Last - Function And Locations Of The Parts Of The Eye Flashcards
Commonly called the “white” of the eye. A tough, tendon-like layer continuous with the dura mater of the brain around the optic nerve. It shapes the eye and is the insertion pint for the six muscles which controls eye movements.
Sclera
The most anterior layer of the eye that is continuous with the sclera. Transparent to allow light into the eye. Well supplied with nerve endings for pain, reflex blinking, and to stimulate lacrimal secretions. It also lacks blood vessels.
Cornea
Separates the fibrous and sensory tunics. Contains a dense capillary bed that provides oxygen and nourishment to the eye. Also contains many melanocytes which give its dark appearance.
Choroid
Lies just beneath the cornea. The layer to which we attribute eye color. Composed of two layers of pupillary muscles that control diameter of the pupil, and thus the amount of light entering the eye.
Iris
This is the round central opening in the center of the eye.
Pupil
A thick ring of tissue attached to, and lies just beneath the iris. Anchored at its margins by the choroid. Holds the lens in place beneath the iris and centered in the pupil. Contains the ciliary muscle, a smooth muscle that attaches to the lens. Changes the lens shape to focus light onto the retina.
Ciliary body
Located beneath the iris and held in center of the pupil by suspending ligaments extending from the ciliary body. Transparent and convex on its outer and inner surfaces. Focuses an image on the retina by changing shape under the influence of the ciliary muscles.
Lens
The delicate, two innermost layers of the eye. The neural layer contains photoreceptors and neurons that react to light and transmit and integrate visual signals. Beneath the neural layer lies the pigmented layer. It absorbs light that has passed through the neural layer to prevent the light from bouncing back and causing “visual echoes”.
Retina
Photoreceptors cells very sensitive to light. They enable us to see shades of gray in dim light.
Rods
Photoreceptors cells responsible for high acuity color vision. They only operate in bright light. There are three types: sensitive to red, green, or blue light.
Cones
Synapse with the dendrites of the rods and cones. They transmit nerve impulses to the ganglion cells.
Bipolar neurons
Synapse with the axons of the bipolar neurons. The axons combine to from the optic nerve, which sends nerve impulses to the brain.
Ganglion cells
Where the optic nerve leaves the eye. Not covered by the retina. A blind spot in the eye.
Optic disc
Cranial nerve II: it transmits visual information from the eye to the brain.
Optic nerve
