BitWithBite
Biology · Quick Reference
Lesson 9 — Nervous System Cheat Sheet
In one line: Na+ rushes in for depolarisation, K+ rushes out for repolarisation — the action potential is one continuous electrochemical event.
Key Ideas
1Dendrites receive; axon transmits; myelin speeds via Nodes of Ranvier.
2Resting: -70mV. Depolarisation: Na+ in, →+40mV. Repolarisation: K+ out, →-70mV.
3Refractory period prevents immediate re-firing.
4CNS = brain + spinal cord. PNS = somatic + autonomic.
5Sympathetic = fight/flight; parasympathetic = rest/digest.
Quick Reference
Resting potential
-70 mV
Depolarisation ion
Na+ (in)
Repolarisation ion
K+ (out)
Key neurotransmitters
Acetylcholine, dopamine, serotonin