The Human Eye
The anterior chamber lies between the iris and the back surface of the cornea. There are three chambers of fluid in the eye. The anterior chamber, which is between the cornea and iris. The posterior chamber, which is between the iris and lens. And, the vitreous chamber, which is between the lens and the retina. The fluid filled substance is called the aqueous humor. It is a clear fluid that fills the anterior chamber and the posterior chamber of the anterior cavity of the eye. The aqueous humor bathes the lens and gives nourishment to the lens. The aqueous humor is produced by the ciliary body. {draw:frame}
{draw:frame} The colored part of the eye is called the iris. It controls light levels inside the eye similar to the hole on a camera. The round opening in the center of the iris is called the pupil). The iris is embedded with tiny muscles that dilate (widen) and constrict (narrow) the pupil size. The sphincter muscle lies around the very edge of the pupil. In bright light, the sphincter contracts, causing the pupil to constrict. The dilator muscle runs radically through the iris, like spokes on a wheel. This muscle dilates the eye in dim lighting. The iris is flat and divides the front of the eye (anterior chamber) from the back of the eye (posterior chamber). Its color comes from microscopic pigment cells called melanin. The color, texture, and patterns of each person's iris are as unique as a fingerprint. The pupil is the black circle in the center of the iris. But, the pupil is really a clear opening. The pupil appears black because the light which the pupil allows to enter the eye is absorbed on the retina and does not exit the eye. Light enters the eye through the cornea; it then travels through the opening called the pupil. Light then enters the eye's lens. The pupil changes size in order to adapt to the quantity of light rays that reach it. The pupils constrict in response to increased light, this makes your pupils smaller. When the pupils are smaller, it allows in as little light as possible. The pupil dilates in response to decreased light, this makes your pupils larger. When the pupils are larger, it allows in as much light as...
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