H/W U4_Ch12_P4

If acetylcholinesterase became mutated and nonfunctional, what would be the immediate result?

Acetylcholine would build up in the synaptic cleft.

During depolarization, which of the following statements about voltage-gated ion channels is TRUE?

Na+ gates open before K+ gates.

Which of the following statements about the resting membrane potential is TRUE?

The exterior of the cell has a net positive charge and the interior has a net negative charge.

Which of the following characteristics of action potentials can vary?

The frequency of action potentials.

The nerve impulse is an electrical current that travels along dendrites or axons.

True

The sodium-potassium pump is involved in establishing the resting membrane potential.

True

At the synaptic knob, voltage-gated ______________ channels open, thereby stimulating the synaptic vesicles to release their neurotransmitters by exocytosis.

calcium

On a graph of an action potential, the small depolarizations that lead to threshold are from

excitatory postsynaptic potentials (EPSPs).

When voltage-gated sodium channels are open, sodium flows _____________ the neuron making the inside of the cell more _______________.

into; positive

Depolarization occurs because

more Na+ diffuse into the cell than K+ diffuse out of it.

The following information best describes the _____________ phase of an action potential.

repolarization