The Autonomic Nervous System Lesson 12 Autonomic N

The Autonomic Nervous System Lesson 12

Autonomic N. S. Homeostasis l Maintenance of steady internal state n Effectors l autonomous l Smooth Muscle, Cardiac Muscle, Glands n Psychoactive drugs l autonomic effects common ~ n

Autonomic Subdivisions Sympathetic l Emergency, flight/fight n Parasympathetic l Conservation / vegetative ~ n

Autonomic N. S. : General Features Preganglionic neuron Ganglion Effector Postganglionic neuron

Autonomic N. S. : General Features Effector ACh n At ganglia l Nicotinic receptors l different than neuromuscular l antagonist: hexamethonium ~

Autonomic N. S. : General Features Effector ACh n Neuroeffector junction l Different NT for each division ~

Pharmacology of Autonomic NS Preganglionic neuron l releases ACh n Different NT at effectors l sympathetic division: NE l parasympathetic division: ACh ~ n

Sympathetic vs. Parasympathetic Sympathetic l ganglia near spinal cord l interconnected active together l long-lasting effects n Parasympathetic l ganglia near effector l discrete active independently l transient effects n Antagonistic regulation ~ n

Parasympathetic Sympathetic Pre- Post- Smooth muscle Glands ACh NE Adrenal Glands

Sympathetic Arousal Syndrome Fight or flight situations l Diffuse sympathetic activation n Adrenal glands l releases NE into blood l maintains sympathetic arousal n Parasympathetic rebound ~ n

Effector Responses Effector Sympathetic Parasympathetic Heart + Respiration + Salivation + (putrid) + (profuse) GI + Sweat glands + no input Iris + (radial) + (sphincter) ~

Autonomic N. S. : Summary n Parasympathetic l l l n Conservation Cholinergic Discrete/short-lasting Sympathetic l l l Emergency Noradrenergic Diffuse/long-lasting ~