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Autonomic Nervous System Review Anatomy Visceral Efferent of Peripheral Nervous System Effectors are smooth muscle, cardiac muscle, glands Below conscious level Sympathetic Nervous System Expends energy Preganglionic neurons arise T1-L2 Adrenal medulla Sympathetic Division • Preganglionic cell bodies in lateral horns of spinal cord T1-L2 • Preganglionic axons pass through ventral roots to white rami communicantes to sympathetic chain ganglia – Four routes possible • • • • Spinal nerves Sympathetic nerves Splanchnic nerves Innervation to adrenal gland 16-4 Parasympathetic Nervous System Conserves energy Preganglionic neurons arise S2-S4 and Cranial Nerves III, VII, IX, X Does not typically innervate skin or blood vessels Parasympathetic Division • Preganglionic cell bodies in nuclei of brainstem or lateral parts of spinal cord gray matter from S2-S4 – Preganglionic axons from brain pass to ganglia through cranial nerves – Preganglionic axons from sacral region pass through pelvic nerves to ganglia • Preganglionic axons pass to terminal ganglia within wall of or near organ innervated 16-6 Neurotransmitters Acetylcholine (Cholinergic) – Preganglionic fibers of PNS & SNS – Postganglionic fibers of PNS Norepinephrine (Adrenergic) – Postganglionic fibers of SNS Actions Fight or flight Rest & relaxation Controls Hypothalamus