PSY 381 Lecture Notes - Lecture 3: Dynamic Equilibrium, Ligand-Gated Ion Channel, Threshold Potential
Document Summary
The cell membrane is a lipid bilayer that by it self does not allow current to flow into or out of the neuron. (semi-permeable) When atoms or molecules flow from a region of high concentration to a region of low concentration, they are said to be moving down their concentration gradient. The sodium-potassium pump uses significant metabolic energy to continuously push sodium ions out of a neuron while pulling potassium ions in, in a ratio of 3 sodiums out for 2 potassiums in. Graded potentials on the neural cell membrane can add up in analog fashion to trigger an action potential in the axon. Voltage-gated channels are activated by a change in membrane potential. Action potentials all look alike (have the same amplitude and waveform) and act like digital coding in the nervous system. Depolarization leads to generation of an action potential. Hyperpolarization makes the interior of a cell more negative.
