Transcript external stimuli

Nervous System
http://www.brainpop.com/health/bodysystems/nervoussystem/
Structures of the nervous system
• The nervous system is made up of the
brain, spinal cord and nerves.
• The central nervous system (CNS)
consists of the brain and spinal cord.
• The peripheral nervous system (PNS)
consists of all nerves outside of the
central nervous system.
Function of the nervous system
The nervous system functions
1. to receive information
2. respond to stimuli
3.to maintain stable internal
conditions.
Receiving Information
• Your nervous system
makes you aware of what
is happening in the
environment around you.
• It lets you know that a ball
is zooming toward you,
your favorite song is on
the radio and that the
pizza in your hand is hot.
• Your nervous system also
checks conditions inside
your body, like glucose
levels in your blood.
Responding to Stimuli
• The nervous system
responds to external
stimuli like laughing at
a funny movie.
• The nervous system
also responds to
internal stimuli such
as the body’s need for
more oxygen by
increasing the heart
rate.
Maintaining Stable Internal
Conditions
• The nervous system
helps the body to
maintain homeostasis by
directing the body to
respond appropriately to
the information it
receives.
• For example, when you
are hungry your nervous
system directs you to eat.
The Three Parts of the Brain
are:
• Cerebrum
Interprets input from
sense organs,
controls voluntary
movement, and is
responsible for
learning and memory.
http://www.brainpop.com/health/bodysystems/brain/
Cerebellum
Coordinates your
muscle
movements and
helps you keep
your balance.
Brainstem
Controls
involuntary actions
such as your
heartbeat,
breathing and
reflexes.
Cerebrum
Brainstem
Cerebellum
http://www.brainpop.com/health/bodysystem
s/spinalcord/
Neurons- nerve cells
• Neurons are cells that carry information through
your nervous system.
• The information is carried in what is called a
nerve impulse.
http://www.brainpop.com/health/bodysystems/neurons/
Three Types of Neurons
• Sensory Neurons
Pick up stimuli
from internal or
external
environment and
converts it to an
impulse.
Motor Neurons
• Send an impulse
to a muscle, and
the muscle
contracts in
response.
Interneuron
Located in the
brain or spinal
cord and carries
the nerve
impulse from one
neuron to
another.
Reflexes
• A reflex is an automatic response that
occurs very rapidly and without conscious
control.
• The contraction of skeletal muscles is
usually controlled by the brain, but in
reflexes the muscles react with the
involvement of the spinal cord only – not
the brain. This protects us from danger.
• http://faculty.washington.edu/chudler/chga
mes.html
• http://faculty.washington.edu/chudler/word
s.html
Sources:
•
http://www.georgiapainphysicians.com/l2_edu_pharma_mod1_slides.htm
•
http://www.omsusa.org/pranzatelli-Brain.htm
•
http://www.unitedstreaming.com