Unit 3 Flashcards
Dendrites
receive information and put it toward the cell body
Axons
transmit signals away from the cell body, usually longer and have fewer branched extensions
Axon hillock
where signals that are coming into the cell body are tallied
Action potential
nerve impulse - brief electrical signal that is sent down the axon
Axon terminal
lies close to an adjacent cell, almost touching but not quite
Chemical synapse
communication pathway
Synaptic cleft
the space between two cells where the communication pathway lies
Presynaptic cell
the cell giving out the neurotrnasmitters
Postsynaptic cell
the cell receiving the neurotransmitters
Neurotransmitter
chemical messenger
Receptors
Channels that let in ions, but instead of responding to changes in voltage, they are binding to neurotransmitters - ligand-gated channel
Glial cell
support cell for neurons
Astrocyte
specialized glial cell, helps maintain the blood/brain barrier
Schwann cells
insulate motor and sensory neurons
Oligodendrocytes
insulate brain and spinal cord
Myelin sheath
Schwann cells and oligodendrocytes
Nerve signal
a change in the voltage across the plasma membrane of a neuron
Voltage
change in the electrical signal between two points
Ion
charged molecule or simple element
Membrane potential
the charge that is held across the plasma membrane of a cell
Refractory period
the time it takes the cell to reset to fire again
Action Potential
a rapid change in the voltage across a cell membrane that occurs when a cell is activated by a stimulus
Speed is affected by
diameter of axons and myelination
Nodes of Ranvier
axon spaces between adjacent myelin internodes