Can you recall these from Nerve II?

Which of the following is the ionic basis for the rapid upstroke of action potential?

• Rapid Na⁺ influx

• Rapid K⁺ efflux

• Slow Na⁺ efflux

• Slow K⁺ influx

Which of the following is the approximate threshold potential for a typical neuron?

• -90 mV

• -70 mV

• -55 mV

• -30 mV

Which of the following is the basis for absolute refractory period of an action potential?

• Membrane potential is higher than threshold potential

• Membrane potential is lower than resting membrane potential

• Voltage-gated K+ channels are closed

• Ligand-gated channels are closed

Which of the following is a characteristic of action potential?

• The magnitude diminishes with the distance of propagation

• The depolarisation phase is dependent on net movement of Na⁺ and K⁺

• The direction of potential change always begins with depolarisation

• The duration of potential is dependent on the stimulus

Which of the following describes saltatory conduction?

• It occurs in unmyelinated neurons

• The voltage-gated Na⁺ channels are concentrated at the nodes of Ranvier

• The ionic current flows one instant at a time

• The magnitude of the current diminishes with distance

Which of the following is the first change in membrane potential that occurs at a sensory receptor?

• Action Potential

• End-plate potential

• Excitatory Post-synaptic Potential

• Generator potential

Which of the following is increases the rate of action potential conduction?

• Decreased temperature

• Decreased ECF [Na+]

• Decreased [Ca2+]

• Decreased axonal diameter

Which of the following is the mode of action of common analgesics?

• Blocks voltage-gated Na⁺ channels

• Blocks voltage-gated K⁺ channels

• Blocks the Na⁺-K⁺ ATPAse pump

• Blocks Na⁺ leak channels

Which of the following is an effect of hypernatremia on membrane potential?

• RMP becomes less negative

• The amplitude of AP increases

• Repolarisation phase of AP is longer

• Hyperpolarisation phase of AP is shorter

State one favourite fact you learned about action potentials.