PRACTICE QUESTIONS

1. In treating critically ill patients with intravenous fluids, which two ions are most important to the neuronal membrane potential?

a. Na^t and CΓ

b. K⁺ and CΓ

c.

d. K⁺ and Ca²⁺

e. Na* and K⁺

2. The energy required by the Na*,K¹ neural membrane pump is derived from ATP. In the neuron, this energy results from the nearly exclusive metabolism of oxygen and:

a. Amino acids

b. Fatty acids

c. Glucose

d. Glycogen

e. Proteins

3. If the number of IPSPs on the dendritic membrane decreases while the number of EPSPs remains the same, what will happen to the action potentials on that neuron?

a. Probability of triggering action potentials increases.

b. Probability of triggering action potentials decreases.

c. Probability of triggering action potentials remains unchanged.

d. Action potentials would be eliminated.

e. Action potentials would be conducted with increased velocity.

4. During an excitatory postsynaptic potential in a neural membrane, which of the following is the most important ion flow?

a. Sodium ions diffuse out of the cell.

b. Sodium ions diffuse into the cell.

c. Potassium ions diffuse out of the cell.

d. Potassium ions pumped in by the Na*,K⁺ pump.

e. None of the above.

5. Choose the incorrect statement below:

a. Conduction velocity of action potentials is slower in myelinated than in unmyelinated axons.

b. Conduction velocity of action potentials is faster in myelinated than in unmyelinated axons.

c. In saltatory conduction of action potentials, the action potential seems to jump functionally from node to node (nodes of Ranvier).

d. Action potentials are of equal magnitude at the beginning and at the end of an axon.