chapter 7 action potential anions O- e changes in permeability associated with t
ID: 149401 • Letter: C
Question
chapter 7 action potential anions
O- e changes in permeability associated with the phases of an AP are due to the time-dependent and opening and closing of voltage-gated Na and K channels located on the PM at the axon hillock along the axon In myelinated axons these channels are numerous at the Cased by ALL-OR-NONE PRINCIPLE OF ACTION POTENTIALS - When membrane potential reaches threshold an AP is irreversibly fired: Because positive feedback opens more and more Na+ channels and shortly after opening, Na+ channels close and will be inactivated until the step Regardless of stimulus, once threshold is met the amplitude of th AP is the sameExplanation / Answer
In myelinated axons, the channels are numerous at the Nodes of Ranvier.
The Nodes of Ranvier are unmyelinated regions in myelinated axons where axolemma is exposed to extracellular spaces. They help in saltatory conduction or jumping of signals.
So, they have a very high concentration of ion channels.
Na+ channels close and will be inactivated until the repolarisation step.
Na+ channels remain inactivated until the repolarisation step of nerve transmission. This results in unidirectional transmission of nerve impulse.
All or none principle : regardless of stimulus, once threshold is met the amplitude of AP is same.
ie, if stimulation is strong enough all neurons fire maximally or do not fire at all.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.