Generally involved in the fight or flight response but is constantly trying to maintain homeostasis within the body.
The sympathetic nervous system uses 2 types of neurons:
-Preganglionic / presynaptic neurons: these release the neurotransmitter acetylcholine at the ganglion
-Postganglionic / postsynaptic neurons: these typically release norepineprhine but can also use acetylcholine and epinephrine
Preganglionic neurons are the shorter of the two and reach out from the spinal cord to a ganglion, where they form synapses with postganglionic neurons. These postganglionic neurons are very long and extend across most of the body.
Examples of sympathetic stimulation:
- Iris (eye muscle): pupil dilation
- Salivary glands: saliva production reduced
- Oral / Nasal Mucosa: mucus production reduced
- Heart: heart rate and force increased
- Lungs: bronchial muscles relaxed
- Stomach: peristalsis reduced
- Small intestine: motility reduced
- Large intestine: motility reduced
- Liver: increased conversion of glycogen to glucose
- Kidneys: decreased urine secretion
- Adrenal medulla: norepinephrine and epinephrine secretion
- Bladder: wall relaxed, sphincter closed
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