PSYCH 1 Lecture Notes - Lecture 20: East Los Angeles College, Ion Transporter, Ion Channel
Document Summary
Action potential brief electrical charge of axon caused by unequal distribution if charge. Is an all or none event (happens or doesn"t) Ion channel: controls entry and exit of sodium and potassium. Ion transporter: actively transports ion in/out of cell. In resting state, membrane is depolarized (uneven charge distribution) Sodium/potassium pumps use atp to transport na+ out and k+ in. Action potential (firing of a neuron) is caused by opening of some ion channels allowing positive ions to enter axon reversing the membrane potential at that location (charge). This process causes other channels to open nearby, causing reversal at that point. 1) sodium channels open na+ ions enter reversing membrane potential (inside become positive) 2) potassium channels open k+ ions leave restoring membrane potential. 3) ion transporters pump sodium and potassium back into membrane. Binding of neurotransmitter to receptor can trigger action potential in postsynaptic neuron restoring normal balance (enough receptors are occupied)
