Transcript The Nervous System

Nervous System
Function
Allows your body to react to your
environment and stimuli.
Organs
Brain
Spinal cord
Nerve cells (neurons)
Brain
Coordinates all of your body’s activities
3 parts: cerebrum, cerebellum, brain stem
Cerebrum
Cerebellum
Brain Stem
https://
www.yo
utube.c
om/wat
ch?v=r
SQNi5s
Awuc
Spinal cord
43 cm long and the diameter of your thumb
Made of bundles of neurons to carry signals
to and from the brain from the rest of the
body.
Neurons
Parts:
– Cell body
– Dendrites (receive input)
– Axons (deliver message)
Direction of message
How it works
Nerve
Messages
Messages sent through a
synapse (gap)
https://www.youtube.com/
watch?v=p5zFgT4aofA
https://www.youtu
be.com/watch?v=
WhowH0kb7n0
Messages move along neurons like batons
in a relay race to spine, brain, and back
120 meters/second
These signals can continue to
work even if the brain is not
sending the signal
https://www.youtube.com/watch?v=2YZJt_
Bw3eo (twitching frog legs)
https://www.youtube.com/watch?v=rSQNi5
sAwuc (TED talk- control someone else’s
arm with your brain)
Reflex
Involuntary, automatic response to a
stimulus (hot, cold, sharp)
They can’t be controlled because they
occur before you know what happened.
Reflex responses are controlled by spinal
cord, not brain = faster response
Examples of reflexes
Blinking, sneezing, knee tap, flinching, etc.
diving, grasping, and moro (in babies)
Diving
Drug Effects
Depressants (alcohol and
marijuana) – slow your nervous
system response time
Stimulants (caffeine and
methamphetamines) – speed up
activity
https://www.youtube.c
om/watch?v=4spIzhl2c
GE
review
https://www.youtube.com/watch?v=jJfESat
tZOY