14: neurons and synapses

what is sensory input

when ears eyes and nose detect prey

sensory integration

when brain and spinal cord interpret sensory input

motor response

when muscles and glands react

what does the central nervous system have

brain and dorsal spinal cord

what is a neuron

cell consisting of a cell body, an axon and dendrites that form communication networks

neural impulses or signals

movement of charged particles (ions) across membrane

what is the distribution of ions of a neuron at rest

inside carries slightly negative charge relative to the outside

inputs and outputs of a sodium potassium pump

3 Na+ out and 2 K+ in

depolarization

sodium channel gates in membrane open and immediately close and interior of the neuron becomes less negative

myelin sheath

fatty neuroglia wrap around portions of axons

nodes of ranvier

gaps that house high densities of sodium channel

synapse

non-physical junction at which a neuron communicates with another cell

presynaptic neuron function

sends the message

postsynaptic neuron

receives the messages

synaptic cleft

space between the two cells