PHSL-P 416 Lecture Notes - Lecture 23: Active Transport, Electrical Synapse, Botulinum Toxin
Document Summary
Synapse: : joining of 2 neurons, with action potential, communication occurs. Presynaptic neuron: prior to synapse, sends info from potential to neuron 1. Post synaptic: neuron after synapse, recieves info from pre-synaptic neuron, neuron 2. Electrical synapse: (gap junctions: allows direct sharing of ions between " Therefore allows direct transmisson of graded potentionals(directly shared between neurons) -> assuming there is a lot of ions for each to reach threshold. Chemical synapse: no direct connection(small space in btw neurons, uses neurotransmitters to get from 1 neuron to the next, calcium triggers neurotransmitter release. Once calcium ca+ flows in, vesicles migrate to axon terminals. Important for effective neurotransmitter release(very quickly: occurs before arrival of action potential, when ca+ is released, they exocitise their contents. Botox: neurons rebuild the snares, botox injections destroy snares in motor neurons: neurotransmitter isn"t released so you lose ability to directly contract the muscle.
