vocab terms unit 2 Flashcards
memorize vocab terms from unit 2
neuron
a nerve cell; the basic building block of the nervous system
dendrites
a neuron’s often bushy, branching, extensions that receive and integrate messages, conducting impulses toward the cell body
cell body/soma
the part of a neuron that contains the nucleus; the cell’s life support center
axon
the neuron extension that passes messages through its branches to other neurons or to muscles or glands
myelin sheath
a fatty tissue layer segmentally encasing the axons of some neurons; enables vastly greater transmission speed as neural impulses hop from one node to the next
terminal buttons/ axon terminals
the long, thin, hollow extension of a neuron that normally carries a nerve impulse away from the cell body
neurotransmitters
chemical mesengers that cross the synaptic gap between neurons, when released travel and bind to receptor sites
synapse
the junction between teh axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
receptor sites
a region of specialized membrane on the surface of a cell that contains receptor molecules that receive and react with particular messenger molecules
threshold
the level of stimulation required to trigger a neural impluse
action potential
a neural impulse; a brief electrical charge that travels down an axon
all-or-none principle
a neuron’s of either firing with afull -strngth response or not firing
neural firing
allows a nerve cell to transmit an electrical signal down the axon toward other cells
excitatory neurotransmitters
allow greater chance of action potential
inhibitory neurotransmitters
cause smaller chance of action potential
