PSC 101 Lecture Notes - Lecture 3: Poison Dart Frog, Electrical Synapse, Chemical Synapse
Document Summary
Nerve impulses which are brief but large changes in membrane potential. Patterns of action potentials carry information to target cells. Neuronal activity and behavior is based on the movement of ions into and out of neurons. In a normal state, sodium is kept out of the neuron and potassium is kept inside the cell(sodium-potassium pump) Action potentials are produced by the movement of sodium ions into the cell. After reaching a peak of 40mv, potassium channels are opened and potassium rushes out of the cell which results in hyperpolarization. Sodium is pumped out and potassium is pumped in to restore the cell into its resting stage. With closely spaced stimuli, only the first is able to trigger an action potential the membrane becomes refractory(unresponsive) to later stimuli. Two phases: absolute refractory phase no action potentials are produced, relative. Refractory phase only strong stimulation can produce an action potential.
