PS263 Chapter Notes - Chapter 2: Reflex Arc, Inhibitory Postsynaptic Potential, Excitatory Synapse
Document Summary
Reflex arc: the circuit from sensory neuron to muscular response (*explained in ch1 notes) Speed of a reflex & delayed transmission at the synapse: speed along an axon is faster than along a reflex arc. Temporal summation: repeated stimuli within a short time frame: ex. Excitatory postsynaptic potential: a graded depolarization results from a flow of na ions into the neuron if an epsp does not cause the cell to reach threshold, the depolarization decays quickly. Spatial summation: synaptic inputs from several locations combine their efforts on a neuron, ex. One pinch did not invoke reflex, pinching 2 points did: combining excitations exceeded the threshold & produced an action potential. Inhibitory synapses: @ these synapses, input from an axon hyperpolarizes the postsynaptic cells. Inhibitory postsynaptic potential: temporary hyperpolarization of a membrane. Relationship among epsp, ipsp, and action potential: spontaneous firing rate: a periodic production of action potentials even without synaptic input, epsps: increase frequency of action potentials.
