THE EYE CELLS

How To Create A Unit Inspired By The Eye Cells

How To Create A Unit Inspired By The Eye Cells

Above is a diagram of the eye, it shows all of the major components. Now, here is some more information about the function of some of the individual parts labeled. Choroid This is a layer in the eye's membrane that contains the blood vessels. It is also pigmented a dark colour so that there is as little light interference in the eye as possible. The layer above this is the sclera which is an outside layer protecting the eye. The iris consists of muscles that act to adjust the amount of light entering the eye by the size of the pupil. Cornea. This is a transparent part of the sclera where light enters, it is curved to help focusing by refraction. Lens. This is a biconvex disc, so that light converges on to the retina. It's shape can be adjusted by the cilliary muscle to allow focusing on near and far objects. Retina, this is a light sensitive area at the back of the eye that detects light and sends signals to the brain. (Curcio, 1990: 497-523)

The iris controls the amount of light that enters the eye by contraction and relaxation of the radial and circular muscles in the iris. This increases the size of the pupil so more light enters when it is dark and the reverse in light conditions. Another way the eye must adjust the light is by accommodation, or focusing; it does this by refraction. Every part of the eye refracts (or bends) light by different amounts. Most refraction occurs in the cornea, because it is curved. However this only every by the same amount, therefore we adjust the shape of the lens to vary the refractive index to focus light on the retina.The table below outlines the eye's responses to focusing on different objects.

In the retina are cells responsible for detecting light, and sending this information to the brain. There are two types of cell, the rod and cone. Below is the structure of a rod cell, however the cone cell has the same features labeled, but is differently shaped.

Rod cells are responsible for detecting light/dark. They contain a pigment called rhodopsin. When light shines on this pigment, it is broken into the two proteins: retinal and opsin in a process called bleaching, this stimulates an action potential that is detected in the brain. However, the rhodopsin is very sensitive to light, and is therefore best in dim conditions; since in brighter conditions it is broken down faster than it is reformed. (Curcio, 1990: 497-523) This is why, in dim conditions we will see mainly in black and white. The cone cell has a different pigment called iodopsin. There are three different types of this pigment: each sensitive to either red, blue or green wavelengths of light. Therefore we have red, green and blue cones. It is possible to see different colours by the stimulating ...