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19 Cards in this Set
- Front
- Back
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Sympathetic Division - Exception
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- Innervation of the Adrenal Medulla: Preganglionic neuron to adrenal medulla - Passes thru paravertebral ganglia & synapses directly on adrenal medulla - No postganglionic neuron (neurotransmitter released to Blood Stream)
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Adrenal Medulla: Inner Portion of Adrenal Gland
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- Modified parasympathetic ganglion, no postG neuron
- Produces catecholamines (mostly epinephrine (80%) - Sympathetic drive for systems w/out direct ANS innervation (e.g. skeletal muscles) - Effects last longer on other tissues (e.g. smooth muscle) |
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Parasympathetic Nervous System
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- Cell bodies:
-- In brain: cranial nerves III, VII, IX, X -- In sacral spinal cord - Ganglia: Terminal ganglia in or near effector organ |
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Peripheral Nervous System: Somatic, Autonomic
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- Autonomic: aka visceral motor division
- Sympathetic division - Parasympathetic division |
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Somatic Nervous System
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- Axons of motor neurons: Cell bodies in ventral horn of spinal cord
- Innervate skeletal muscle: only stimulate, unlike ANS - Inhibition takes place in CNS only |
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Actions of ANS: Regulates visceral activities (homeostasis) - visceral motor system
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- Glands, cardiac and smooth muscle: all effectors other than skeletal muscle
- Both divisions are usually partially active - Tonic Activity: Autonomic Tone |
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Sympathetic Nervous System: Fight or Flight (Emergency Response)
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- Usually Global, Provides energy & fuel, Prepare for physical exertion,
- Increases: Sweating, Heart rate, Blood pressure, Blood glucose levels - Decreases: Digestion, Urination |
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Parasympathetic Nervous System: Rest and Relax System
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- Rest and Digest
- Usually acts Locally - Increases: Digestion, Urination - Constricts Pupils - Decreases heart rate |
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Dual Autonomic Innervation: Most organs have both
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- Sympathetic and Parasympathetic usually oppose each other: Conservation of energy, faster responses
- Exceptions: Sympathetic only, Parasympathetic only, Cooperative Dual - Symp: Adrenergic, Parasymp: Cholinergic |
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Dual Autonomic Innervation: Exceptions - Sympathetic Only
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- Adrenal Medulla: Stimulates secretion of epinephrine
- Sweat Glands: Stimulates secretion - Most blood vessels: Stimulates vasoconstriction |
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Dual Autonomic Innervation: Exceptions - Parasympathetic Only
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- Lacrimal Glands
- Nasal Glands |
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Dual Autonomic Innervation: Exceptions - Cooperative
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- Two divisions act on effectors to produce a unified overall effect
-- Salivation |
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Anatomy of ANS: (Both Para & Sympathetic)
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- Two neuron chain. - Preganglionic fiber: myelinated, CNS to Autonomic ganglion, soma in brain to lateral horn of spinal cord. - Postganglionic fiber: unmyelinated, Autonomic ganglion to effector organ, soma outside CNS, ends in swellings (vericosities)
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Somatic vs. Autonomic Pathways
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- Somatic: one cell from CNS to Effectors (Muscles)
- ANS: Two cells, - ANS: Ach (PSNS) or NE (SNS) at second synapse - Both ACh at first synapse |
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Sympathetic Nervous System
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- Cell bodies: Preganglionic
- Lateral horn - Thoracic & Lumbar levels - Ganglia: Sympathetic chain ganglion |
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Sympathetic Division Pathways:
1. Synapse with Postganglionic Neuron at Same Level |
- Leave spinal cord thru ventral root to Spinal Nerve
- SN to chain ganglia via white ramus communicans - Synapse w/ post-GN at same level - Reenter SN via shunt called gray ramus communicans - On to the effector |
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Sympathetic Division Pathways:
2. Synapse with Postganglionic Neuron at Different Level |
- Enter Sympathetic Chain Ganglia via white ramus communicans at same spinal level
- Synapse with post-GN at different level - Leave via gray ramus communicans at different level - On to effector |
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Sympathetic Division Pathways:
3. Splanchnic Nerves Do Not Synapse in the Chain Ganglia |
- Most synapse in collateral ganglia
- Not segmentally arranged |
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Parasympathetic Division: Anatomy - Cranial Nerve X
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- Vagus "Wandering" nerve: 90% of all parasympathetic fibers
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