BIO 208 Lecture Notes - Lecture 8: Myelin, Acetylcholine, Neuromuscular Junction
Document Summary
Occurs in response to an accumulation of graded potentials reaching threshold. Occurs in an all or no fashion and are of the same magnitude, so matter how strong the stimulus. A propagated change in the membrane potential. This is produced by the opening/closing of channels. Currents stimulate voltage-gated na+channels in adjacent regions of plasma membrane to open producing new aps. Reversal of the direction of new ap prevented by the absolute refractory period. (cid:498)(cid:499) adds speed to conduction of ap down the axon. Information transfer across synapse: synaptic cleft to the postsynaptic cell protein receptors on the membrane of the postsynaptic cell. Has a high threshold for triggering the voltage-gated currents. Has a refractory period must entirely complete itself before it can be. Signal transmission goes from pre-synaptic neuron across the. Neurotransmitters are released by presynaptic neuron and bind to. Ap travels down axon and arrives at synaptic knob. Ap causes ca++ voltage gates to open.
