Optic Nerve: Anatomy, Location, And Function

Optic Nerve: Anatomy, Location, And Function

Describe the optic nerve in brief and mention its unique features.

Answer. The optic nerve is the nerve of sight, i.e. vision.

Functional Components Of Optic Nerve Special somatic afferent fibres for the special sense of sight.

Optic Nerve Origin And Course The optic nerve extends from the eyeball to the optic chiasma, which lies above the pituitary fossa containing the pituitary gland. Its fibres arise from the retina and leave the eyeball at the optic disc.

The fibres arising from the nasal half of the retina decussate in the optic chiasma with that of the opposite side and then course along the optic tract of the opposite side, whereas those arising from the temporal half of the retina do not decussate in the optic chiasma and thus run in the optic tract of the same side. The fibres of the optic tract relay in the lateral geniculate body.

Unique Features Of Optic Nerve

• The optic nerve is not a true peripheral nerve, rather it is a tract of the forebrain.
• The optic nerve is surrounded by meninges, i.e. dura mater, arachnoid mater and pia mater, and thus by a subarachnoid space containing CSF.
• Optic nerve fibres are myelinated by oligodendrocytes and not by Schwann cells. (cf. The fibres of peripheral nerves are myelinated by the Schwann cells.)
• Optic nervecannot regenerate if damaged.

Applied Anatomy Of Optic Nerve – The damage of the optic nerve leads to complete blindness on the side of the lesion.