Unit 2 vocab Flashcards
neuron
a nerve cell; the basic building block of the nervous system
cell body
the part of a neuron that contains the nucleus; the cells life support center
dendrites
a neurons often bushy branching extensions that receive and integrate messages conducting impulses toward the cell body
myelin sheaths
a fatty tissue layer segment ally encasing the axons of some neurons ; enables vastly greater transmission speed as neural impulses hop from one node to the next
axon
the neuron extension that passes messages through its branches to other neurons or to muscles or glands
glial cells
cells in the nervous system that support nourish and protect neurons; they also play a role in thinking and memory
action potential
a neural impulse; a brief electrical charge that travels down an axon
threshold
the level of stimulation required to trigger a neural impulse
refractory period
in neural processing, a brief resting pause that occurs after a neuron has fired: subsequent action potentials cannot occur until the axon returns to its resting state
all or none response
a neurons reaction of either firing (WITH A FULL STRENGTH RESPONSE) or not firing
synapse
the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. The tiny gap at the junction is called synaptic gap or synaptic cleft
neurotransmitters
chemical messengers that cross the synaptic gaps between neurons. When released by the sending neuron, neurotransmitters travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing whether that neuron will generate a neural impulse
reuptake
a neurotransmitters re-absorption by the sending neuron
endorphins
“morphine within” - natural opiate-like neurotransmitters linked to pain control and pleasure
agonist
a molecule that increases a neurotransmitters action
