Transcript The Nervous System

CHS AP Psychology
Unit 3: Biological Psychology
Essential Task 3-5b:Describe the subdivisions
and functions of the peripheral nervous system:
A. Somatic Nervous System
B. Autonomic Nervous System
– i. Sympathetic Nervous System (Fight or Flight)
– ii. Parasympathetic Nervous System (Rest and Digest)
The Central Nervous System
• The Brain
• The Spinal Cord
The Spinal Cord
• Complex cable of nerves that connects
brain to rest of the body
• Carries motor impulses from the brain
to internal organs and muscles
• Carries sensory information from
extremities and internal organs to the
brain
• 400,000 people a year in US either
partial or complete paralysis.
The Spinal Cord
• The spinal cord controls some
protective reflex movements without
any input from the brain
The Somatic Nervous System
• Consists of neurons that communicate
between the body and the brain
• Motor Neurons
– Neurons that carry messages from the
spinal cord (through interneurons) or
brain to muscles and glands
The Autonomic Nervous System
• Sympathetic division
– Most active when you
are angry, afraid, or
aroused
– Increases heart rate
and breathing
– Stops digestion
– “Fight-or-flight”
SNS = Evolutionary Byproduct
What “fear” looks like…
(Taken in a Haunted House)
A Sympathetic Nervous
System (SNS)
Response
Hold me!
Congo line of fear
Even Flannel Bros have an SNS
response
The “I’m not really here to protect
you;
I just happen to be in front”
response.
Fight, Flight and
“Freeze”?
The pupils don’t just dilate for
some people. The eyes widen, too!
The Autonomic Nervous System
• Parasympathetic
division
– Calms body
– Produces effects
opposite to those of
the sympathetic
division
– Reduces heart rate and
breathing
– Restores digestion
– “Rest and Digest”
The Hypothalamus Has Central
Control of the ANS
• When someone experiences a stressful event, the
amygdala, an area of the brain that contributes to
emotional processing, sends a distress signal to the
hypothalamus.
– This area of the brain functions like a command
center, communicating with the rest of the body
through the nervous system so that the person has
the energy to fight or flee.
• The hypothalamus is involved in the coordination of ANS
responses
– One section of the hypothalamus seems to control
many of the "fight or flight" responses; another
section favors "rest and digest" activities