Neural Electricity! ⚡🧠
🔋 Resting Potential: Ready to Fire!
- -70 millivolts (mV) ➖: Neuron at rest! Negative inside, positive outside! ⚖️
- Polarized State 🧲: Like a loaded spring! Ready for action! 🎯
- Stable But Alert 😌: Waiting for the signal to fire! 📡
💥 Action Potential: The Spike!
- +50 mV Peak! ➕: Massive voltage swing! From -70 to +50! 📈
- All-or-None ⚡: Either fires completely or not at all! No in-between! 🎯
- Brief Event ⏱️: Happens in ~1 millisecond! Super fast! 💨
- The Neural "Language" 💬: How neurons communicate! Binary signal! 0️⃣1️⃣
🌊 Ionic Gradients: The Battery!
- Sodium (Na+) Outside 🔵: High concentration outside cell! Wants IN! ⬇️
- Potassium (K+) Inside 🟣: High concentration inside! Wants OUT! ⬆️
- Chloride (Cl-) Outside ⚪: Negative ions outside! 🔄
- Concentration Gradients 📊: Create electrical potential! Natural battery! 🔋
🔄 Sodium-Potassium Pump: The Maintenance!
- Active Transport 💪: Uses ATP energy! Not passive! ⚡
- 3 Na+ OUT, 2 K+ IN 🔢: Exchanges ions constantly! Maintains gradient! ♻️
- Energy Hungry 🍔: Uses 70% of brain's energy! Expensive but essential! 💰
- Keeps Battery Charged 🔋: Maintains resting potential! Never stops! ⏰
📊 EPSP: Excitatory Signals ➕
- Excitatory Post-Synaptic Potential 🚀: Makes neuron MORE likely to fire! ⬆️
- Depolarization ➕: Moves toward threshold! Less negative! 📈
- "Go" Signal 🟢: Pushes neuron toward action potential! 💚
- Sodium Influx 🔵⬇️: Na+ rushes IN! Makes inside more positive! ➕
📉 IPSP: Inhibitory Signals ➖
- Inhibitory Post-Synaptic Potential 🛑: Makes neuron LESS likely to fire! ⬇️
- Hyperpolarization ➖: Moves away from threshold! More negative! 📉
- "Stop" Signal 🔴: Prevents action potential! 🚫
- Potassium Efflux 🟣⬆️: K+ flows OUT! Makes inside more negative! ➖
🎯 All-or-None Principle
- Threshold or Bust 🚪: Must reach -55mV to fire! Below = nothing! 📏
- Full Strength ⚡: When it fires, always same intensity! 💯
- Digital Signal 🔢: Like a switch - ON or OFF! Not analog! 💡
- Frequency Coding 📻: Strength encoded by firing RATE, not size! 🔢⏱️
🧮 Integration: The Math!
- Summation 🧮: Cell adds up ALL inputs! EPSPs + IPSPs! ➕➖
- Temporal Summation ⏰: Rapid signals from SAME synapse add up! 📈
- Spatial Summation 🗺️: Signals from DIFFERENT synapses combine! 🔗
- Decision Point 🤔: If total > threshold → FIRE! ⚡
🔑 Key Takeaways
- Resting potential is -70mV! Ready state! 🔋➖
- Action potential peaks at +50mV! 💥➕
- Ionic gradients create the battery! 🌊🔋
- Sodium-potassium pump maintains gradients! 🔄💪
- EPSP excites, IPSP inhibits! ➕➖
- All-or-none law! Digital, not analog! 🎯⚡
- Integration determines if neuron fires! 🧮🔥