Resting Potentials
Your neurones are like tiny electrical circuits that are constantly ready to fire. The cell body contains all the usual organelles plus the machinery for making neurotransmitters. Dendrites receive signals whilst the axon carries impulses along its length, wrapped in a fatty myelin sheath with gaps called nodes of Ranvier.
When a neurone isn't active, it maintains a resting potential of -70mV. This happens because there are more positive ions (Na⁺ and K⁺) outside the cell than inside, making the inside relatively negative.
The sodium-potassium pump works constantly using ATP to maintain this balance. It pumps 3 Na⁺ out for every 2 K⁺ in. Because the membrane is more permeable to K⁺, more potassium diffuses out than sodium diffuses in, keeping that -70mV difference.
Quick Tip: Think of resting potential like a battery that's fully charged and ready to go - your neurones are always primed for action!
