The Eye

If I had to choose my favorite body part it would be the eye. Eyes are organs that detect light. Different kinds of light-sensitive organs are found in a variety of animals. The simplest eyes do nothing but detect whether the surroundings are light or dark, which is sufficient for the entrainment of circadian rhythms but can hardly be called vision. More complex eyes can distinguish shapes and colors. Your eyes are at work from the moment you wake up to the moment you close them to go to sleep. They take in tons of information about the world around you shapes, colors, movements, and more. Then they send the information to your brain for processing so the brain knows what's going on outside of your body. The eye is about as big as a ping-pong ball and sits in a little hollow area in the skull. The front part is protected by the eyelid. The eyelid helps keep the eye clean and moist by opening and shutting several times a minute. This is called blinking, and it's both a voluntary and involuntary action, meaning you can blink whenever you want to, but it also happens without you even thinking about it. The white part of the eyeball is called the sclera. The sclera is made of a tough material and has the important job of covering most of the eyeball. Think of the sclera as your eyeball's outer coat. Look very closely at the white of the eye, and you'll see lines that look like tiny pink threads. These are blood vessels, the tiny tubes that deliver blood, to the sclera. The cornea, a transparent dome, sits in front of the colored part of the eye. The cornea helps the eye focus as light makes its way through. It is a very important part of the eye, but you can hardly see it because it's made of clear tissue. Like clear glass, the cornea gives your eye a clear window to view the world through.