The Eye – Its Anatomy and Physiology -- Lesson 261
Light rays pass through the dark center of the eye, called the pupil. The mucous membrane which is called the conjunctiva that lines the eyelids and coats the front portion of the eyeball over the white of the eye. The conjunctiva is very blur and colorless except when blood vessels are dilated. Dust or smoke may cause to dilate the blood vessels and give the conjunctiva an appearance of red which is generally known as bloodshot eyes. The cornea which is a fibrous, transparent tissue that extends over the pupil and colored eye portion. The cornea works as it bend, or refract, the rays of light; so that they are indented properly on the cells of the sensitive receptor in the region of the eye which is posterior. The cornea is a vascular which has no blood vessels but receives its nourishment from blood vessels near its junction with the white of the eye, the selera. For people with scarred or opaque corneas are successful corneal transplants because the cornea has no supply of blo