Opthamology lab Flashcards
What is the cornea? What is its function?
the transparent anterior refracting surface of the eye. It accounts for 2/3 of the refracting power of the eye (the lens accounts for the remaining 1/3)
What are the three histological layers of the cornea? What happens if each is damaged?
an outer epithelium, a collagenous stroma, and an inner endothelium. If abraded or infected, the epithelium will regenerate without harming vision. But if the stroma is damaged, a scar forms to distort and opacify the cornea and reduce vision
What is in the endothelium that keeps water out of the cornea? What happens if this is damaged?
The endothelium has a metabolic pump that keeps water out of the cornea in order to maintain transparency
When it is damaged, the cornea becomes edematous and loses transparency.
What are the boundaries of the anterior chamber?
bounded by the cornea in front and the iris-lens in back
Where does the water-like fluid in the anterior chamber come from?
Ciliary body
What happens to the anterior chamber when the iris becomes inflamed?
cells and protein leak into the aqueous to make it turbid (“flare”)
What is a hypopyon?
A collection of white cells in the anterior chamber of the eye when there is an infection
What is a hyphema?
Trauma to the blood vessels of the iris will result in blood pooling in the anterior chamber
What are the two muscles that comprise the iris? What is each’s innervation?
Circumferential = parasymp (M3) Radial = sympathetically (alpha 1)
What are the boundaries of the posterior chamber?
Iris in front and the anterior vitreous face in back
What is the conjunctiva? What are its two parts?
the mucous membrane covering of the anterior eye. It has two parts: the bulbar conjunctiva that covers the sclera, and the palpebral conjunctiva that covers the inner eyelids
True or false: the canal of Schlemm is rarely implicated in disease
True—trabecular meshwork is the site of obstruction in glaucoma
What are the components of the vitreous humor? (3)
hyaluronic acid, collagen fibers, and a dilute salt water solution
What are “floaters”?
the vitreous detaches itself from the optic disc, leaving a floater.
What is the macula?
Retinal region containing a high density of cones and ganglion cells specialized in visual acuity and color vision.
What is the fovea?
Central depression within the macula in which the retina consists only of cones.
What are the only cells that the retinal arteries nourish? Where are these arteries in relation to the retinal layer?
These vessels travel in the innermost retinal layer, and are visible through the ophthalmoscope. The arteries nourish only the retinal ganglion cells and their axons. The deeper layers of the retina get their blood from the choroid.
What is the retina?
The neural inner layer of the posterior part of the eye. It has a nutrient retinal pigment epithelial outer portion and a sensory inner portion.