BIOM20002 Lecture Notes - Lecture 9: Motor Neuron, Axon Hillock, Myocyte
Larger axon = faster conduction due to less resistance to ions
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100 billion neurons in the brain. 100 trillion synapses
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Intensity of signal detected by receptor translates into how frequently AP are sent
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9 Simple circuits
Saturday, August 2, 2014
2:10 PM
HSF Page 1
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HSF Page 2
Document Summary
Larger axon = faster conduction due to less resistance to ions. Intensity of signal detected by receptor translates into how frequently ap are sent. Ca2+ floods in down a huge concentration gradient. Sometimes the nt receptor is an ion channel. Some signals are stimulatory (e. g. na channel opens). Influx of, say sodium, in post synaptic neuron causes a graded potential. The cell receives all the graded potentials and decides whether to fire/not fire an ap. A synapse near here will have a large impact on mp - priority signalling. There are likely to be na channels near the red excitatory neurons. Likely to be k channels near black inhibitory neurons. Excitatory post synaptic potential (epsp): depolarising signals generated by cns synapses. In the bottom graph is the action potential vs time. Note they are all at the same height. The epsp and ipsp may never be registered by the hillock since the graded potential decays.
