The anatomy of the eye refers to the physical structures that form this important sensory organ. The human eye is an incredibly complex organ with a multitude of distinctive parts that make up its anatomy and with each performing a specific function. The term gross anatomy of the eye pertains to the structures that are visible when looking at an eye, and there are also many parts that can't be seen under normal circumstances. A few of the visible parts include the the cornea, iris, pupil, sclera, and conjunctiva; other internal structures include the lens, retina, and optic nerve. These structures work together to accomplish the task of receiving visual images and transmitting them to the brain.
The sense of sight is one that most people rely on heavily each day for a variety of activities such as reading, driving, operating a computer, and watching television. The many parts that make up the structure of the eye use incoming light to sense and process visual images and information. This information is then sent to the brain, which can interpret it and let the body know what it is seeing. Several structures included in the anatomy of the eye are very easy to see without the need for magnification or special instruments. This is called the gross anatomy of the eye and includes structures like the cornea, iris, pupil, and sclera.
The cornea is a transparent outer layer that has the dual purpose of protecting the inner parts of the eye and helping to focus images that are being viewed. Behind the cornea is the iris, which is the colored part of the eye, and the pupil which is the opening at the center. The iris controls the size of the pupil by expanding and contracting, and the pupil lets light through to the lens and interior portions of the eye. The sclera is the white part of the eye, which gives it shape and contains blood vessels that supply oxygen. The conjunctiva is a transparent mucous membrane lining the inside surface of the eyelid and covering the sclera; it keeps the surface of the eye moist and provides a layer of protection against pathogens.
Several other structures comprise the interior anatomy of the eye. The lens is a clear structure with a slightly flattened oval shape located behind the pupil and iris and is responsible for focusing the light that enters the interior of the eye. The retina is a layer of light sensitive cells on the back of the eyeball, and the image being seen is projected on it like a movie screen. The optic nerve connects the eye to the brain and carries the information about visual stimuli. There are also a variety of small muscles attached to the eye and eyelid that allow them to move.