Question

Draw a labelled diagram of the human eye. Explain the structure of the eye.

Answer 1

The eye consists of:

1. Eyeball: It is nearly spherical in shape. It preserves the shape of the eye and protects it from injury.
2. Eye lens: The eye lens is in the front of the eyeball. It makes a real and inverted image of the objects on the retina. It is held in its place by ciliary muscles attached to the eyeball.
3. Ciliary muscles: The ciliary muscles surrounding the eye lens can increase or decrease the thickness of the lens, thus making its focal length shorter or longer.
4. Retina: The retina is a thin tissue that has many layers of cells. It consists of nerve cells that are sensitive to the brightness as well as to the colours of light. The nerve cells carry messages about the image from the retina to the brain in the form of special signals. The brain then interprets these signals and enables us to see the objects.
5. Iris: Iris is the coloured part of the eyes. It controls the amount of light that can pass through the eye lens to the retina.
6. Pupil: The dark spot in the center of the iris is called the pupil. The pupil is the opening of the eye.
7. Cornea: It is a thin layer of transparent material covering the iris. The main function of the cornea is to protect the eyes. It also helps in focusing light.