Autonomic Nerves: 2 divisions
Sympathetic - thoracolumbar
– exits from thoracic and lumbar regions
Parasympathetic - craniosacral
– exits from cranial and sacral areas
Differences between autonomic and somatic nerves
Autonomic:
- Synapses located in ganglions outside cerebrospinal axis
- Extensive peripheral plexuses
- Postganglionic nerves are not myelinated
- Some level of spontaneous activity without intact innervation
Somatic:
- Innervates all organs/glands except skeletal muscle
- Innervates only skeletal muscle
- Synapses within CNS
- Does not form peripheral plexuses
- myelinated
- Denervation results in paralysis, atrophy
Differences between functions of the parasympathetic and sympathetic nervous system
Parasympathetic:
- Bradycardia - Salivation increased
- Vasodilator predominance
- Blood pressure reduced
Sympathetic:
- Conservation of energy - Urine output increased
- Respiration reduced
- GI motility and secretions increased - Renal blood flow increased
- Expenditure of energy
- Tachycardia
- Vasoconstrictor predominance
- Blood pressure increased
- Renal blood flow decreased
- Salivation reduced
- Urine output decreased
- Respiration increased
- GI motility and secretions reduced
Opposing actions of the parasympathetic and sympathetic nervous system
Opposing actions of the parasympathetic and sympathetic nervous system
Ach
HRHRHRHR
M
NE
Opposing actions of the parasympathetic and sympathetic nervous system
Opposing actions of the parasympathetic and sympathetic nervous system
Ach
GI motility
M
NE
( )-
Opposing actions of the parasympathetic and sympathetic nervous system
Opposing actions of the parasympathetic and sympathetic nervous system
Opposing actions of the parasympathetic and sympathetic nervous system
Opposing actions of the parasympathetic and sympathetic nervous system
Iris dilator muscle: Sympathetic(mydriasis)
Iris sphincter muscle: Parasympathetic
(miosis)
Ciliary muscle: sole parasympathetic innervation controlling accommodation
Ciliary muscle: sole parasympathetic innervation controlling accommodation
Ciliary muscles: Only parasympathetic
innervation
Relaxation of ciliary muscles causes flattening of the lens for near and far vision focus
Changes during short distance accommodation
A) contraction of ciliary muscles (M3)B)approximation of ciliary muscles to lensC)relaxation of suspensory ligament D)increased curvature of anterior surface of lens (i.e., spherical) for near vision focus.
Synergistic actions of the parasympathetic and sympathetic nervous system
Synergistic actions of the parasympathetic and sympathetic nervous system
5 key steps in neurotransmission
- Synthesis
- Storage
- Release
Neurotransmitter:- Recognition
- Metabolism
PRESYNAPTICPRESYNAPTIC POSTSYNAPTICPOSTSYNAPTIC
NT
Re-uptake 1Re-uptake 1
Metabolic RemovalMetabolic Removal
ActionActionS & S
R
ReceptorBinding
ReceptorBinding
E
SITE EFFECT
EFFECTS OF STIMULATING MUSCARINIC RECEPTORS (SLUDE)
BRONCHOSPASM
BRADYCARDIA
VASODILATION
MIOSIS
INCREASED URINATION
INCREASED GI MOTILITY
INCREASED SALIVATION
INCREASED TEARSLACRIMAL GLANDS
SALIVARY GLANDS
GI TRACT
BLADDER
IRIS
AIRWAYS
VASCULATURE
HEART
SWEAT GLANDS INCREASED SWEATNG
1, 2vasoconstrictionTPR
contractile forceheart rate1
2 vasodilation, TPR
EFFECTS OF STIMULATING ADRENERGIC RECEPTORS
SITE EFFECT
EFFECTS OF STIMULATING ADRENERGIC RECEPTORS
BRONCHORELAXATION (2)
TACHYCARDIA (1)
VASODILATION
MYDRIASIS (2)
DECREASED URINATION (2)
DECREASED GI MOTILITY (2)GI TRACT
BLADDER
IRIS
AIRWAYS
VASCULATURE
HEART
(2)VASOCONSTRICTION
(1, 2)
UTERUS RELAXATION (2)
Dual Innervation
Predominant Tone
Exceptions -
Primarily parasympathetic NS
blood vessels(only sympathetic)
Exceptions - blood vessels (sympathetic)
- sweat glands (sympathetic cholinergic)
Predominate Autonomic Tone
Arterioles Sympathetic (adrenergic)Veins Sympathetic (adrenergic)
Heart Parasympathetic (cholinergic)Iris Parasympathetic (cholinergic)Ciliary muscle Parasympathetic (cholinergic)GI tract Parasympathetic (cholinergic)Urinary bladder Parasympathetic (cholinergic)Salivary glands Parasympathetic (cholinergic)
Sweat glands Sympathetic (cholinergic)
Site Predominate Tone