Essay - the sympathetic division, the parasympathetic...

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1 The parasympathetic nervous system is compared to the brake of a car because even though it does not stop the body, it does slow the body down, sometimes it just keeps things running smoothly, by enabling the body to conserve and store energy. If you are required to act quickly, the parasympathetic nerves will slow your heart rate down and keep your hearts rhythm regular afterwards. The parasympathetic nervous system is a subdivision of the autonomic nervous system, it operates during relaxing states and conserves energy. The parasympathetic nervous system is the opposite of the sympathetic nervous system which tends to speed things up. The parasympathetic nervous system constricts pupils, stimulates tear glands, and it will strongly stimulate salivation. The parasympathetic system will also slow the heartbeat, constrict bronchial tubes in lungs, activate digestion, and inhibit glucose release by the liver. Parasympathetic fibers exit from the base of the brain and from spinal cord areas near the end. Similar to its counter part
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Unformatted text preview: the sympathetic division, the parasympathetic division also has pre- and post- ganglionic neurons. In the parasympathetic division the ganglion will be closer to the area of innervation, which is unlike the sympathetic ganglion because they form immediately lateral and inferior to the spinal nerve, which makes up the so called "chain ganglion". The parasympathetic nervous system uses only acetylcholine as its neurotransmitter. The acetylcholine acts on two different types of receptors, the muscarinic and nicotinic cholinergic receptors. Most transmissions occur in two stages: When stimulated, the preganglionic nerve releases acetylcholine at the ganglion, which acts on nicotinic receptors of the postganglionic nerve. The postganglionic nerve then releases acetylcholine to stimulate the muscarinic receptors of the target organ. It is the muscarinic receptors that create the parasympathetic nervous systems actions of acting like the brake of a car....
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