The Central Nervous System

• The CNS can easily be damaged by disease or injury, if this happens your normal system for responding to change is disturbed and the result could be inappropiate responses or even no response at all.

Different Parts of the Brain Process Different Information

• The cerebrum – the largest part of the brain. It coordinates sensory information and decides what the response should be ( it does the thinking).
•  Impulses from each sense organ go to a differnt part of the brain for processing.
• Information from receptors in the eye travels along a nerve to an area at the back of the cerebrum where the information is processed. thi area then sends a message to the motor area in the brain telling it how to respond.
• Knowing which bit of the brain processes what information is really useful for diagnosing brain damage. For example if a car crash victim has poor speech, you can tell the speech control area of their brain has been damaged.

Responses can be voluntary or involuntary ( reflex)

• Voluntary responses to a stimulus are responses that you consciously decide to do like running or speaking your brain has process the information and make decisions about how to respond.
• You alos have reflex or involuntary responses that respond to stimuli automatically.

Reaction Time is How Quickly You Respond

Reaction time is the time it takes to respond to a stimulus often less then a second.