| Flap 1 |
Flap 2 |
| Does degradation or decrement occur during the action potential? |
No |
| Is there a change in shape of wave form during the action potential? |
No |
| True or false, the action potential is an all or none response? |
True |
| True or false, the action potential is a self reinforcing signal? |
True |
| Action Potential propagation is dependent upon:? |
Properties of the voltage gated channel and Cable properties of the cell |
| What are cable properties of the cell? |
1. Resistance (ie. Cell membrane, Ion concentrations, and Cell Diameter) 2. Capacitance |
| What is the threshold determined by? |
The protein structure of the voltage gated channel |
| How many ions move per a protein cycle? |
5-6 ions |
| True or False, the action potential at one location can act as a stimulus for production of an action potential at an adjacent region of the membrane? |
True |
| What is the generation of a new action potential at each site referred to as? |
Self Reinforcing Signal |
| True or false, Nerve and muscle cells have the properties of an electrical cable? |
True |
| In nerve and muscle cells the plasma membrane act as what? |
Insulation |
| In nerve and muscle cells the cytoplasm act as what? |
A core conductor |
| True or false, the cytosolic resistance is greater than the membrane resistance? |
False, Rm is greater than Rc |
| True or False, Membane resistance has a direct relationship to membrane permeablity? |
False, Rm is inveersely related to membrane permeablity |
| Why do ions have difficulty penetrating the membrane? |
Because the membrane is nonpolar |
| What is Ri or Rc? |
Cytoplasmic Resistance - the resitance of ions to flow in the cytoplasm |
| What determines the velocity of propagation? |
Space and Time constants |
| Velocity equals? |
Space Constant / Time Constant |
| Define the space constant? |
It is a measure of the distance it takes for the initial depolarization voltage to decline by 1/e or about 63%. |
| Define the Time Constant? |
It is a measure of the time it takes for the initial action potential voltage to decline by 1/e or about 63%. |
| True or false, If the space constant is large - the potential will spread a greater distance along the axon and bring distant regions to threshold sooner? |
True |
| True or False, If a time constant is large - the action potential will be initiated sooner and velocity of the propagation is faster? |
False, Small time = faster |
| True or False, it is desireable to have axons with high propagation velocities? |
True |
| How does compression of a nerve effect its ability to conduct a nerve impulse? |
Compression alters the velocity of conduction by decreasing the cell diameter and in turn decreases the space constant, thus decreasing the propagation velocities |
| What causes saltatory conduction? |
Schwann cells |
| What is saltatory conduction? |
The conduction of the action potential that jumps from node to node that allows the impulse to travel at great speeds |
| How does Saltatory conduction effect the Velocity of Conduction. |
Remember, Velocity is dependent upon the Space Constant and the Time Constant. So the space constant is increased and the Time constant is decreased. |
