Optic Nerve Flashcards

Examine the optic nerve's retinal origins, anatomical course, visual pathway connections, blood supply, and clinical significance.

Card 1 of 30Question

What is the numerical designation of the optic nerve?

Cranial nerve II (CN II).

In This Section

1. What is the numerical designation of the optic nerve?

Cranial nerve II (CN II).

2. What is the primary function of the optic nerve?

Transmission of visual information from the retina to the brain.

3. What is the functional classification of the optic nerve?

Special somatic afferent (SSA).

4. Which retinal neurons give rise to optic nerve fibers?

Retinal ganglion cells.

5. Where do retinal ganglion cell axons converge to form the optic nerve?

At the optic disc, also called the optic nerve head.

6. Why does the optic disc produce a physiological blind spot?

It contains no photoreceptors.

7. Why is the optic nerve considered a central nervous system tract rather than a typical peripheral nerve?

It develops from the diencephalon and is myelinated by oligodendrocytes.

8. What are the four anatomical segments of the optic nerve?

Intraocular, intraorbital, intracanalicular, and intracranial segments.

9. Why does the intraorbital optic nerve follow a slightly curved course?

Its redundancy permits eye movements without excessive traction on the nerve.

10. Through which opening does the optic nerve enter the cranial cavity?

The optic canal of the sphenoid bone.

11. Which major artery accompanies the optic nerve through the optic canal?

The ophthalmic artery.

12. Which meningeal layers surround the optic nerve?

Dura mater, arachnoid mater, and pia mater.

13. How does the optic nerve subarachnoid space relate to the cranial subarachnoid space?

They are continuous, allowing intracranial pressure to be transmitted around the optic nerve.

14. What structure is formed by the convergence of the right and left optic nerves?

The optic chiasm.

15. Which retinal fibers cross at the optic chiasm?

Fibers originating from the nasal halves of both retinas.

16. Which retinal fibers remain uncrossed at the optic chiasm?

Fibers originating from the temporal halves of both retinas.

17. Which visual field is represented in the right optic tract?

The left visual hemifield of both eyes.

18. Where do most optic tract fibers terminate?

In the lateral geniculate nucleus of the thalamus.

19. Which pathway carries visual information from the lateral geniculate nucleus to the primary visual cortex?

The optic radiations, also called the geniculocalcarine tract.

20. Where is the primary visual cortex located?

Along the calcarine sulcus of the occipital lobe.

21. Which midbrain region receives retinal input for the pupillary light reflex?

The pretectal area.

22. What is the role of the optic nerve in the pupillary light reflex?

It forms the afferent limb, carrying light-related sensory signals from the retina.

23. Which artery supplies the inner retina and travels within the optic nerve?

The central retinal artery, a branch of the ophthalmic artery.

24. What is the principal arterial supply of the anterior optic nerve head?

Branches of the short posterior ciliary arteries.

25. Which vein drains the retinal circulation through the optic nerve?

The central retinal vein.

26. What visual defect results from complete destruction of one optic nerve?

Complete blindness in the ipsilateral eye.

27. What visual field defect typically results from compression of the central optic chiasm?

Bitemporal hemianopia.

28. Which pituitary region tumor commonly compresses the optic chiasm?

A pituitary macroadenoma extending superiorly from the sella turcica.

29. What is papilledema?

Swelling of the optic disc caused by increased intracranial pressure.

30. What pupillary finding may indicate a unilateral optic nerve lesion?

A relative afferent pupillary defect, detected using the swinging flashlight test.