Visceral motor neuron (preganglionic) located in the (intermedio)lateral horn of the spinal cord from T-1 to L-2. Axons travel to ganglionic neuron via 1 of 3 paths: 1. enter the sympathetic chain via the white ramus and terminate there or ascend or descend a few segments before terminating 2. enter via the white ramus and exit via a splanchnic nerve and terminate in a prevertebral (collateral) ganglion Figure 60-2; Guyton & Hall Physiologic Anatomy of the Sympathetic Nervous System 3. Enter via the white ramus and exit via a splanchnic nerve and terminate in the adrenal medulla
Transcript
Visceral motor neuron (preganglionic) located in the (intermedio)lateral horn of the spinal cord from T-1 to L-2.
Axons travel to ganglionic neuron via 1 of 3 paths:
1. enter the sympathetic chain via the white ramus and terminate there or ascend or descend a few segments before terminating
2. enter via the white ramus and exit via a splanchnic nerve and terminate in a prevertebral (collateral) ganglion
Figure 60-2; Guyton & Hall
Physiologic Anatomy of the Sympathetic Nervous System
3. Enter via the white ramus and exit via a splanchnic nerve and terminate in the adrenal medulla
Sympathetic Nervous System
Figure 60-1;Guyton & Hall
Sympathetic Organization
Figure 16.4a
Sympathetic Chain
Collateral Ganglia
Adrenal Gland
Sympathetic Distribution
Figure 60-3;Guyton & Hall
ParasympatheticNervous System
Parasympathetic Organization
Parasympathetic Distribution
Neurotransmitters
Receptors of the Autonomic Nervous System
sympathetic
parasympathetic
preganglionic neuron
postganglionic neuron
nicotinic receptors muscarinic receptors
adrenergic receptors
Pharmacology of the Sympathetic Nervous System
• adrenergic or sympathomimetic drugs act like norepi and epi
• these drugs have an effect which is much more prolonged than that of either norepi or epi– isoproterenol stimulates both beta1 and beta2 receptors
(e.g. increases heart rate)– albuterol stimulates only beta2 receptors (e.g.
bronchodilation)
• some drugs act indirectly by increasing the release of norepi from its storage terminals– amphetamine
Pharmacology of the Sympathetic Nervous System
Example - drugs that block the effect of norepi and epi
• beta blockers– beta1 - metoprolol
Pharmacology of the Parasympathetic Nervous System
• parasympathomimetic drugs– nicotine
• activates nicotinic receptors
• cholinesterase inhibitors– neostigmine
• potentiates the effect of acetylcholine
• antimuscarinic drugs– atropine
• blocks the effect of acetylcholine on effector cells
