Peripheral Nervous System: Efferent Division

Autonomic Nervous System Pathways

Preganglionic Neuron: synapses with the cell body of the postganglionic fiber in a ganglion outside the CNS

Postganglionic Neuron: sends axons that end on the effector organ

Dual Innervation

innervation of an organ by both branches

Sympathetic Nervous System

division of autonomic nervous system

sympathetic postganglionic fibers release norepinephrine and epinephrine, adrenergic fibers

dominate during fight or flight response

Parasympathetic Nervous System

division of autonomic nervous system

parasympathetic postganglionic fibers release acetylcholine, cholinergic fibers

dominate during rest and digest response

Adrenal Medulla

modified part of the sympathetic nervous system

adrenal glands are endocrine glands

secreted catecholamine hormones on stimulation

ANS+CNS relationships

-some autonomic reflexes are integrated at the spinal cord level

-medulla within brain stem is the region most directly responsible for autonomic output

-hypothalamus integrates autonomic, somatic, and endocrine response

-autonomic activity can be influences by prefrontal association cortex

Somatic Nervous System

motor neurons supply skeletal muscle, bring about movement

Neuromuscular Junction

where motor neurons and skeletal muscle fibers are chemically linked

each muscle cell only has one neuromuscular junction

ACh is the neuromuscular junction neurotransmitter

vulnerable to several chemical agents and diseases