On the membrane potential tracing pictured below, correctly identify and label the following waveform deflections/elements: Absolute refractory phase Individual EPSP • Individual IPSP • • Action potential depolarization • Action potential hyperpolarization • Relative refractory phase • Graded potential depolarization Graded potential repolarization • Spatial summation • Temporal summation . Graded potential hyperpolarization Presynaptic neuron A Membrane potential (mV) Presynaptic neuron B Presynaptic neuron C B. B+C Time

Correct answer: Ligand-gated ion channel don’t open until the neurotransmitter diffuses across the synapse and binds to the receptor, The calcium channels are blocked in the presynaptic cells, It takes time for the vesicular exocytosis to occur Please explain why each of the correct answer choices are correct. Thank you.

Name and describe the roles of key molecules and membrane structures in maintaining axon membrane resting potential of-70 mV Name and describe the roles of key molecules and membrane structures in propagation of axon membrane action potentials during depolarization at +35 mV  Explain why they myelin sheath of white matter neurons allows faster action potential transmission than that of neurons found in gray matter.

Describe how an action potential is generated across the axon. Make sure to explain the role of Na+ and K+ channels and pump in this process.