Transcript The Nervous System

The Nervous System
What do these have in common?
• Tasting, smelling, seeing, hearing, thinking,
dreaming, breathing, heart beating, moving,
running, sleeping, laughing, singing,
remembering, painting, writing, feeling pain,
feeling sick.
What do these have in common?
• Tasting, smelling, seeing, hearing, thinking,
dreaming, breathing, heart beating, moving,
running, sleeping, laughing, singing,
remembering, painting, writing, feeling pain,
feeling sick.
• They are all controlled by your
CENTRAL NERVOUS SYSTEM!
The Nervous System
• Your brain and nerves (the nervous system)
regulates most body functions & responds to
the environment (through senses).
The Nervous System
• This is it. The human brain. About the size of
your fists put together, it stores everything
you have known or ever will know. Weird,
when you think about it.
Like a super-busy
telephone
switchboard, your
brain uses nerves
(think: wires of the
body) to receive and
send signals
CONSTANTLY.
The Nervous System: FUN FACTS
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The brain is composed of 85% water.
The brain uses 25% of the oxygen taken in by the body.
The average brain weighs 3 lbs.
The brain operates with the same electrical energy as a
10-watt light bulb.
Like a super-busy
telephone
switchboard, your
brain uses nerves
(think: wires of the
body) to receive and
send signals
CONSTANTLY.
The Nervous System
• Let’s start small and work our
way bigger…nerves are actually
a network of special support
nerve cells called neurons.
(think of them like switchboard
cells that make nerve wires)
• In regards to cells, neurons can
be huge…they can be wide
enough in diameter to be seen
without a microscope, and some
are almost 3 feet long!
Thick nerves seen here are
bundles of individual neurons.
The Nervous System
• Neurons aren’t programmed to die
like your other body cells…the
neurons you were born with are the
same ones you’ll have when you’re
89 years old. (Christopher Reeve)
Very few are made after the age of
about two.
• Using ions (electrically charged
atoms), neurons are able to pass
signals down their very long tails
(axons) at more than the length of a
football field per second. Yeah—
they’re fast. And weird looking.
The Nervous System
• As far as the spinal cord goes, it can do
a little thinking on its own, which is
why its considered a part of the CNS,
but its main job is to carry messages to
and from the brain.
• You already know how important it is
that your vertebrae successfully protect
your spinal cord. If not, it can be
injured permanently, with little or no
chance at recovery.
• Remember: Neurons aren’t
programmed to die like your other
body cells…the neurons you were born
with are the same ones you’ll have
when you’re 89 years old.
Functions of The Nervous System
• There are 3 Functions of the Nervous System:
• 1. SENSORY INPUT: When the eyes see or
hands touch, the neurons (nerve cells) send a
message to the brain.
• This action of getting information from the
surrounding environment to the brain by way
of the senses is called sensory input.
Functions of The Nervous System
• 2. INTEGRATION:
• Integration– The translation by the brain of
things that have been felt, tasted, and
touched with the sensory neurons into
responses that the body recognizes.
Functions of The Nervous System
• 3. MOTOR OUTPUT: Your brain sends a
message back through neurons to muscle or
other cells, which work to perform the
response.
How fast does an Impulse travel?
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Motor impulses travel at 119 m/s.
Sensory impulses travel at 76.2 m/s
Pain impulses travel at .61 m/s.
Not all impulses are the same.
• LINE UP!
The Nervous System
• The human nervous system is divided into two
different systems:
• The central nervous system
• The peripheral nervous system
The Nervous System
• If you ever hear of scientists/doctors on TV referring to the
CNS, they’re talking about the Central Nervous System.
• The CNS consists of the brain & spinal cord neurons. It’s
the “thinking/control” part of your nervous system.
• Functions:
• 1. Regulates bodily functions by sensing changes in
body/environment
• 2. Interprets changes & makes adjustments by
electrochemical impulses
• 3. These impulses result in muscular contractions
(like moving) or gladular secretions (like sweat)
CNS: Central Nervous System
PNS: Peripheral nervous system
• There are 2 types of neurons involved with PNS
• — Sensory neurons send information TO the
Central Nervous System (CNS) FROM internal
organs and from the environment
• — Motor neurons send impulses TO the
voluntary and involuntary muscles.
