Nerve Impulses & The Eye

receptive(prenominal) typeface- carries galvanic message from receptor to spine Sensory facial expression- carries electric message from receptor to spine spirit Impulses Nerve Impulses push nerve- carries electrical message from spine to effector pinch nerve- connects sensory and motor nerves. too relays message to the brain. Schwann stalls-wrap around the axone of the massive nerves, creating a thick layer of create from raw material layer, which insulates the nerve and allows for much faster conduction speed. The thick layer of tissue layer has gaps in it between 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 memb rane 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 cardinal 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 refr actory period, where the 3Na+/2K+-ATPase res! tored 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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