Please answer ALL parts of the question 3 Label the diagram

Please answer ALL parts of the question!

3. Label the diagram of an action potential, and explain why this condition can cause muscle weakness Label the depolarization and repolarization phase of the muscle action potential, and indicate the ion permeabilities on your drawing. (6 pts) phase increased permeability to +30 phase - Increased permeability to -90 2 Time

Solution

Depolarization phase - increased permeability to sodium ion (Na⁺) into the cell. Cells normally present in polarized state and maintain resting potential -70 mV. When a stimulus applied then the permeability to sodium ions increases due to which sodium ion enters into the cells and depolarize the cells as we know sodium has positive charge.

Repolarization phase - Increased permeability to potsaaium ion (K⁺) out to the cell. After attainment of peak level of depolarization, permeability to potassium ion increases due to which potassium ions come out from the cell which repolarize the cells again.

Here the resting membrane potential is highly negative as it is -90 while the normal resting membrane potential is -70. When resting membrane potential is highly negative, it will require high stimulus to attain threshold value (-55mV) to generate an action potential. Hence this highly negative resting membrane potential results in muscle weakness.