Eye and Brain
- Created by: Slartibartfast2
- Created on: 06-09-17 19:03
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- The Eye and the Brain
- The Brain
- Parts of the Brain
- Cerebral Cortex - The wrinkly bit on the outside of the brain. Controls language, memory and all other conscious actions.
- Medulla - Controls uncosconscious actions like heartbeat.
- Cerebellum - Coordinates muscles.
- Ways of Studying
- Observing people with brain damage - You can tell that a section of the brain controls somthing if someone without it can't do certain things.
- Stimulating the Brain electrically - If a certain bit of the brain is stimulated, it causes and effect, you can tell that the stmulated section of the brain controls that effect.
- MRI Scans - Scans can show which parts of the brain are active when a person does somthing. The action is controlled by the active part.
- Parts of the Brain
- The Eye
- Parts of the Eye
- Sclera - Tough outer wall of the eye.
- Cornea - transparent outer layer at the front of the eye. It refracts light into the eye.
- Iris - contains muscles (circular and radial) that change the size of the pupil.
- Lens - focuses light onto the retina.
- Retina - Light sensetive area at the back of the eye. Contains special cells to detect light intensity and colour.
- Ciliary muscles and Suspensory Ligaments - Control the shape of the lens.
- Optic Nerve - Takes impulses from the retina to the brain.
- Iris Reflex
- To protect the retina from damage caused by bright light, the circular muscles contract and the radial muscles relax to make the pupil smaller in bright light. This reduces the amount of light entering the eye. The opposite happens in dim light.
- Foccusing Light
- Near Objects
- The Cilliary Muscles contract, which slackens the suspensory ligaments. The lens becomes fatter. This causes it to refract light more.
- Far Objects
- The cilliary muscles retract, which tightens the suspensory ligaments. This makes the lens thin. This makes it refract light less.
- Near Objects
- Vision Defects
- Hyperopia (Long Sightedness)
- Unable to focus on near objects because the images focus behind the retina.
- Can be corrected using glasses with a convex lens. The light rays are refracted, so the focus on the retina.
- Myopia (Short Sightedness)
- Unable to focus on distant objects, because the images focus in front of the retina.
- Can be corrected using glasses with a concave lens. The light rays are refracted, so the focus on the retina.
- Hyperopia (Long Sightedness)
- Parts of the Eye
- The Brain
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