Organization
of the
Nervous
System
Chapter 12
Closer look at the CNS
• Processes, integrates & stores
information; determines
emotions
• Connected to all other parts of
the body by the PNS
2 subdivisions of PNS:
• Sensory (afferent)
division
Brings info from
receptors to CNS
•
Motor (efferent)
division
Carries commands
from the CNS to
muscles & glands
2 parts of the Motor division:
• Somatic Nervous System
(SNS)
Voluntary action
Output to skeletal muscles
•
Autonomic Nervous System
(ANS)
Involuntary action
Output to smooth or cardiac
muscle or glands
2 divisions of ANS:
• Sympathetic Division – for emergencies of “fight or
flight”
Mobilizes the body for action, arousal, alertness
Increases heart rate & breathing, pupils dilate, blood
pressure ↑
Main players: hormones epinephrine and
norepinephrine produced by adrenal gland
• Parasympathetic Division – for metabolic/ physiologic
“business as usual” or “rest and repose”
Slows the body down to keep its rhythm
Enables the body to conserve and store energy