Eye Anatomy Flashcards
Anterior Chamber
The area inside the eye, BEHIND the cornea, and IN FRONT of the iris. This area is filled with clear, watery fluid called aqueous humor.
Aqueous Humor
A clear, watery fluid produced by the ciliary body. It fills the front part of the posterior chamber and the entire anterior chamber. Provides nutrients for the lens and posterior cornea and carries away waste products. Responsible for maintaining the intraocular pressure because it is the only fluid continually produced in the eye.
Choroid
The choroid consists primarily of blood vessels that nourish the retina so that it can continue to function. It is sandwiched between the sclera and the retina.
Melanin in the choroid absorbs excess light, which prevents reflection and scattering of light within the eyeball.
Ciliary Muscle
The muscle inside of the eyeball that alters the shape of the crystalline lens. It has direct control over the focusing ability of the eye (accommodation).
Conjunctiva
The clear, cellophane-like tissue that covers the sclera and the inside surface of the eyelids. The palpebral conjunctiva lines the lids, while the bulbar conjunctiva covers the sclera.
Cornea
The clear, transparent tissue that is located on the very front (anterior) portion of the eye. The cornea provides the major refractive (focusing) power of the eye. It has a curvature somewhat greater than the rest of the globe.
The cornea has five layers. They are, from front to back: epithelium, Bowman’s layer, stroma, Descemet’s membrane, and endothelium. The cornea is avascular (having no blood vessels)
Crystalline Lens
Provides focusing power to the eye. It allows adjustment of the eye to focus from distance objects to near objects. It is the second most powerful refractive medium.
Iris
Colored part of the eye. The iris consists of two circular muscles with a hole in the middle, called the pupil. The iris sphincter and dilator muscles control the size of the pupil for maximum visual performance.
Crystalline Lens
Provides focusing power to the eye. It allows adjustment of the eye to focus from distance objects to near objects. It is the second most powerful refractive medium.
The resilient, transparent structure in the eye that focuses light by changing curvature of its front surface. It is located near the front of the eye, directly behind the pupil.
Optic Disc
The appearance of the optic nerve when viewed through the pupil. The portion of the optic nerve that is formed by the meeting of all the retinal nerve fibers. It is not sensitive to light and corresponds to the physiological blind spot. The appearance of the optic disc can be used to determine the healthiness of the nerve itself.
Optic Nerve
Nerve that carries impulses from the retina to the brain. It transmits the signals from the rods and cones in retina to the brain.
This is the pathway between the eye and the brain along which the signals produced by the retina travel to the brain.
Orbit
Bony socket that contains the eye and most of its accessory organs. The roof, medial wall, and floor are very thin and can be easily damaged by injury, infection, or tumors.
For example, a blowout fracture, which occurs in the orbit floor, can be caused by blunt trauma and may cause the eye to appear sunken.
Posterior Chamber
Area located inside of the eye, BEHIND the iris, and IN FRONT of the lens.
Pupil
Round hole in the center of the Iris through which light passes. The pupil ordinarily appears black because there is very little light coming from the dark chamber behind it.
Retina
The light sensitive seeing part of the eye. The retina lines the sclera and is the place where light coming into the eye is focused. The images that fall on the nerve cells of the retina are then transmitted to the brain via the optic nerve, where they are interpreted.
The nerve center of the eye where light is converted into an electrical signal that travels along the optic nerve to the brain.
