Optic nerve:
Formation: by axon of ganglionic cells of retina
Functional component: special somatic afferent
Peculiarities of optic nerve:
1. it is the prolongation of diencephalon
2. it is the white matter of brain
3. it is covered by three meninges of brain
4. its myelination is derived from oligodendrocyte so it is devoid of neurolemma sheath and no regeneration
5. pia mater project into nerve and carry blood vessels with it
Blood supply of optic nerve: superior hypophyseal artery, ophthalmic artery and posterior ciliary artery
parts of optic nerve with length :
- intra orbital part : 25 mm
- canalicular part : 5 mm
- intra cranial part : 10 mm
Total length : 4 cm
Intra orbital part is longer so eyeball can move without any tension.
No comments:
Post a Comment