Nerve Impulses & The Eye

sensational typeface- carries galvanic message from receptor to spine Sensory organisation- carries electric message from receptor to spine grimace Impulses Nerve Impulses aim nerve- carries electrical message from spine to effector crevice nerve- connects sensory(prenominal) and motor nerves. too relays message to the brain. Schwann booths-wrap around the axon of the tenacious nerves, creating a thick layer of thread layer, which insulates the nerve and allows for much straightaway conduction speed. The thick layer of tissue layer has gaps in it surrounded by adjoining Schwann cells; these are called Nodes of Ranvier. Motor nerve- carries electrical message from spine to effector Relay nerve- connects sensory and motor nerves. Also relays message to the brain. Schwann cells-wrap around the axon of the long nerves, creating a thick layer of tissue layer, which insulates the nerve and allows for much faster conduction speed. The thick layer of membra ne has gaps in it between adjacent Schwann cells; these are called Nodes of Ranvier. Voltage-Gated K+ transmit open Voltage-Gated K+ transmit open Voltage-Gated Na+ Channels open Voltage-Gated Na+ Channels open A synapse is the junction between 2 nerves. * 1. The wave of depolarization arrives at the synaptic knob.

The membrane in the presynaptic neuron is depolarised to 50mv (threshold potential) and the voltage-gated Na+ impart open, letting Na+ into the cell. * 2. The membrane is depolarised to +30mV and voltage-gated K+ channels open. The membrane potential falls to 90mV and the cell goe s into its refractory period, where the 3Na+! /2K+-ATPase restored the ion concentrations. * 3. different axons, presynaptic nerves also contain a Voltage-gated Ca2+ channel. As the presynapstic membrane depolarises these channels open and let Ca2+ into the cell. * 4. The Ca2+ causes vesicles in the presynaptic nerve to emigrate and fuse with the presynaptic membrane, where they spill neurotransmitter chemical into the synaptic cleft....If you want to approach a full essay, order it on our website: BestEssayCheap.com

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