Download Autonomic Nervous System: Synapses, Neurotransmitters, and Effects and more Slides Physiology in PDF only on Docsity! Autonomic Nervous System
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Terms • Synapse – junction between 2 neurons that communicates the message from the presynaptic neuron to the postsynaptic neuron • Ganglion (pl. ganglia) – a cluster of neuronal cell bodies in the PNS • Preganglionic neuron – cell body lies within the CNS - its axon, the preganglionic fiber synapses with the 2nd motor neuron, the ganglionic neuron, in a peripheral autonomic ganglion • Postganglionic fiber (axon) of the ganglionic neuron extends to the visceral organs Docsity.com Neurotransmitters • Cholinergic fibers release the neurotransmitter ACh – All ANS preganglionic axons – All parasympathetic postganglionic axons • Adrenergic fibers release the neurotransmitter NE – Most sympathetic postganglionic axons – Exceptions: sympathetic postganglionic fibers secrete ACh at sweat glands and some blood vessels in skeletal muscles Docsity.com Parasympathetic and Sympathetic Nervous System: • A subdivision of the PNS • Not under conscious control • Controlled by medulla oblongata and hypothalamus • PNS supplies stimulation via motor nerves to smooth and cardiac muscle and to glands Docsity.com Biofeedback: • Conscious control of ANS • Ex. Yoga, meditation • Monitoring devices useful for: - epilepsy - digestive problems - chronic headaches - high blood pressure - generalized stress - anxiety - insomnia Docsity.com Fight or flight adaptive effects include: • increased cardiac activity, increased blood pressure, dilation of skeletal muscle blood vessels • constriction of blood vessels in skin • dilation of pupil • inhibition of gut and urinary bladder contractions • increase in blood glucose and free fatty acid levels • dilation of bronchial smooth muscle • secretion of viscous saliva • sweating • lower threshold for reticular formation activation • liver produces glucose to provide energy for muscle contraction. Docsity.com neurotransmitter is acetylcholine D = digestion, defecation, diuresis (urinating) Parasympathetic activation results in: • decreased cardiac activity • secretion of watery saliva and stimulation of GI secretions • contraction of urinary bladder • increased insulin and glucagon secretion • bronchiole constriction Docsity.com Sites of synapses between pre and postsympathetic ganglia • sympathetic trunk ganglia - located from base of skull to coccyx • prevertebral ganglia - innervates organs below the diaphragm Docsity.com
