*** "C- cells" parafollicuiars, constitute and endocrine system which are derived from neural crest and are found in thyroid, parathyroid and in thymus (544- Rana-shinde 7th)NEURAL -CREST - DERIVATIVES (273-74- IBS 8th)1. The neurons of the spinal posterior nerve root ganglia2. The neurons of the sensory ganglia of the 5, 7, 8, 9 and 10th cranial nerves.3. The Schwann cells that form the neurolemmal sheaths of all peripheral nerves4. The neurons of the sympathetic ganglia5. The specific cells of the adrenal medulla6. Chromaffin tissue7. The pigment cells (melanoblasts**) of the skin8. The pia mater and arachnoidmater are also, probably, derived from the neural crest9. The mesenchyme of the dental papillae (odontoblast**) Some diseases and syndromes are associated with disturbances of the Neural crestHirschsprung's disease (aganglionic megacolon**). Aorticopulmonary septal defects of heart. Cleft lip, cleft palate, frontonasal dysplasia, neurofibromatosis, tumours of adrenal medulla, albinism
Ectoderm
Mesoderm
Endoderm
Neural crest
Embryology