Download Autonomic Nervous System

Autonomic Nervous System
Review
Anatomy

Visceral Efferent of Peripheral Nervous
System
 Effectors are smooth muscle, cardiac
muscle, glands
 Below conscious level
Sympathetic Nervous System

Expends energy
 Preganglionic neurons arise T1-L2
 Adrenal medulla
Sympathetic Division
• Preganglionic cell bodies in
lateral horns of spinal cord
T1-L2
• Preganglionic axons pass
through ventral roots to
white rami communicantes
to sympathetic chain ganglia
– Four routes possible
•
•
•
•
Spinal nerves
Sympathetic nerves
Splanchnic nerves
Innervation to adrenal
gland
16-4
Parasympathetic Nervous
System

Conserves energy
 Preganglionic neurons arise S2-S4 and
Cranial Nerves III, VII, IX, X
 Does not typically innervate skin or blood
vessels
Parasympathetic Division
• Preganglionic cell bodies
in nuclei of brainstem or
lateral parts of spinal cord
gray matter from S2-S4
– Preganglionic axons from
brain pass to ganglia
through cranial nerves
– Preganglionic axons from
sacral region pass through
pelvic nerves to ganglia
• Preganglionic axons pass
to terminal ganglia within
wall of or near organ
innervated
16-6
Neurotransmitters

Acetylcholine (Cholinergic)
– Preganglionic fibers of PNS & SNS
– Postganglionic fibers of PNS

Norepinephrine (Adrenergic)
– Postganglionic fibers of SNS
Actions

Fight or flight
 Rest & relaxation
Controls

Hypothalamus