neurons Flashcards
dendrites
receive incoming messages
cell body (soma)
contains the nucleus
nucleus
makes the decision to fire or not fire
myelin sheath
fatty tissue that insulates axon, speeding up transition of message
schwann cells
non-neuronal cells in the CNS that form myelin sheath
node of ranvier
space between myelin sheath
axon
longest part of the neuron which the electrical message travels the length of
axon terminal buds
the end point of a neuron that releases neurotransmitters into the synapse, sending the message in to the next neuron
resting potential
when a neuron is not firing and has a negative charge with mostly potassium ions inside and mostly sodium ions outside
polarization
at resting potential when sodium is on the outside and potassium on the inside of a neuron
action potential
nerve impulse, causes the neuron to fire
all or nothing principle
when the nucleus decides to fire it fires down the axon completely or not at all
depolarization
when message begins, sodium ions come in and depolarize (neutralize) section of axon
refractory period
potassium ions are pushed out abs neuron pauses to reload
sodium potassium pump
a protein that has been identified in many cells that maintain the internal concentration of potassium ions higher than in the surrounding medium
