Download Central Nervous System

Mr. Gibbons
7Acc Integrated Science
Name_________________________
Date___________________per____
The Nervous System
The control center of your body
Nervous System:
Body system that coordinates the actions of an animal and
transmits signals (impulses) to every part of the body
System overview:
(simplified)
Purpose?
 Coordinates _______________________________
controlling EVERY activity done
 Provides a means to send messages (impulses) to all parts of the
body from the brain
 Stores ________________ and allows for __________________
 Maintains ________________________
Reminder:
This system functions using a quick STIMULUS  RESPONSE scheme
The Organs:
The Picture:
Central Nervous
System
(CNS)
Brain (A)
&
Spinal Cord (B)
Peripheral Nervous
System
(PNS)
Nerves (C)
Note:
The average human brain is about 3.0 pounds and contains about
100.0 BILLION neurons (nerve cells)
Two parts of the nervous system:
Nervous
System
Central Nervous
System:
1.
Peripheral Nervous
System:
Central Nervous System (CNS)Control center of the nervous system controlling
both voluntary and involuntary processes
Voluntary –
Any process that occurs as a result of the organism thinking
about it (have control over)
Ex:
speaking, running, karate chopping
Involuntary –
Any process that occurs without any thought automatically
(have no control over)
Ex:
digestion, heartbeat, reflexes
A.
The Brain:
Large mass of neurons (nerve cells) located in the cranium and
divided into three main sections with their own functions.
Protected by the:
 Center for voluntary
activities
 Interprets messages
from sensory neurons
 Involves memory,
thought, and reasoning
o Controls involuntary
activities such as breathing,
heartbeat, peristalsis, and
blood pressure
 Coordinates motor activities
and maintains balance
B.
Spinal cord:
Bundle of nerves attached to the brain that runs down the
back. The spine is in charge of __________________________
Protected by the:
2.
Peripheral Nervous System (PNS)Consists of all of the ___________________ outside of
the central nervous system. These nerves coordinate
messages between all parts of the body and the central
nervous system (brain and spine)
The Nervous System Song
lyrics by: Mr. Parr
Each neuron has a cell body, a nucleus
Strands called nerve fibers
There are two types them
Carrying information out-in
When info's channeled to the cell body-Dendrites
When it is sent away from-axons
They pair up from one cell to a friend
To pass on the instructions
Chorus:
There are millions of nerves
They are called neurons
And there are just three types
Sensory is the first has receptors
They respond to stimuli
Association's in brain and spinal cord
Interpreting the info and passing on
To move the motor neurons carry to the body
Bring it to the glands
Bring it to the muscles...oh oh oh oh oh
Nervous System
Spinal cord, brain, and nerves... oh oh oh oh oh
The Nervous System
Nerves are chords that come in packs
Of nerve fibers
Sensory, motor, or mixed nerves
The spinal chord's a thick bundle runs from the brain
Through holes in the backbone
Info travels through electric signals nerve impulse
Neurotransmitter's released at the junction
If enough of the chemical builds up
In the next neuron
Impulse is sent on
Chorus:
There are two main types of actions, actions
Carried out your body, body
Voluntary actions, actions
Consciously in your mind, mind
If you do something, something
That is automatic, (that is automatic)
Involuntary action, (involuntary action)
Like digestion, breathing
Involuntary
Reflex actions are sudden movements
Chorus:
Everybody in the world, Let me here you sing it like
The Nervous System (spoken)
Neurons
Definition:
Three Types:
1.
Sensory Neurons –
Picks up a stimulus from a sense organ and carries a message
to the central nervous system (interneurons)
2.
Interneurons –
The “middle man” found only in the brain and spinal cord.
These neurons carry impulses between sensory and motor
neurons
3.
Motor Neurons –
Transfers impulses from interneurons to muscles and gland
telling them what to do
Neuron Parts
1
Dendrites
Cell Body
Carry impulses
_______________ the cell body
Core of the cell containing the
_________________
Axon
“Wire” that carries impulses
_______________ the cell body
Myelin
Sheath
Terminal
Branches
Neurotransmitter
2
3
Lipid covering the axon which
helps to ___________________
Releases neurotransmitters in
order to pass on the impulse
Chemical that travels over the
_________________
4
5
6
Other Vocabulary:
Impulse –
Electrical signal that travels through the nervous system from neuron to
neuron.
Synapse–
The space between the terminal branches of one neuron and the
dendrites of the next neuron
Refractory PeriodBrief period of time after an impulse has traveled through a
neuron where it cannot fire a second time (it must reset)
.
The Reflex Arc
It’s a no-brainer!
Hey, what
about me?
1.
Sensory organ is stimulated by some
stimulus
2.
The impulse is sent to interneurons in
the spine to be processed
3.
An impulse is sent to motor neurons
initiating a response (reaction)