Nerve Impulse Flashcards
(17 cards)
What is the action potential in nerve cells?
A potential difference (PD) generated by changes in ion concentrations inside and outside the nerve cell
What triggers the action potential?
Depolarisation of the nearby membrane changing the PD to the threshold potential
What happens if the threshold potential is not reached?
Nothing happens
How long does it take for a new action potential to be generated in the same section of membrane?
About 5 milliseconds
What is the resting potential range for nerve cells?
Between -60 and -70 mV
What occurs during repolarisation?
K+ gates open, K+ diffuses out of the cell taking positive charge with it
What is the threshold potential?
The membrane potential that must be reached to trigger an action potential
What is the role of sodium (Na+) during depolarisation?
Na+ gates open, allowing Na+ to diffuse into the cell carrying positive charge
What is hyperpolarisation?
When the membrane potential becomes more negative than -60 to -70 mV
What is saltatory conduction?
The process where nerve impulses jump from one node of Ranvier to the next
Where can depolarisation occur in a myelinated nerve fibre?
At the nodes of Ranvier
What effect does myelination have on nerve impulse transmission?
It allows impulses to travel faster and longer distances
Fill in the blank: The action potential is a _______ caused by ion concentration changes.
What ions are primarily involved in generating an action potential?
- Sodium (Na+)
- Potassium (K+)
True or False: An action potential can be generated in any section of the nerve membrane at any time.
False
What happens to Na+ gates after depolarisation?
Na+ gates close
What happens to the cell after K+ gates close?
K+ moves back into the cell through non-voltage gated channels
