- During REM sleep, the EEG resembles that of a person who is awake.
- Most dreams occur during REM sleep.
CNS Effector Organ
Preganglionic / Postganglionic / O Sympathetic •-—--—-.M
ACh J t Muscarinic ^-Nicotinic receptor receptor
ACh-^i Adrenal gland
ACh-7 ^Nicotinic receptor
* Except sweat glands, which use ACh.
Figure 2-1. Organization of the autonomic nervous system. ACh = acetylcholine; CNS = central nervous system.
a. Parasympathetic ganglia are located in or near the effector organs.
b. Sympathetic ganglia are located in the paravertebral chain.
2. Preganglionic neurons have their cell bodies in the CNS and synapse in autonomic ganglia.
- Preganglionic neurons of the sympathetic nervous system originate in spinal cord segments Ti-L3, or the thoracolumbar region.
- Preganglionic neurons of the parasympathetic nervous system originate in the nuclei of cranial nerves and in spinal cord segments S2-S4, or the craniosacral region.
3. Postganglionic neurons of both divisions have their cell bodies in the autonomic ganglia and synapse on effector organs (e.g., heart, blood vessels, sweat glands).
4. Adrenal medulla is a specialized ganglion of the sympathetic nervous system.
- Preganglionic fibers synapse directly on chromaffin cells in the adrenal medulla.
-The chromaffin cells secrete epinephrine (80%) and norepinephrine (20%) into the circulation (see Figure 2-1).
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