Definition for Ectoderm
From Biology Forums Dictionary
The outermost layer of cells formed during gastrulation that covers the surface of the embryo and differentiates into the epidermis and nervous system.
Derivatives originate from:
(a) Somatic ectoderm: e.g., epidermis; hair and feathers; skin glands; olfactory organs; eye lens; inner ear; anterior pituitary gland.
(b) Neural tube: brain, spinal cord, retina, optic nerve, posterior pituitary, cranial nerves, spinal motor nerves.
(c) Neural crest: e.g., chromatophores; Schwann cells and myelin; adrenal medulla; cells of cranial, spinal, and autonomic ganglia; branchial skeleton; parts of the cranial skeleton.