The Autonomic Nervous System Lesson 12

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

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

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

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

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

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

Sympathetic vs. Parasympathetic n 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 ~

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

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

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

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