Nervous System Autonomic Nervous System Reading Chapter 9

Nervous System Autonomic Nervous System Reading: Chapter 9 1

General Functions of the Nervous System 1. Receives sensory input 2. Integrates and processes information 3. Motor output to effectors 2

Organization of the Vertebrate Nervous System Anatomical: CNS (brain + spinal cord) PNS (12 pairs cranial + 31 pairs spinal nerves) Functional: (Chart) 3

Nervous System PNS CNS Integration & Interpretation Sensory Somatic Motor Visceral Somatic (voluntary) Autonomic (involuntary) Sympathetic Parasympathetic 4

Quick Terminology Review Ganglia = cell body OUTSIDE of CNS 5

Motor Control in the PNS Somatic (carcass ONLY) ONLY -1 nerve cell -no ganglia ___Autonomic (viscera mostly) -2 cells (pre- & post-ganglionic) -ganglia (sympathetic chain, collateral & terminal ganglia) -excitatory OR inhibitory -skeletal muscle -smooth & cardiac muscle, glands -specialized neuromuscular jxn. -whole organ is reactive -voluntary -involuntary -fast, myelinated -slow, little myelination -cranial OR spinal -Acetylcholine AND norepinephrine 6 overhead

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Divisions of the Autonomic NS • Divided into Parasympathetic & Sympathetic • Divisions = bilateral (on both sides of body) • Most organs have dual innervation (PS & S) • PS & S systems generally work antagonistically 8

Parasympathetic vs. Rest & Digest Sympathetic Fight or Flight craino-sacral (Cranial III, VII, IX, X, S 2 -4) thoracol-umbar (T 1 to L 2) “long” – “short” – “long” Ach / NE in visceral cavity ONLY in carcass (vasomotor control) & viscera terminal ganglia in/near effector chain & collateral ganglia no mass discharge possible 9

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Autonomic Neurotransmitters -Preganglionic fibers of _sympathetic and parasympathetic__ secrete: acetlycholine and are called: cholinergic _________ -Parasympathetic Postganglionic fibers are cholinergic and secrete: acetylcholine Most sympathetic postganglionic fibers secrete: _norepinephrine (noradrenalin) and are called adrenergic 12

Adrenal Gland Sympathetic NS control • Only 1 cell (no ganglia) • Adrenal gland acts as the post-ganglionic neuron • Adrenal gland secretes epinephrine (85%) & norepinephrine (15%) HORMONES • Hormones: Adrenalin= epinephrine Noradrenalin = Nor epinephrine These hormones intensify the response of sympathetic postganglionic fibers 13

Effect of Sympathetic & Parasympathetic Stimulation on Various Organs Example: Tiger vs. You 14

Some Effects of the Autonomic NS 15

Neural vs. Endocrine Communication Neural -electrical/hardwired -fast -short-term changes -no direct effect on met. -some voluntary actions -reflexes Endocrine -chemical -slow -long-term and/or cyclical changes -affects metabolism -involuntary 16

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