Generation Of A Nerve Impulse Flashcards
What does a resting neuron contain? And what does this mean?
Potential energy - a DIFFERENCE in electrical charge inside/outside a cell
What is another name for a nerve impulse? What is a nerve impulse?
Action potential
CHANGE in electrical charge inside/outside a cell
Define resting membrane potential and identify the mV:
Difference in electrical charge inside/outside a RESTING NEURON
Negative 70mV
What is a resting neuron called?
Polarised
In a polarised neuron, what is the charge of the extra cellular fluid and why?
Positive - sodium (NA2+) ions
What does the intracellular fluid of a polarised neuron contain? What charge is it and why?
Large negative ions and potassium (K+) ions
Negatively charged, the negative ions outweigh the potassium ions
What is the sodium potassium pump?
ACTIVELY pumps K+ into the cell and NA2+ put of the cell
What is the minimum mV needed to generate a nerve impulse? What does thie bring the membrane potential to?
15mV
Negative 55mV
What channel does a stimulus open on a polarised neuron? What happens when this channel opens? What does the intracellular fluid become?
NA2+ Voltage-Gated Channel
NA2+ ions flow into the cell
More positive
What is depolarisation?
Reversing changes
What do the NA2+ ions do when they enter the cell? What does this cause?
Diffuse in the cytoplasm
Causes adjacent NA2+ VGC to open meaning an influx of NA2+ ions enter swapping the charges of intra/extracellular fluids
- intra = positive
- extra = negative
Why is the extracellluar fluid negative during depolarisation?
Absence of positive NA2+ ion
And/or intracellular is more positive
Why is the intracellular fluid positive during depolarisation?
Influx of NA2+ ions (due to NA2+ VGC opening from a stimulus) outweighs the large negative ions
What is repolarisation?
The RETURNING of intra/extracellular fluids of their original charges
During repolarisation, what does the presence of NA2+ ions stimulate to open?
Potassium Voltage-Gated Channels
