Structure and Function of the Eye
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The human eye allows for vision through a complex set of interacting structures. Light enters through the clear cornea and pupil, and is focused on the retina. The retina contains light-sensitive rod and cone cells that convert the light image into electrical signals transmitted by the optic nerve to the brain for processing and perception of vision. Key structures like the iris, sclera, cornea, lens, retina and optic nerve work together to allow light to enter the eye, focus the image, and transmit visual information to the brain.
Structure and Function of the Eye
- 1. Structure and Function of the Eye
- 2. Human Eye : The human eye is an organ which reacts to light and pressure. As a sense organ, the mammalian eye allows vision. A Normal Eye looks like,
- 3. Parts of Human Eye The front part of the Eye includes: Iris: the colored part. Cornea: a clear dome over the iris. Pupil: the black circular opening in the iris that lets light in. Sclera: the white of your eye.
- 4. Eye Anatomy
- 6. Cornea CORNEA (clear lens in front of eye) transparent covering of the front of the eye Allows for the passage of light into the eye and functions as a fixed lens. Function: Allows for the passage of light into the eye and it also focuses the light.
- 7. Pupil PUPIL (black hole) black hole in iris where light enters Function: Pupil size is controlled by iris muscles
- 8. Pupil Expansion When the eye needs more light to enter (when it is dark), the pupils get larger; allowing more light to enter the eye
- 9. Pupil Contraction When the eye needs less light to enter (when it is very bright), the pupils get smaller; allowing less light to enter the eye.
- 10. Sclera SCLERA – a tough white skin (made of tissue) that covers all of the eyeball except the cornea. Function: Supports eyeball and provides attachment for muscles
- 11. Retina Internal membrane Contains light-receptive cells (rods and cones) Converts light to electrical signals Function: Converts light waves to electrical signals
- 12. Optic Nerve OPTIC NERVE Transmits electrical impulses from retina to the brain Creates blind spot Brain takes inverted image and flips it so we can see Function: Transmits electrical signals from retina to the brain
- 13. Blind spot (Optic disk illustration ) Close your right eye and look directly at the number 3. Can you see the yellow spot in your peripheral vision? Now slowly move towards or away from the screen. At some point, the yellow spot will disappear.
- 14. Functions Cont. The eye has many parts that must work together to produce clear vision: The sclera, or white part of the eye, protects the eyeball. The pupil, or black dot at the center of the eye, is a hole through which light can enter the eye. The iris, or colored part of the eye, surrounds the pupil.
- 15. The Refractive Structures These structures bend the light so that a clear image is produced. They are: tears cornea lens
- 16. Lids and Lashes Main function is the protection of the eye. They also help to distribute tears which wash and lubricate the eyes.
Editor's Notes
- #16: Three chambers in the eye 1. Anterior chamber – from cornea to iris 2. Posterior chamber – from iris to zonules and lens – These two are responsible for the production and drainage of the aqueous which is produced continuously throughout your life produced in the posterior chamber by the ciliary body travel through the iris to drain out the anterior chamber (through the Canal of Schlemn) 3. Vitreous – gel like –gives the eye its shape not produced – damage or loss can cause retinas to fall or tear