Please only answer if you are an expert on the subject. Please clearly explain y
ID: 3518080 • Letter: P
Question
Please only answer if you are an expert on the subject. Please clearly explain your answer and step process. thank you
Animal physiology neuro phys question: Chemical messages bind to 10 ligand-gated ion channels on the dendrites and cell body of a motor neuron. At the axon hillock, 7 of these ligands produce excitatory graded potentials (i.e. depolarizing, called EPSPs) of 3mV each and the other 3 produce inhibitory graded potentials (i.e. hyperpolarizing, called IPSPs) of 5mV each. The threshold potential of this neuron is -55mV (resting membrane potential is -70mV). Will an action potential be produced? Assume that all impulses get to axon hillock at the same time and there is no decay in signal. To get full points you need to show all the math to justify your answer.
Explanation / Answer
Answer
The threshold potential is -55mV.
The excitatory graded potential produced by 7 ligands = 7 × 3 = 21 mV.
The inhibitory graded potential produced by 3 ligands = 3× 5 = 15.
So potential produced at the synapse to cause action potential = 21 - 15 = 6 mV.
The potential that is 6 mV is greater than the threshold potential. So the action potential is produced.
The 6mV causes the depolarization by opening depolarizing channels. So the inhibitory neurotransmitters produce less likely to cause action potential at postsynaptic membrane but excitatory neurotransmitter have more and fast action potential in the postsynaptic membrane.