21.--Which of the following statements regarding the propagation of an action po

Question

21.--Which of the following statements regarding the propagation of an action potential is most accurate? a) sodium ions that flow into the cell during one action potential diffuse and induce a new action potential in a neighboring membrane region; b) action potentials will propagate in all directions along an axon since sodium ions diffuse in all directions; c) sodium ions do not diffuse from the axon hillock into the perikaryon, thus ensuring one - way propagation of the action potential; d) action potentials propagate only toward cell membranes that are experiencing a refractory period; e) new action potentials are generated by depolarizations to -65 mv. A postsynaptic cell a) must always be a neuron; b) possesses many synaptic vesicles near the synapse; c) releases neurotransmitter result of the influx of calcium; d) may possess function as chemically regulated gates; e) always contains a membran bound acetylcholinesterase. receptor proteins that 23. Q The increase in excitability of a postsynaptic neuron following repeate stimulation is called a) inhibitory post synaptic potential; b) presynaptic inhibition; c) synaptic potentiation; d) excitatory post synaptic potential; e) neuromodulation. 24. Biogenic amines a) are always found in the CNS; b) are never found in the CNS; c) are constructed from short chains of amino acids; d) are metabotropic (indirect) in function; e) include the neurotransmitter acetylcholine. Which of the following does not appear to be a structural class of neurotransmitter? a) acetylcholine; b) disaccharides; c) peptides; d) purines; e) peptides. 25.

Explanation / Answer

21) the correct option is option (a)

Depolarization occurs when the membrane potential shoots from - 70mV to 30mV . This takes place due to the diffusion of sodium ions inside the membrane which changes the polarity hence the action potential propagates...!!

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