The eye Flashcards
What is nystagmus and why does it occur?
the focusing of the eye to see close objects. It occurs after a chair spin because the eye can’t focus on any one object.
What are the 4 layers of the eyelid? What two muscles are found here?
- skin 2. muscles (orbicularis oculi and palpebrae superioris) 3. connective tissue 4. conjunctiva
What are the eyebrows for?
to keep sweat out of the eyes.
Where is the lacrimal gland and what does it do?
laterally superior to the eye, on the outside. It forms and drains tears.
Where do tears go when they leave your eyes?
through the puncta and canaliculi, where they drain into the lacrimal sac and into the nasolacrimal duct.
What kind of response are tears?
Parasympathetic
Superior rectus
up
inferior rectus
down
lateral rectus
out
medial rectus
in
inferior oblique
up, out, medial rotation
superior oblique
down, out, medial rotation
What cranial nerves innervate which extrinsic eye muscles?
Superior oblique-trochlear
lateral rectus- abducens
occulomotor innervates the others.
What is strabismus?
turned eye
What is phoria?
weakness of eye muscles
What are the 3 layers of the eye ball?
- fibrous tunic-avascular (cornea and sclera)
- vascular tunic-choroid, ciliary body, iris
- nervous tunic-photoreceptors
What are the two major functions of the ciliary body?
Make aqueous humor and accommodation
How does accommodation work?
the lens is stretched by the suspensory ligaments for close sight. The ciliary muscle contracts, releasing tension from the lens, making it thicker.
Where and how is aqueous humor produced?
ciliary processes make aq. humor in the ciliary body. Drains through the pupil.
What is glaucoma?
result of too much aqueous humor
Why is the lens clear?
it does not contain blood vessels.
What is a cataract?
when the lens becomes opaque
What are crystallins?
proteins in the lens
What does the iris do?
divides the anterior and posterior chambers
