Autonomic Nervous
System
Eunice Lee
Debora Jeong
Joshua Iannotti
Period 4
Organization of Nervous System
Central Nervous System
1. Brain
 A) Forebrain
 (1) Sensory info (receive/process)
 (2) Thinking, perceiving, producing
 B) Brainstem
 (1) Hindbrain
 Balance
 equilibrium
 (2) Midbrain
 Auditory and visual responses
 Motor functions
2. Spinal Cord
 A) connects brain to peripheral nervous system
Peripheral Nervous System
1. Sensory Nervous System
 A) sends info to CNS
 i.e. when someone pokes your finger
2. Motor Nervous System
 A) sends info from CNS
 i.e. when you want to lift your finger
 B) Autonomic vs. Somatic
 (1) Somatic:
 1. voluntary motor
 2. skeletal muscles
 (2) Autonomic:
 1. involuntary motor
 2. smooth and cardiac muscles
 3. Parasympathetic vs. Sympathetic
Reflex Arc
 Definition: a neural pathway that controls a reflex
 i.e. jolting backward when touching something hot
TWO types of Reflex Arc
 1. Autonomic Reflex
 Affects inner organs (visceral= deep)
 Triggered by visceral afferent signaling
 Sensory neuron -> connecting neuron -> motor neuron
 i.e. peristalsis, sweating
 2. Somatic Reflex
 Affects muscles
 Starts with force acting onto a surface
 i.e. hammer on patella
 Then energy is received and sensory neuron senses force
 Then sends signal to motor neuron which sends a signal to
the brain to jerk the knee
 Autonomic
Somatic
Autonomic: Sympathetic vs
Parasympathetic
Autonomic: Sympathetic vs Parasympathetic
Body Part
Sympathetic
Parasympathetic
Eye
Dilates
Constricts
Heart
Rate increases
Rate decreases
Bladder
Relaxes
Contracts
Salivary Glands
Stops production
Increases production
Lungs
Dilate bronchioles
Constrict bronchioles
Liver
Release glucose
N/A
Adrenal Gland
Secrete epinephrine/
norepinephrine
N/A
Intestines/ Stomach
Decreases activities of
muscles and glands
Increases gland
secretions, motility
Kidney
Vasoconstriction/
decreased urine output
N/A
Genitals
Ejaculation
Erection
Arrector pili Muscle
Contract
Relax
Gallbladder
Relaxes
Contracts
Ultimate Outcome for each
System: Autonomic vs. Somatic
Autonomic:
 Maintaining homeostasis:
 Control glands
 Control smooth and cardiac muscle
Somatic:
 Self-Preservation:
 Control skeletal muscles
Ganglionic Fibers
 Axons sent into nerves
 Synapse with neurons
in ganglia first
 PREGANGLIONIC
FIBERS ARE…
 POSTGANGLIONIC
FIBERS ARE…
Sympathetic System
 Preganglionic fibers
 Postganglionic fibers
- Reach spine and leave spine
(rami)
- Synapse in sympathetic
ganglia
- Shorter
- Extend from sympathetic
ganglia
- Longer
Parasympathetic System
 Preganglionic fibers
 Postganglionic fibers
- Continue from ganglia 
- Carried by vagus nerves
organs
- From brain and spinal chord 
- Shorter
ganglia
- Unmyelinated
- Longer
- Myelinated
Sympathetic Neurotransmitters
 Preganglionic fibers secrete AcH
(Acetylcholine)
 Cholinergic
 Postganglionic fibers secrete NE
(Norepinephrine)
 Andrenergic
Parasympathetic Neurotransmitters
 Preganglionic fibers secrete
AcH
 Postganglionic fibers
secrete AcH and Nitric
Oxide
RECEPTORS
 Nicotine AcH Receptor
- Strong Muscle contractions
- Both sympathetic and
parasympathetic
 Adrenergic Receptors
- Postganglionic neurons
- Just sympathetic
 Muscarinic AcH
Receptors
- Receives AcH
- Weak Muscle contractions
- Just Parasympathetic
Termination of Receptors
 AcHe (Acetylcholinesterase)
breaks down AcH
 NE is removed
 NE has prolonged effect
Bibliography
 https://www.uic.edu/classes/pcol/pcol425/restricted/Guenthne
r/Pharm_PNS_new.pdf
 http://faculty.stcc.edu/AandP/AP/AP2pages/Units14to17/unit1
4/ans.htm
 http://www.ncbi.nlm.nih.gov/pubmed/7906875
 http://www.ems1.com/medical-clinical/articles/893632Receptors-and-the-autonomic-nervous-system/