Action potential

this presentation explains what is action potential, how it is initiated.
it deals with short notes and brief description on the various processes that undergoes in the action potential
this presentation will help you out to summarize and conclude important points.

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2. ACTION POTENTIAL-Electro chemical changes in the neuronal cells
is action potential
Action potential is movement of electrical impulses and chemical
signals along the length of neurons.
Electrical impulses help transfer of message along the length of
neuron
Neurotransmittershelp in chemical signaling between 2 neurons
Neurons communicate with each other by the help of action
potential
Action potential arises due to difference in extracellular membrane
and intracellular membrane charges
Sodium is main extracellular cation
And potassium is main intracellular cation
The overall internal negative charge of neuronal membranes is due
to the negatively charged proteins
ACTION POTENTIAL STARTS WHEN NEURONAL CHARGE REACHES -
55 mV stimulating Voltage gated Na+ channels to open
Electrical transfer Chemical signaling
NEUROTRANSMITTERS

3. RESTING MEMBRANE POTENTIAL-internal charge of neuron
membrane at rest which is -70 mV
THRESHHOLD POTENTIAL-minimum amount of charge required to
stimulate action potential which is -55 mV
LOCAL POTENTIAL-it is the influx sodium ions due to stimulation of
mechanoreceptors that opens ligand gated sodium channels
ACTION POTENTIAL STARTS WHEN NEURONAL CHARGE REACHES -
55 mV (threshold potential) stimulating Voltage gated Na+ channels
to open
LOCAL POTENTIAL
Na+
NA+
NA+
Na+
THRESHOLD POTENTIAL
-55 mV
Na+
NA+NA+
K+K+ACTION POTENTIAL
+10 to +40
VOLTAGE GATED
SODIUM CHANNELS
VOLTAGE GATED
POTTASIUM CHANNELS

4. STAGES IN ACTION POTENTIAL
Resting membrane
potential-internal charge
of neuronal membrane at
rest which is -70 mV. There
is no stimulation at this
stage
Local potential-it arises
when sodium channels are
opened by
mechanoreceptors in
response to stimulus
Depolarization-It occurs when the local membrane potential reaches
threshold potential(-55mV). It leads to opening of voltage gated
sodium channels
When NA+ voltage gated channels are open, there is sodium influx
the internal membrane charge reaches up to +10 to +40 mV
The reversal of charge in neuronal membrane is called as
depolarization
Repolarization-it occurs when voltage gated potassium channels are
opened leading to potassium efflux, the charge again goes back to
-70 to -80 mV
Refractory period-the duration where neurons do not respond to
stimulus. No action potential can be produced in this period

5. Visual representation of action potential
When sodium enters, the internal negative charge becomes positive
When potassium exits the internal negative charge gets restored
The displacement of internal negative charge due to Na+ influx along
the neuronal membrane leads to depolarization and restoration of
negative charge due to K+ efflux leads to repolarization