Neurophysiology II Flashcards
An overview of neuron and action potential
Soma
Cell body of neuron
Dendrites
Branches of neuron specialized to receive signals
Myelin
Fat cells located along axon of neuron
Axon
Extension of neuron through which electrical signals travel
Axon Terminal
Branches of neuron specialized to send signals
Input Zone
Where neurons collect, process, and accumulate information
Integration Zone
Where the decision to produce a neural signal is made
Conduction Zone
Where the electrical signal is transmitted over a great distance
Output Zone
Where the neuron transfers information to another neuron
Action Potential
When the membrane potential of a specific cell rapidly rises and falls
Sodium Ion Channel
Protein through which Na+ passes into the cell
- Concentration of Na+ greater outside of cell than inside
Potassium Ion Channel
Protein through which K+ passes
- Concentration of Ka+ greater inside of cell than outside
Sodium-Potassium Pump
Binds three sodium ions and a molecule of ATP to pass Na+ through
- new shape allows two K+ bind
Resting Membrane Potential
Negative (-65 mv)
Depolarization
Increase in membrane potential
- Only voltage-gated Na+ ion channels open
- Na+ ions rush into cell
Repolarization
Decrease in membrane potential
- K+ ion channels open
- K+ ions leave the cell
- Na+ ion channels close
Hyper-polarized State
Membrane potential is below resting state
- Action potential not possible
Conduction Velocity
The speed of propagation of the action potential
- Dependent on diameter of axon
Saltatory Conduction
Insulated axon is able to conduct electrical signals over great distances
- Electrical current skips along length of axon
- Increased speed
Nodes of Ranvier
Reestablishes ion flow on exposed axon with influxes of sodium ions
- Prevents the electrical charge diminishes over long distances
Multiple Sclerosis
Condition that causes demyelination
- Slower nerve impulses
- Loss of nerve function
Synapse / Synaptic Cleft
Location where a dendritic spine meets an axon terminal
- Release of neurotransmitters
Synaptic Vesicles
Composed of phospholipid bilayer
- Holds neurotransmitters before they are released into the synapse
Receptors
Proteins ( and ion channels) specific to neurotransmitters
- Change shape when bound to neurotransmitters
- Open to allow ions in to neuron
Anterograde Transport
Transport of synaptic vesicles down from the cell body to the axon terminal
Retrograde Transport
Transport of synaptic vesicles up from the axon terminal to the cell body
Microtubule Network
Process by which motor proteins transport synaptic vesicles down the length of the axon
- Requires ATP
Gap Junction
Synapse that can transmit electrical signals (action potential)
- Ion channels on each neuron are directly linked to each other
- Similar to structures in human heart
Refractory Period
Period in which another action potential cannot be fired until the membrane potential returns to resting state
