NUR 300 Eyes
- External Eye
Answer -Inner and outer canthus
-Upper eyelid normally covers a portion of the iris
- Cranial Nerve II- Optic Nerve
Answer -The optic nerve is located in the back of the eye. It is also called the second cranial nerve or cranial nerve II. It is the second of several pairs of cranial nerves. The job of the optic nerve is to transfer visual information from the retina to the vision centers of the brain via electrical impulses.
-The optic nerve is made of ganglionic cells or nerve cells. It consists of over one million nerve fibers. Our blind spot is caused by the absence of specialized photosensitive (light-sensitive) cells, or photoreceptors, in the part of the retina where the optic nerve exits the eye.
- Eyelid
Answer *Components*
-Skin -Conjunctiva -Striated and smooth muscle
*Function* -Distribute and limit light
- tears
-Protect from foreign bodies
- Muscles of the eye
- 4 Rectus 1 / 2
Answer
-2 oblique
Enervated by CN III- Oculomotor, IV- Thochlear, VI-Abducens
- Ptosis
Answer When the upper eyelid droops
-Ptosis is a drooping of the upper eyelid. The lid may droop only slightly, or it may cover the pupil entirely. In some cases, ptosis can restrict and even block normal vision.
- Lacrimal Apparatus
Answer -Provides constant irrigation to keep the conjunctiva and cornea moist and lubricated.
*Lacrimal glands- in upper outer corner over the eye, secretes tears.
-The tears pass over the eyeball and enter two lacrimal ducts through the 2 lacrimal puncta, upper and lower lid on the inner canthus then into nasolacrimal duct.
- Meibomian glands
Answer -Secrete oily film that covers eyelid margins, continuous row on upper and lower lid-prevents overflow of tears.
-Helps form an airtight seal when lids are closed.
- Eyelashes
Answer Cilia that grow out of hair follicles along the margins of lids.
-curve outward
If you lose cilia=abnormal opening
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