Download Notes: Divisions of the Nervous System

Divisions of the Nervous System
Maintains homeostasis by controlling all of
the systems of the body.
Main Divisions
• Central Nervous System
(CNS)
* Brain & Spinal Cord
• Peripheral Nervous System
(PNS)
* Nerves that extend out
from CNS
Central Nervous System
• The Brain = Control
center of nervous
system
• Regions of the Brain:
– Forebrain
– Brain Stem:
• Midbrain
• Hindbrain
The Forebrain
• Cerebrum – involved in
memory, learning, speech,
emotions & controls
complex behaviors
– Divided into “hemispheres”
• Left hemisphere controls
movement on the right side of
the body & vise versa
• Thalamus – sorts sensory
data & motor output
• Hypothalamus – controls
homeostasis
The Brainstem
• Midbrain – relays auditory
& visual data to other
brain centers
• Hindbrain:
– Pons – controls breathing
– Medulla oblongata –
controls breathing,
circulation, swallowing &
digestions
– Cerebellum – coordinates
body movement and
balance
Spinal Cord
• Column of nerve tissue
(interneurons) from
hindbrain through vertebral
column
• Carries signals from the
body to the brain & vise
versa
• Reflex – involuntary response to
a stimulus.
– Stimulus is processed through the
interneuron in the spinal cord – not the
brain!!!
– Ex: Patellar reflex
Peripheral Nervous System (PNS)
• Somatic Division of the Nervous System – motor
neurons that you have control over.
• Voluntary movement – skeletal muscle control
• Autonomic Division of the Nervous System – motor
neurons that you do NOT have control over. (heart rate,
breath rate, etc.)
• This controls all systems of the body
• Smooth muscle (heart etc) control
Autonomic Division
• Sympathetic Division
– stimulates activity of the autonomic
system. “fight –or-flight”
– Adrenaline released, heart beats
faster, breathe faster, muscles tense
• Parasympathetic Division
– decreases activity of the autonomic
system
– Adrenaline cleared out, heart slows,
breathing back to normal, muscles
relax
How It’s all Connected
• Information about a
stimulus is brought in by
the sensory receptors
– PNS – Sensory division
• Information is processed
& interpreted by the
interneurons
– CNS – brain (or spinal cord)
• Action is caused by the
motor neurons in
response to the stimulus
– PNS – Somatic division
Divisions of the Human Nervous System
The Nervous
System
Central Nervous
System
(Interneurons)
Peripheral
Nervous System
Sensory Division
Brain
Spinal Cord
(Sensory
Neurons)
Motor Division
(Motor Neurons)
Autonomic
Nervous System
Somatic Nervous
System
Sympathetic
Division
Parasympathetic
Division
Essential Questions
1. Describe the function of each of the regions of the
brain.
2. Where are the neurons that make up the main two
divisions of the nervous system located?
3. How is the PNS divided?
4. What are the divisions of the autonomic nervous
system