PNS: Peripheral nervous system
Motor neurons are divided into 2 types:
• Somatic Nervous System controls the skeletal
muscles and external sensory organs . This
system is voluntary. An exception is the reflex
reactions of skeletal muscle. (like shivering
when cold).
• Autonomic or Involuntary nervous system
controls involuntary muscles such as smooth
and cardiac muscle.
CNS & PNS
Nervous System: Problems
• (1.) A concussion happens when the skull
slams into the brain, “shocking” it. This
happens when the brain sits still due to inertia
(resistance to change), but a collision moves
the skull into the brain very quickly.
Sometimes this damage is minor, others for the
damage will affect them rest of their life.
Nervous System: Problems
• Here’s a truly sad and tragic one.
As some people age, their brain
cells stop communicating with
each other, causing memory
loss. This is known as
Alzheimer’s Disease.
President Ronald Reagan (1981-1989) &
Heston (Planet of the Apes, Ben-Hur,
• This almost always is found in Charlton
The Ten Commandments) both had this.
elderly people, and the cause is
not really well-understood.
There is no cure, and the only
treatment seems to be the
patience and understanding of
the sufferer’s loved ones.
Nervous System: Problems
• Imagine your hand shaking
uncontrollably…eating with a fork
or tying your shoes is so
frustrating and
uncomfortable…and
embarrassing.
Actor Michael J. Fox (Back to the Future) and
World Heavyweight boxer Muhammad Ali
• Eventually you have a hard time both have this.
making your mouth and tongue
form the sounds of words you’re
trying to speak. This is the effects
of Parkinson’s Disease.
• This is a disease caused by brain
damage that causes loss of
Nervous System: Problems
• If a blood clot blocks some areas of the
brain from getting oxygen, those cells
die. Well, they’re not replaced, so
whatever those cells used to control will
likely suffer from limited or nonfunction.
• This is a stroke – clot in a brain blood
Kirk Douglas (Spartacus & Michael
vessel…can cause death of brain tissue. Actor
Douglas’ dad) and Radio/TV host Dick Clark
(New Years) have both suffered strokes.
• Strokes are very serious, and can
definitely be life threatening.
• People who survive strokes may have
one side of their face “droop” or slurred
speech since they can’t control the
muscles there anymore.
Nervous System: Problems
• You really only get one brain. There’s no brain
“transplant” either.
• When you kill those brain cells, they don’t
magically repair them- selves, usually. So TAKE
CARE OF IT! Think of Ozzy!
Slksd asl sdkla dnndng ngnang
Snd ansdndn ansdsuwe sld
Stay off the drugs, kids! Lsdkal
Dsklsjdj djannd ehenan engna
Ennq ueueusn dndns andooop
Sndnda ndnnnnngggnn
3 Functions of the Nervous System:
1.
2.
3.
The Nervous System
Central Nervous System
Organs include:
Peripheral Nervous System
Type 1:
Does:
Type 2:
Does:
3 Functions of CNS:
1.
2.
Motor Neuron Type 1:
Def:
Motor Neuron Type 2:
Def:
Voluntary/Involuntary
Voluntary/Involuntary
3.
3 Functions of the Nervous System:
1. SENSORY INPUT: action of getting information from the surrounding environment to the
brain by way of the senses.
2. INTEGRATION: The translation by the brain of things that have been felt, tasted, and
touched with the sensory neurons into responses that the body recognizes.
3. MOTOR OUTPUT: Your brain sends a message back through neurons to muscle or other
cells, which work to perform the response.
The Nervous System
Central Nervous System
Organs include: BRAIN & SPINAL
CORD
3 Functions of CNS:
1. Regulates bodily functions by
sensing changes in
body/environment
2. Interprets changes & makes
adjustments by electrochemical
impulses
3. These impulses result in
muscular contractions (like moving)
or gladular secretions (like sweat)
Peripheral Nervous System
Type 1:Sensory neurons
DOES: send information
TO the Central Nervous
System (CNS) FROM
internal organs and
from the environment
Type 2: MOTOR
NEURONS
Does: send impulses TO
the voluntary and
involuntary muscles.
Motor Neuron Type 1:
Motor Neuron Type 2:
Somatic Nervous System
controls the skeletal
muscles and external
sensory organs .
Autonomic or Involuntary
nervous system controls
involuntary muscles such
as smooth and cardiac
muscle.
Voluntary
Involuntary