Autonomic Nervous System Flashcards
What is the autonomic nervous system?
A mostly involuntary component of the nervous system
Located in the CNS and the PNS
Has two parts, SNS and PSNS which act in conjunction
Which provides Fine, discrete, fast control of body homeostasis
Has afferent, connector and efferent neurons
What is the sympathetic nervous system?
Part of the ANS
Which prepares the body for the flight or fight response
When challenged with an internal or external stressor
Preganglionic Thoracolumbar outflow T1 to L2
Forming the paravertebral sympathetic chain
Gangliotransmitter is ACh
Tachycardia Peripheral to central Blood redistribution Hypertension Mydriasis Bronchodilator Decrease visceral motility Sphincter contraction Sweating Goosebumps
What is the parasympathetic system?
Part of the ANS
controls the resting phase of the body
Craniosacral outflow III - Edinger westphal nucleus VII - superior salivary and lacrimal nuclei IX - inferior salivary nucleus X - dorsal vagal nucleus S2 S4
Gangliotransmitter is ACh
Bradycardia Visceral blood flow Hypotension Miosis Bronchoconstriction Peristalsis Sphincter relaxation NO EFFECT ON SWEAT GLANDS
What are the important ganglia and plexuses of the ANS?
SNS
Paravertebral ganglia
PSNS
Ciliary - eye
Pterygopalatine - lacrimal
Submandibular - SM and SL salivary
Otic - parotid
Cardiac, pulmonary, esophageal, coeliac, superior mesenteric, inferior mesenteric, aortic , myenteric and mucosal plexuses
Hypogastric plexuses
What is the neurophysiology of ANS?
Gangliotransmitter is ACh
Receptor is Nicotinic (fast EPSP)
Nicotine, Hexamethonium, tetraethyl ammonium compete for ACh and act as ganglion blockers
PSNS
Postganglionic neuron cholinergic releases ACh which bind to Muscarinic receptor on effectors
SNS
Postganglionic neuron adrenergic Norepinephrine to effectors
ACh to sweat glands and vessels
Epinephrine from adrenal medulla
Important points on ANS innervation?
SNS reduce exocrine gland secretions Diaphoresis Coronary vasodilation - beta 1 Coronary vasoconstriction - alpha Bronchodilator Bronchial arterioconstriction Glycogenolysis Reduce GFR Ejaculation
PSNS No effect on sweat glands No effect on blood vessels Bronchoconstriction Bronchial hypersecretion Bronchial arteriodilation UOP and BO Erection
What are the important ANS defects?
Surgical IIIrd nerve palsy Light near dissociation VII nerve PSNS loss of tearing Frey syndrome (sweat and tears for food) Horner syndrome Diabetes - anhydrosis, postural hypotension Hirschprung disease
NEUROGENIC BLADDERS Automatic bladder (urge incontinence) Detrusor Sphincter Dyssynergia Autonomous sensory (overflow incontinence) Autonomous motor (retention)
Spinal cord injury loss of
Bladder
Bowel
Erection and ejaculation
