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Anatomy (Subject) / Anatomy IV (Lesson)
- Functions of the ANS - part of the PNS controlled by the hypothalamus - unvoluntarily - in control of cardiac muscle tissue, smooth muscle tissue and glands
- Parts of the ANS (2) 1. Sympathetic - follows stressful stimuli - increased heart rate, sweating, dilated pupils,... 2. Parasympathetic - increased gut motility, decreased heart rate
- Sensory neurons (afferent) - cell bodies located in ganglia just like in the SNS
- Motor neurons (efferent) - cell bodies aren't in the grey matter of the brain and spinal cord like with those of the SNS but outside of the grey matter: 1. Preganglionic/presynaptic neuron in the grey matter of the CNS, myelinated 2. Postganglionic/postsynaptic neuron outside of the grey matter, unmyelinated
- Parasympathetic/Sympathetic anatomy (preganglionic) 1. Parasympathetic - Preganglionic cell bodies are located in grey matter --> cranio-cranial nerves (III, VII, IX, X) and sacral nerves (S2-S4) - supply of organs of the head and trunk 2. Sympathetic - Preganglionic cell bodies located in grey matter --> between T1-L2 sacral nerves - supply of organs of the head and trunk, limbs and body wall
- Parasympathetic ganglia - synapses between preganglionic and postganglionic neurons --> locations close to the organ they will supply
- Sympathetic ganglia - synapses between preganglionic and postganglionic sympathetic neurons - each spinal nerve has a sympathetic input which enables the sympathetic nerves to reach the limbs and body wall --> distribution of prevertebral ganglia (supply abdominal organs), paravertebral ganglia/trunk on either side of the vertebral column
- Sympathetic ganglia types (3) 1. Synapse with postganglionic neuron in the paravertebral ganglion at the same level 2. Ascend/descend in the paravertebral chain to synapse in a ganglion ata different level 3. Pass through the paravertebral ganglion/region without synapsing
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