myers unit three vocab Flashcards
what is a neuron?
a nerve cell; the basic building block of the NS
what is a cell body?
the part of a neuron that contains the nucleus; the cell’s life-support center
what is a dendrite?
the neuron’s branching extensions that receive and integrate messages; conducts impulses toward the cell body
what is a axon?
the neuron extension that passes messages through its branches to other neurons, muscles, or glands
what is the myelin sheath?
fatty tissue encasing the axons of neurons; creates faster transmission speed as neural impulses hop from one node to the next
what are the glial cells?
cells in the nervous system that support, nourish, and protect neurons; play a role in learning, thinking, and memory
what is action potential?
a neural impulse; brief electrical charge that travels down an axon
what is a threshold?
the level of stimulation required to trigger a neural impulse
what is a refractory period?
the brief resting pause that occurs after a neuron has fired; action potentials cannot occur until the axon is returned back to its resting state
all-or-none response
a neuron’s reaction of either firing or not firing
what is a synapse?
between the axon tip of the sending neuron and the dendrite or the cell body of the receiving neuron; called the synaptic gap or synaptic cleft
what are neurotransmitters?
chemical messengers that carry neurons across synaptic gaps; travel across receptor sites on the receiving neuron, influencing whether that neuron will generate a neural impulse
what is reuptake?
a neurotransmitter’s reabsorption by the sending neuron
what are endorphins?
natural, opiate-like neurotransmitters linked to pain control and pleasure
what is a agonist?
a molecule that increases a neurotransmitter’s action
