Sympathetic vs. Parasympathetic Nerves
12th Grade · Science · 45 min
Lesson Preview
Learning Objective
I can differentiate between the structures and functions of the sympathetic and parasympathetic nervous systems.
- 1
The sympathetic nervous system, also known as the "fight or flight" system, prepares the body for stress, while the parasympathetic nervous system, or "rest and digest" system, conserves energy and promotes relaxation.
- 2
In the sympathetic nervous system, preganglionic neurons originate in the thoracic and lumbar regions of the spinal cord, whereas in the parasympathetic nervous system, preganglionic neurons originate in the brainstem and sacral spinal cord.
- 3
The neurotransmitter acetylcholine is used at preganglionic synapses in both the sympathetic and parasympathetic nervous systems; however, the sympathetic nervous system uses norepinephrine at its postganglionic synapses, while the parasympathetic nervous system uses acetylcholine at both pre- and postganglionic synapses.