Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
17 Cards in this Set
- Front
- Back
|
What type of cells are able to conduct electrical signals?
|
Excitable cells
|
|
|
(T or F) AP's are propagated with no change in amplitude
|
True
|
|
|
(T or F) Electrical signals are conducted and decay in amplitude with distance. Due to _________________.
|
T; the 'leak' across the membrane
|
|
|
What are the two processes that control action potential propagation?
|
Active and passive processes
|
|
|
Define the "active process"
|
Voltage dependent opening of Na+ channels
|
|
|
Define the "passive process"
|
involves the flow of ions down their electrical gradient along the axon (this process is responsible to depolarizing inactive regions of the axon)
|
|
|
What must occur for an action potential to be regenerated?
|
When passive flow of ions depolarize Na+ channels in a previously inactive region
|
|
|
What is the limiting process of conduction velocity?
|
Passive flow of ions that activates inactive regions (regeneration)
|
|
|
What are the resistances that passive flow will encounter while traveling down an axon or cell?
|
Internal (axonal)
External resistance (ions around cell) Membrane resistance |
|
|
What does membrane resistance determine?
|
The amount of current that leaks across the membrane
|
|
|
What happens of the membrane resistance is lower than the axonal resistance?
|
Electricity takes the path of least resistance and therefore the current will leak out of the cell.
|
|
|
What are two ways to increase conduction velocity?
|
Increase the myelin, increase the radius
|
|
|
What does myelin increase (not speed of conduction)
|
It increases the membrane resistance to keep the current in the axon
|
|
|
Which is more effective: myleination or increase in radius?
|
Mylenation (significantly)
|
|
|
In a myelinated axon, where are the action potential's regenerated?
|
Nodes of Ranvier, bitches.
|
|
|
What is the term used for the 'jumpy' pattern of conductance between nodes?
|
Saltatory
|
|
|
What are the consequences of demyelinating an axon?
|
Slowed conduction and possibly conduction failure
|
