1. The Nervous System

2. Interesting Facts
Each side of the brain controls the opposite side of the body.
Your brain is full grown by age 6-7 (in size).
It weighs about three pounds.
Your brain is made mostly of water. (85%)

3. Healthy Habits Exercise Do challenging activities that make you think
read, read, read
Lift things carefully – use your legs, not your back

4. What are the functions of the NS?
Collects information about the body’s internal and external environment
Processes that information
Responds to it

5. Your nervous system has two divisions…
Peripheral Nervous
System
Central Nervous
System
Spinal
cord
Brain
Links the
CNS to
body
12 pairs of
Cranial nerves
Surrounded by bones
Somatic
Autonomic

6. Gathers info and sends it to the CNS Searching for a pen in your bag…
PNS
Gathers info and sends it to the CNS
Searching for a pen in your bag…
PNS
Gathers info from hand
Input
CNS
Processes the info and forms a response
CNS
YES? Pen found
NO? Pen not found
Output
PNS
Carries the response to glands and muscles
PNS
Keep searching
Stop Searching

7. How does this communication work?
The messages are carried by electrical signals called
These impulses are transmitted by cells called
IMPULSES
NEURONS

8. 3 Types of Neurons Specialized in location and structure Sensory
- carries impulses from the sense organ (hand) to CNS
Interneuron
- conducts impulses between sensory and motor
Motor
- carries impulses from brain + spinal cord to muscles and glands

9. sensory neuron
motor neuron
interneuron

11. Structure of a Neuron dendrites Cell body Nucleus of schwann cells
Node of ranvier
Node of
Ranvier
axon
Axon terminals

12. Function of the neuron parts:
Cell body – contains nucleus, receives signals from other neurons,
Axon – conducts nerve impulses away from the cell body
Axon terminal – end of the axon
Node of ranvier – gaps where there is no myelin sheath
Schwann cells – forms the myelin sheath
Dendrites – extensions leading toward the cell body

13. Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.
Bill Watterson, cartoonist, "Calvin and Hobbes" US cartoonist ( )