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# Nerve Transmission This document describes the transmission of nerve impulses. ## Analogies The analogy of straws is used to illustrate different levels of nerve organization: * **Individual plastic straw:** axon * **Paper wrapper:** endoneurium * **Bundle:** fascicle * **Plastic wrap:...

# Nerve Transmission This document describes the transmission of nerve impulses. ## Analogies The analogy of straws is used to illustrate different levels of nerve organization: * **Individual plastic straw:** axon * **Paper wrapper:** endoneurium * **Bundle:** fascicle * **Plastic wrap:** perineurium * **Bundles of straws:** nerve * **Box:** epineurium ## Order of Nerve Impulse Transmission The following events of nerve impulse transmission are ordered: | Step | Event | |---|---| | 1 | Soma generates action potential | | 2 | Action potential arrives at axon hillock | | 3 | Action potential moves along axon | | 4 | Action potential arrives in axon terminal | | 5 | Calcium enters axon terminal | | 6 | Synaptic vesicles stimulated by calcium | | 7 | Neurotransmitters released from synaptic vesicles| | 8 | Neurotransmitter diffuses across synaptic cleft | | 9 | Neurotransmitter binds to receptors on dendrite | | 10| Postsynaptic excitation occurs | ## Additional Information * **Action potential:** A rapid change in the electrical potential of a neuron or other excitable cell, initiated by the stimulus. * **Nodes of Ranvier:** Gaps in the myelin sheath along the axon of a nerve fiber * **Axon:** A long, slender projection of a nerve cell, also called a nerve fiber that transmits impulses away from the neuron cell body. * **Synaptic vesicles:** membrane-bound sacs in axon terminals that store neurotransmitters and release them into the synaptic cleft. * **Neurotransmitters:** Molecules that transmit a signal across a synapse. * **Synaptic cleft:** The gap between two nerve cells across which a neurotransmitter diffuses to transmit a signal.