Transcript The Nervous System

The Nervous System
Miss Charney
Northville Central School
Nervous System Functions
 Receives information about
what is happening to your
body
 Stimulus - change or signal
that makes the body react
 Directs the way in which
your body responds to the
information
 Response - what your body
does in a reaction
Neurons
 Cells that carry information
through your nervous system
 Nucleus - directs the actions
of the neuron
 Dendrites - carry impulses
toward the neuron’s cell body
(can have many)
 Axon - carries impulses away
from the cell body (can have
only one)
Types of Neurons
 Motor Neuron: sends impulses to a
muscle or gland
 Sensory Neuron: picks up stimuli
from the internal or external
environment and converts the stimulus
into a nerve impulse
How An Impulse Travels
 Synapse: the junction where one
neuron can transfer an impulse to
another
How An Impulse Travels
How An Impulse Travels
1.
2.
3.
4.
5.
6.
Nerve impulses begin when receptors pick
up stimuli from the environment
Receptors trigger nerve impulses in sensory
neurons
Nerve impulses pass to interneurons in the
brain
Your brain interprets the impulses
Impulses travel along thousands of motor
neurons
Motor neurons send the impulses to
muscles, which carry out the response
Parts of the Nervous System
Central Nervous System
 Control center of the body
 Brain: located in the skull,
is the part of the CNS that
controls most functions in
the body
 Spinal Cord: thick column
of nervous tissue the links
the brain to most of the
nerves in the peripheral
nervous system
Parts of the Brain
 Cerebrum: largest part
of the brain
 Interprets input from the
senses, controls movement,
and carries out complex
mental processes such as
learning and remembering
 Left half - mathematical
skills & logical thinking
 Right half - creativity &
artistic ability
Parts of the Brain
 Cerebellum: second
largest part of the brain
Coordinates actions of
your muscles and helps
you to keep balance
Parts of the Brain
 Brain Stem: between
the cerebellum and the
spinal cord
Controls your body’s
involuntary actions such
as breathing and heart
rate
Peripheral Nervous System
 network of nerves branching
out from the CNS and
connect to body
 Somatic Nervous System:
control voluntary actions
such as using a fork or tying
your shoes
 Automatic Nervous
System: control involuntary
actions
Reflexes

Automatic response that occurs
very rapidly and without
conscious control

Reflex Pathway:
1.
2.
3.
4.
Sensory neurons in your fingertip
detect a pain stimulus
Nerve impulses travel to your
spinal cord
Nerve impulses return to motor
neurons in your hand, and you
pull your hand away
As you pull your hand away,
nerve impulses travel to your
brain. You feel the pain