11) When a neuron is at its “resting potential,” which of the following is true about the concentration of sodium ions?

A) Sodium ions have a greater concentration inside the neuron’s cell membrane.

B) Sodium ions have a greater concentration outside the neuron’s cell membrane.

C) The sodium concentration is the same outside and inside the neuron’s cell membrane.

12) Part of the reason for the charge difference inside and outside a neuron’s membrane is:

A) excess potassium outside the membrane.

B) excess sodium inside the membrane.

C) negatively charged proteins inside the membrane.

D) positively charged proteins inside the membrane.

E) positively charged proteins outside the membrane.

13) A section of a neuron’s membrane becomes temporarily positive on the inside when:

A) ion channels open and sodium ions rush in.

B) ion channels open and potassium ions rush in.

C) negatively charged proteins exit the cell.

D) neurotransmitters enter the cell.

14) Inrushing sodium ions trigger the opening of nearby channels and movement of sodium inward at that neighboring section of the membrane. What is occurring?

A) normal resting potential

B) an action potential

C) neurotransmitter release

D) protein movement

15) Which statement best describes how one neuron stimulates another?

A) Sodium ions jump across to the next neuron’s membrane.

B) The neurons are physically connected, so the action potential continues movement.

C) Calcium ions diffuse across the synapse.

D) Neurotransmitter molecules diffuse across the synapse.

16) A drug that causes potassium to leak out of the neuron would:

A) make it harder to trigger action potentials in the neuron.

B) cause the inside of the neuron to become more positive.

C) cause the outside of the neuron to become more negative.

D) make it easier to trigger action potentials in the neuron.

17) Spinal nerves emerging from the spinal cord are named for:

A) their basic function.

B) the organ they supply.

C) the portion of the vertebral column around them.

D) strictly the number sequence 1—30.

18) Axons of motor neurons first leave the spinal cord through the:

A) spinal nerve.

B) ventral roots.

C) dorsal roots.

D) dorsal root ganglion.

19) In a reflex such as the “knee jerk” or patellar reflex, the efferent signal travels through the:

A) spinal cord.

B) motor neuron.

C) sensory neuron.

D) interneuron.

20) Any collection of nerve cell bodies in the PNS is called a:

A) ganglion.

B) afferent nerve.

C) efferent nerve.

D) dendrite.