Interactive Membrane Potential Simulator

Welcome to the Interactive Membrane Potential Simulator! This educational tool allows you to visualise and calculate how different ions (Potassium, Sodium, and Chloride) contribute to the electrical charge across a cell membrane.

Whether you are a biology student, a neuroscience enthusiast, or just curious about how cells generate electrical signals, this simulator breaks down the complex math into an interactive, visual experience.

🌟 Features

• Real-Time Animation: Watch particles representing K+, Na+, and Cl− ions move across the extracellular (outside) and intracellular (inside) spaces.
• Interactive Controls: Adjust temperature, ion concentrations, and membrane permeabilities using simple sliders.
• Live Calculations: Instantly see the results for each ion's Nernst Equilibrium Potential and the cell's overall Goldman-Hodgkin-Katz (GHK) Resting Membrane Potential.
• Visual Flux Dynamics: The animation visually represents the probability of ions crossing the membrane based on the concentration gradients and permeabilities you set.

🚀 How to Use

1. Observe the Canvas: The top half of the screen shows the extracellular space, and the bottom half shows the intracellular space. The coloured dots represent different ions moving around.
2. Adjust the Sliders:
   • Temperature: Affects the thermodynamic energy of the system.
   • [Ion] out / [Ion] in: Changes the concentration (in milli-molar, mM) of ions on either side of the membrane.
   • Permeability: Changes how easily a specific ion can pass through the cell membrane.
3. Read the Results: Look at the bottom right panel to see the calculated electrical potentials measured in millivolts (mV).

🧮 The Science

This simulator uses two fundamental equations in cellular neurobiology to calculate the voltages based on your slider inputs.

Constants Used

Before calculating the potentials, the code defines several physical constants:

• R (Gas Constant): 8.314 J/(mol·K)
• F (Faraday Constant): 96485 C/mol
• T (Absolute Temperature in Kelvin): Calculated as Celsius+273.15

The thermal voltage factor used in both equations is calculated as: Factor=RTF×1000 (Note: The multiplier of 1000 converts the final result from Volts to millivolts).

1. The Nernst Equation

The Nernst equation calculates the Equilibrium Potential for a single type of ion. This is the exact electrical voltage that would perfectly balance the chemical concentration gradient, resulting in zero net flow of that specific ion.

2. The Goldman-Hodgkin-Katz (GHK) Equation

While Nernst calculates the potential for one ion, a real cell membrane is permeable to multiple ions at once. The GHK equation calculates the overall Resting Membrane Potential (Vm) by taking into account the concentration gradients and the relative permeabilities (P) of all three major ions simultaneously.