Chapter 17: The Autonomic Nervous System

Ganglionic neurons

Near (terminal) the target organ or within (intramural) the target organ

Preganglionic neurons

Nerve fibers that supply a ganglion. Originate within the brain stem and spinal cord. Do not diverge as much as the sympathetic division Parasympathetic division is more localized and specific as compared to the sympathetic division

What are the three major components of the sympathetic nervous system?

Preganglionic neurons between T1 and L2 Neuronal cell bodies in ganglia near the vertebral column Specialized neurons in the interior of the suprarenal gland

List two general statements about the synapses and neurotransmitters in the ANS.

Sympathetic releases norepinephrine and acetylcholine while the parasympathetic only releases acetylcholine

What are the two subdivisions of the ANS?

Sympathetic- (thoracolumbar) are short and extend from the spinal cord to the sympathetic chain. Thoracic and upper lumbar nerves synapse in ganglia near the spinal cord Parasympathetic - (craniosacral division) are long and extend from the spinal cord to the body organs. Synapses are located near the target organ

Compare and contrast the SNS and the ANS.

The sympathetic nervous system promotes the "fight or flight" reflex. It prepares the body to be able to handle potentially threatening situations as deemed by the CNS in response to stimuli. The parasympathetic nervous system counteracts the actions of the sympathetic nervous system once the event has passed.