NROSCI 1000 Lecture Notes - Lecture 5: Gap Junction, Chemical Synapse, Neuroglia
Document Summary
As the ap propagates down the axon, it is non decremental does not change shape. Lots of vgic (na+) at the nodes of ranvier. Due to high resistance internodal regions, current jumps from node to node. Way faster than conduction in an unmyelinated neuron. 1000 synapses per neuron; 10^14 synapses in a brain. Each spine on a dendrite is a possible location of a synapse. Electrical synapses: allow passive flow of current directly thru gap junctions. Allow current to flow directly through gap junction. Paired channels called connexons that create pores for ions to diffuse. Fast, synchronize networks of neurons, communication between glial cells. Delayed transmission: 1-5ms between action potential and postsynaptic potential. Mostly because more things have to happen takes time to fuse and diffuse fuse and diffuse. Benefits: flexibility; diversifies the repertoire of neural responses. Calcium entry into the nerve terminal is the trigger for. Ap invades presynaptic terminal --> depolarization of terminal opens voltafe gated ca2+ channels.
