Optic Nerve: Difference between revisions
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== Description == | == Description == | ||
The optic nerve is a bundle of more than 1 million nerve fibers. Also known as the second cranial nerve or cranial nerve II, it is the second of several pairs of cranial nerves. It transmits sensory information for vision in the form of electrical impulses from the eye to the brain. Damage to an optic nerve can cause vision loss. The type of vision loss and how severe it is depends on where the damage occurs. It may affect one or both eyes<ref>Very well health [https://www.verywellhealth.com/optic-nerve-anatomy-4686150 Optic Nerve] Available from: https://www.verywellhealth.com/optic-nerve-anatomy-4686150<nowiki/>(accessed 4.2.2021)</ref><ref>Medline plus [https://medlineplus.gov/opticnervedisorders.html Optic Nerve] Available from:https://medlineplus.gov/opticnervedisorders.html (accessed 4.2.2021)</ref>. | The optic nerve is a bundle of more than 1 million nerve fibers. Also known as the second cranial nerve or cranial nerve II, it is the second of several pairs of cranial nerves. It transmits sensory information for vision in the form of electrical impulses from the eye to the brain. Damage to an optic nerve can cause vision loss. The type of vision loss and how severe it is depends on where the damage occurs. It may affect one or both eyes<ref>Very well health [https://www.verywellhealth.com/optic-nerve-anatomy-4686150 Optic Nerve] Available from: https://www.verywellhealth.com/optic-nerve-anatomy-4686150<nowiki/>(accessed 4.2.2021)</ref><ref>Medline plus [https://medlineplus.gov/opticnervedisorders.html Optic Nerve] Available from:https://medlineplus.gov/opticnervedisorders.html (accessed 4.2.2021)</ref>. | ||
== Course == | |||
* The optic nerve begins at the optic disk, a structure that is 1.5 mm (0.06 inch) in diameter and is located at the back of the eye. The optic disk forms from the convergence of ganglion cell output fibres (called axons) as they pass out of the eye. | |||
* When the nerve emerges from the back of the eye, it passes through the remainder of the posterior orbit (eye socket) and through the bony optic canal to emerge intracranially on the underside of the front of the brain. | |||
* At this point the optic nerve from each eye comes together and forms an X-shaped structure called the optic chiasm. Here, approximately one-half of the nerve fibres from each eye continue on the same side of the brain, and the remaining nerve fibres cross over at the chiasm to join fibres from the opposite eye on the other side of the brain. This arrangement is essential for producing binocular vision. | |||
* Posterior to the optic chiasm, the nerve fibres travel in optic tracts to various portions of the brain (predominantly the lateral geniculate nuclei and from here form the optic radiations that course toward the visual cortex located in the occipital lobes in the back of the brain. | |||
* Some nerve fibres leave the optic tract without entering the lateral geniculate nuclei and instead enter the brain stem to provide information that ultimately determines pupil size. | |||
== Function == | == Function == | ||
Revision as of 07:43, 4 February 2021
This article or area is currently under construction and may only be partially complete. Please come back soon to see the finished work! (4/02/2021)
Original Editor - Lucinda hampton
Top Contributors - Lucinda hampton, Joseph Ayotunde Aderonmu, Joao Costa and Innocent Abugu
Description[edit | edit source]
The optic nerve is a bundle of more than 1 million nerve fibers. Also known as the second cranial nerve or cranial nerve II, it is the second of several pairs of cranial nerves. It transmits sensory information for vision in the form of electrical impulses from the eye to the brain. Damage to an optic nerve can cause vision loss. The type of vision loss and how severe it is depends on where the damage occurs. It may affect one or both eyes[1][2].
Course[edit | edit source]
- The optic nerve begins at the optic disk, a structure that is 1.5 mm (0.06 inch) in diameter and is located at the back of the eye. The optic disk forms from the convergence of ganglion cell output fibres (called axons) as they pass out of the eye.
- When the nerve emerges from the back of the eye, it passes through the remainder of the posterior orbit (eye socket) and through the bony optic canal to emerge intracranially on the underside of the front of the brain.
- At this point the optic nerve from each eye comes together and forms an X-shaped structure called the optic chiasm. Here, approximately one-half of the nerve fibres from each eye continue on the same side of the brain, and the remaining nerve fibres cross over at the chiasm to join fibres from the opposite eye on the other side of the brain. This arrangement is essential for producing binocular vision.
- Posterior to the optic chiasm, the nerve fibres travel in optic tracts to various portions of the brain (predominantly the lateral geniculate nuclei and from here form the optic radiations that course toward the visual cortex located in the occipital lobes in the back of the brain.
- Some nerve fibres leave the optic tract without entering the lateral geniculate nuclei and instead enter the brain stem to provide information that ultimately determines pupil size.
Function[edit | edit source]
Motor[edit | edit source]
Sensory[edit | edit source]
Clinical relevance[edit | edit source]
Assessment[edit | edit source]
Treatment[edit | edit source]
Resources[edit | edit source]
References[edit | edit source]
- ↑ Very well health Optic Nerve Available from: https://www.verywellhealth.com/optic-nerve-anatomy-4686150(accessed 4.2.2021)
- ↑ Medline plus Optic Nerve Available from:https://medlineplus.gov/opticnervedisorders.html (accessed 4.2.2021)
