Unit 2: Part 1A: Neurons Flashcards
Dendrite
receptors; receives information; where the neurotransmitters or chemicals land
Soma Cell Body
where the nucleus is located; sums up information to see if neuron is at rest or threshold
Axon Hillock
beginning of axon; if threshold is reached it initiates an electric signal impulse (one way)
Axon
where the electrical signal or action potential occurs; sends the message
Myelin Sheath
coating of fat; protects axon and contains the electrical signal; helps with speed of impulse
Nodes of Ranvier
spaces between myelin sheath; amplifies the signal or gives a boost to electrical signal (speed action potential)
Terminal
end point; helps the neuron communicate as it sends chemical
Neurotransmitters
chemicals sent out from the terminal to communicate with other neurons/dendrites; serotonin, clopamine
Reuptake
process where the terminal vacuums or absorbs chemicals after they are released
Synapse
the space or area where two neurons meet communication occurs between the presynaptic neuron and postsynaptic neuron
Afferent Neurons
sensory receptors to brain; approach the brains
Efferent Neurons
motor from brain; exit the brain
Interneurons
internal functions; between
Excitatory Messages
increase the likelihood of neuron firing
Inhibitery Messages
decrease the likelihood of neuron firing
All-or-None
neurons fire or they don’t
Action potential
once it starts, it cannot stop
Resting Potential
ready to fire; in polarized state (mostly negative)
Threshold is Reached
level of stimulation required to trigger neural impulse
Depolarization (Na+ floods in)
becomes less negative
Repolarization (Na+ floods out)
becomes more negative
Restractory Period
resting phase
Reuptake
excess neurotransmitters are reabsorbed
Neurons Rest
-70mV (resting potential)
Message Received
Sodium Ion gates open up -55mv (threshold is reached); All-or-None response
Potassium and Sodium Meet
creates a charge +30mV; charge bounces down the axon, opening more ion gates
Neuron dip
-90mV; enters retractory period
