Posted by lae2 on October 10, 2011 at 14:22:34:
Orbit and Globe - Learning Objectives and Review Questions
True/False
True/False - October 08, 2011 - Dr. Quillen
1. The lens provides 66% of the refractive index of the globe and the cornea provides 33%.
2. The orbital septum separates the region of the face from the orbit.
3. The upper medial superior conjunctival fornix receives tears from the ducts of the lacrimal gland.
4. The eyelids play a critical role in protecting the eye.
5. The meibomian glands secrete tears in response to irritation and the lacrimal gland secretes tears to assure lubrication.
6. The meibomian glands are also known as the tarsal glands.
7. The lacrimal gland is mostly involved with reflexive tearing and the accessory lacrimal glands are primarily responsible for tear film.
8. The vascular tone of the conjunctiva, if low, leads to conjunctival injection (red eye).
9. Loss of sympathetic tone to the orbit is a cause of conjunctival injection.
10. Conjunctival injection is a symptom of Horner's syndrome.
11. Total refraction of the eye is 1/3 by cornea and 2/3 by lens.
12. Flattening the cornea changes the refractive properties of the eye.
13. The corneal arterial plexus is derived from the lacrimal artery.
14. End arteries feed the cornea and blockage of these arteries leads to corneal necrosis.
15. The pain of corneal abrasions is minor because the neural supply to the cornea is slight.
16. The primary sensory cell bodies that mediate corneal pain are located in the geniculate ganglion.
17. The primary sensory cell bodies that mediate the afferent limb of the blink reflex are located in the nodose ganglion.
18. The ciliary muscle pulls on the zonule fibers and, thus, allows the lens to thicken and provides accommodation.
19. The central retinal artery provides the arterial supply to the lens.
20. A lesion of the superior division of the oculomotor causes a failure to accommodate.
21. The vitreous makes up about 80% (4/5) of the volume of the eye.
22. The optic disc is the region of the retina having the highest visual acuity.
23. The macula of the retina is devoid of receptors and is responsible of the blind spot of the visual field.
24. The foveal avascular zone enhances the acuity of foveal vision because larger vessels are not present.
25. Approximately 1.2 million nerve fibers make up the SSA component of the optic nerve.