Download Nervous System 4/28/09

Nervous System
05/28/2013
pages 163-164
Know: What are the 3 functions
of the nervous system?
Evidence: TB pg 633, draw, color,
and captions
Functions
1. Receiving info – inside and
outside body
2. Responding to info – reaction to
stimulus (change/signal)
3. Maintaining homeostasis
Process
Neurons (nerve cells) carry nerve
impulses (electrical or chemical
messages)
Process
Impulses begin in dendrite, move
toward cell body, then down axon.
Dendrite
Carries impulse toward cell body
Axon
Carries impulse away from cell body
(Draw picture/label below)
Axons & Dendrites
Process
Brain receives message and sends
impulses to muscles.
Impulses are passed from one nerve
to another or to an organ through
chemicals that jump the synapse (gap
between nerve cells)
Types
1. Central – control center of body,
brain and spinal cord
2. Peripheral – carries impulses
between central nervous system
and rest of body
- Somatic nervous system – controls
voluntary actions (texting)
- Autonomic n.s. – controls
involuntary actions (heart beat)
Reflex
Automatic involuntary response to
danger. Ex: your arm pulls back if
you touch something hot
Evidence & Summary
Evidence: TB page 633, Draw, label, color