a) Optic nerve
Second cranial nerve.
Extends from the eye to the optic chiasma.
May be considered to be an extension of the brain
Has got three parts: Orbital, canalicular and intra cranial
Contains second order neurons
Sorrounded by meninges and tendons of extra ocular muscles
Traversed by central artery and central vein of retina
Note the optic nerve  , optic chiasma  and optic tract