KAAP309 Chapter Notes - Chapter 15: Gray Ramus Communicans, Pelvic Splanchnic Nerves, Lumbar Splanchnic Nerves
21 Mar 2017
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Motor neuron cell bodies are in the cns. Axons extend in spinal or cranial nerves to the skeletal muscles they activate. Lacks ganglia: dorsal root ganglia are part of the sensory division of pns. Cell body of preganglionic neuron 1st neuron in chain resides in brain or spinal cord: preganglionic axon synapses with 2nd motor neuron. Postganglionic neuron 2nd motor neuron in chain: cell body: autonomic ganglion resides outside the cns, postganglionic axon extends to the effector organ. Preganglionic axons: thin, lightly myelinated, many are incorporated into spinal or cranial nerves. Postganglionic axons: thinner, non-myelinated, many are incorporated into spinal or cranial nerves. Release acetylcholine (ach) at synapses with skeletal muscle fibers. Effect: determined by type of receptors on target organ. Higher brain centers regulate & coordinate both motor activities. Most spinal nerves contain both somatic & autonomic fibers. Most adaptations to internal/external stimuli: skeletal muscles + visceral organs. Ex: skeletal muscles are working hard increased need for o2 and.
