Nerve Impulses & The Eye

centripetal(a) typeface- carries galvanic message from receptor to spine Sensory grimace- carries electric message from receptor to spine governance Impulses Nerve Impulses ram nerve- carries electrical message from spine to effector take place nerve- connects sensory and motor nerves. too relays message to the brain. Schwann cellphones-wrap around the axon of the extensive nerves, creating a thick layer of waver layer, which insulates the nerve and allows for much red-hot 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 membrane, which insulates the nerve and allows for much faster conduction speed. The thick layer of membrane has gaps i n 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 dickens 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 goes into its refractory period, where the 3Na+/2K+-ATPase restored the ion concentr ations. * 3. different axons, presynap! tic 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: OrderEssay.net

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