Objectives

• Explain how a membrane becomes polarized

• Describe the events that lead to the generation of an action potential

• Inner surface of cell membrane is usually negatively charged

• Uneven ion amounts on either side​​

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Polarization

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• ​Na+ outside (greater concentration) and K+ inside (lesser concentration)

• Large negetively charged ions (PO4-3​) that cannot diffuse.

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Ion Distribution​

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Electrical Potential

Hypothetical Neuron​

• The Electrical potential is achieved by the movement of Na+ and K+.

• ​Before it has a charge, it releases K+ ions quicker than Na+ is allowed in and thus polarization is achieved.​

• This creates resting potential

• ​Excitable

• Sensory neurons designed to respond to changes around

• Depolarization-Decrease in charge​

Potential Changes

• ​As Na+ enters it makes it less charged

• ​If it reaches the threshold, Na+ ion channels open on the axon. triggering action potential

Action Potential