For a second action potential to be fired an ......threshold must be reached......... the absolute refractory period.   Choice A. Lower, after B. Lower, before C. Higher, during  D. Higher,  after

The axons of myelinated neurons are imbedded in a protective covering of A. Schwann cells B. gray matter. C. nodes of Ranvier D. synaptic knobs.

25) During the refractory Period sodium ions (Na*) are pumped out of the neuron. potassium ions (K*) are pumped into the neuron. proteins are pumped out of the neuron' Both a and "b" are correct'

Threshold potential is O a. typically 10 mV to 20 mV depolarized from ("higher than") resting potential. b. the membrane potential at which a graded potential is converted to an action potential. c. both of these. d. neither of these.

(b) Use Figure Q1(b) of an action potential to answer questions (i) until (iv) below. Choose the correct letter to represent each condition. (i) The neuron cannot fire an action potential because it is in a refractory period. (ii) The membrane potential is about -70 mV. (iii) The voltage-gated Na+ channels activation gates are closed, but the inactivation gates are open. (iv) Both gates of the voltage-gated Na+ channels are open. C Threshold B A E Figure Q1 (b)

What is/are true statements about Action Potentials? Select all that apply. Group of answer choices: A. action potentials propagate down axons B. nformation is coded through the frequency of action potentials C. action potentials are slower in myelinated axons D. action potentials vary depending on the strength of the stimulus

Match the neuron part on the left to its description on the right. (1) dendrite A. a cell process that sends information (2) axon B. one of usually several cell processes that receive information (3) cell body C. the rounded part of a neuron

Action potentials are conducted more rapidlya. in small-diameter axons than in large-diameter axons.b. in unmyelinated axons than in myelinated axons.c. along axons that have nodes of Ranvier.d. All of these are correct.

Albert, the patient in question 3, takes the drug lithium, which reduces the permeability of the neuronal axolemma to Na+. Predict the effect this would normally have on his neuronal action potentials. Do you think this drug would be beneficial or harmful, considering his condition?

1. If you block calcium channels on an axon, which will not occur? A) exocytosis of neurotransmitter B) repolarization phase of the action potential C) depolarization phase of the action potential D) hyperpolarization phase of the action potential E) graded potential