Neurogenic placodes

In humans

• dorsolateral placodes includes:
• * The trigeminal placode, which consists of ophthalmic and maxillomandibular parts, and gives rise to the cells of the trigeminal ganglion
• * The otic placode forms the otic pit and the otic vesicle, giving rise eventually to organs of hearing and equilibrium.
• The epibranchial or epipharyngeal placodes generate the distal portion of the ganglia of cranial nerves VII, IX and X:
• * The geniculate placode, associated with the first pharyngeal groove, generates the geniculate ganglion and distal parts of cranial nerve VII
• * The petrosal placode, associated with the second pharyngeal groove, generates the inferior ganglion of glossopharyngeal nerve and distal parts of cranial nerve IX
• * The nodosal placode, associated with the third branchial cleft, generates the nodose ganglion and distal parts of cranial nerve X
• The olfactory placode gives rise to the olfactory epithelium of the nose.
• The cranial placodes that do not give rise to neurons are:
• * The lens placode under the direction of the optic vesicle gives rise to the lens of the eye.
• * The adenohypophyseal placode, which forms the anterior lobe of the pituitary gland.

  Other animals

• The profundal placode, corresponding to the ophthalmic lobe of the trigeminal complex. In Xenopus this remains partly unfused.
• In aquatic vertebrates, the lateral line placodes, which give rise to the lateral line system.
• The hypobranchial placodes, a neurogenic placode found in some amphibians of unknown function

  Other ectodermal placodes