Normal Channel
Open → Inactivate → Repolarize → Recover
State
Resting
Faulty Inactivation
Leaky Rest → Open → Failed Inactivation
State
Leaky Rest
In simple terms: Sodium (Na+) rushes into a muscle cell to start a contraction, and Potassium (K+) flows out to stop the signal and reset the cell for the next squeeze.
An interactive, science-grounded animation showing how a healthy skeletal muscle sodium channel opens and inactivates normally, versus a Hyperkalemic Periodic Paralysis (HyperKPP) channel with faulty inactivation that leaves the fiber persistently depolarized. Watch Na+ influx and K+ efflux across the membrane, and how that differs between states.
How to read this: In the healthy panel, Na+ enters only when the channel opens, then the inactivation gate shuts and K+ exits to repolarize. In HyperKPP, the channel is slightly leaky at rest, opens normally, then fails to fully inactivate; Na+ keeps trickling in and K+ accumulates outside, leaving the membrane stuck partially depolarized.