Peripheral Nervous System Flashcards
Autonomic Nervous System
controls visceral organ activity
Two Neuron System
Preganglionic neuron (fiber) Postganglionic neuron (fiber)
Preganglionic neuron (fiber)
Cell body
located in CNS
Postganglionic neuron (fiber)
Cell body
located in ganglia – innervates target organ
Two Branch System
Sympathetic
Parasympathetic
Sympathetic system
fight or flight
Parasympathetic
rest and digest
Sympathetic Branches
Thoracic and lumbar origins, Short Preganglionic neuron,
Long Postganglionic neuron
Generally excitatory
Parasympathetic Branches
Cranial and sacral origins – Long Preganglionic neuron • Ganglia in or near target organ – Short postganglionic neuron – Generally inhibitory
Where are neurotransmitters released?
from varicosities
– Do NOT target a single cell
Acetylcholine
Ganglion of both branches
Epinephrine/Norepinephrine
sympathetic
postganglionic
Acetylcholine
parasympathetic
postganglionic
Cholinergic receptors
Nicotinic
Muscarinic
Where are Nicotinic receptors found
ANS ganglia, Motor End Plates, Non-Specific Cation channels
Where are Muscarinic receptors found
Target Tissues and G Protein coupled receptors
Adrenergic receptors
Alpha (α) adrenergic
Beta (β) adrenergic
α1
Ca2+ second messenger
– Generally stimulatory
α2
nhibits adenylate cyclase
– Generally inhibitory
β 1
Cardiac – stimulatory
β 2
Generally inhibitory
Agonists
mimic
Antagonists
block
Neuromuscular Junction
Motor neurons innervate skeletal muscle. Motor unit. Terminal Button. Motor end plate
Neurotransmitter
Acetylcholine. Ca2+ dependent release.
End-Plate Potential
Similar to a EPSP – but larger
