Nervous System

º acts like internet- receives and responds to information º two divisions º central º peripheral

A change in an organisms environment (internal or external)

º A reaction or behavior to a stimulus º involuntary or voluntary

º nerve cell º carries information

Contains nucleus and dendrites

Receive nerve impulses

Message that a neuron carries

º picks up stimuli and changes it to a nerve impulse º nerve impulse travels to a interneuron

They are found between sensory and motor neurons

º sends impulses to muscles and glands º respond

Sends nerve impulses away from cell body º one way street º only one per neuron

º protective covering of axon º helps messages send faster

º receive messages from axon º send messages to other neurons

A gap between the dendrites of one neuron and the axon tips of another

The chemical form of electrical nerve impulses

º 2 major structures Brain Spinal chord º directs movement

Consists of nerve fibers that branch off to the rest of the body

Voluntary movements Ex: eating and writing

Involuntary movements Ex: digestion and breathing

º prevent pain and injury º autonomic response- occur w/o thinking º bypass the brain