KP351 Lecture Notes - Lecture 1: Resting Potential, Neuromuscular Junction, Motor Neuron
20 Mar 2020
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Stimulus that creates a membrane change in ion between inside and outside a cell and it will propagate along the neuron to connect to something. Signal will not propagate if signal is not strong enough. Motor nerve to muscle is releasing acetyl choline. What is needed to generate a muscle contraction: excitatory input (pre-synaptic, trigger zone, signal; propagates along axon, out put, excitation travels to post-synaptic cell. What happens once the signal reaches the muscle (post-synaptic cell) ** Post synaptic is muscle pre synaptic is a motor neuron. Inside of cell reference to outside of cell: resting membrane potential / electrochemical equilibrium. When stimulus arrives it creates a disequilibrium: threshold. -70 is usually threshold: all or nothing phenomena. Depolarization cause vg ca channels to open. Changes in excitability of the postmen cell. Bottom of motor neurone but top of neuromuscular junction. Increase in calcium allows vesicles to fuse with the membrane. Vesicles fusing releases them into synaptic terminal.
