Recall...
Two major divisions
The Peripheral Nervous System
Section 8.3
Peripheral Nervous System
 the part of the nervous system outside the CNS
 connects the CNS to the limbs and organs
Divisions of the PNS
Peripheral Nervous System
 takes in information about external and internal
environments
Somatic System
Autonomic System
under voluntary control
under involuntary control
Sympathetic
Division
Parasympathetic
Division
“fight-or-flight”
“rest and digest”
Somatic System
Autonomic System
 aka “motor system”
 generally under involuntary control
 under voluntary control
 exceptional cases: reflexive
responses
 hypothalamus & medulla
 controls smooth muscle, cardiac muscle, glands
 cerebral cortex
 maintains homeostasis
 neurons that carry
signals to skeletal
muscles
motor cortex
 further division:
 sympathetic
 parasympathetic
The Autonomic Nervous System:
Sympathetic and Parasympathetic Divisions
Sympathetic Division
“Fight or Flight”
 activated in stress situations
 largely opposite in their functions
 main NTs: norepinephrine, epinephrine
 work together (complementarily) to maintain balance
 examples of response:
 pupil dilation
 dilation of airways
 increased heart rate
sympathetic =
"fight or flight"
response
 inhibited digestion
parasympathetic
= “rest and digest"
 release of glucose from glycogen
Fight or Flight:
Body’s reaction to a
harmful or
threatening situation
Case study: Amphetamines
Parasympathetic Division
“Rest and Digest”
 amphetamines - class of stimulant drugs, including
amphetamine and its derivatives
 opposite reactions from sympathetic
 Adderall, methamphetamine, MDMA (ecstasy, molly)
 promotes calming and return to self maintenance
 causes excessive release of norepinephrine in the
 main NT: acetylcholine
sympathetic system
 increased alertness, dilated pupils, increased heart rate,
dry mouth, decreased hunger
 additional effects on dopamine and
serotonin release/re-uptake
Rest and Digest:
Body’s mechanisms
to restore and
conserve energy
Summary
Homework
 The peripheral nervous system is further divided into
 Pg. 373 #1, 2, 4-5, 8-9,11
two branches:
 Somatic – Under voluntary control
 Autonomic – Under involuntary control
 Sympathetic – Activated in stressful situations
 Parasympathetic – Activated when body is calm and at rest