posted by carol .
16 .Action potentials are generated along a neuron because __________.
A.of cytoplasmic streaming within the neuron
B.depolarization of the membrane at one point causes an increase of permeability to sodium at the next point
C.they are pulled along by positive-negative attraction
D.the neuron cytoskeleton conducts electricity as long as an ion gradient is maintained by the sodium-potassium pump
E.of all of these factors
17 .Which one of the following statements about the transmission across a typical chemical synapse is NOT true?
A.Neurotransmitter molecules are stored in vesicles in the synaptic knobs.
B.Action potentials trigger chemical changes that make the neurotransmitter vesicles fuse with the plasma membrane of the sending neuron.
C.Vesicles containing neurotransmitter molecules diffuse to the receiving neuron's plasma membrane.
D.Neurotransmitter molecules bind to receptors in the receiving neuron's plasma membrane.
E.The binding of neurotransmitter molecules to receptors transmits an impulse across a synapse.
18 .How are neurons structurally adapted to chemically transmit impulses to neighboring neurons?
A.Synaptic knobs contain neurotransmitter substances within synaptic vesicles.
B.They have numerous nodes of Ranvier.
C.They have numerous dendrites.
D.They have Schwann cells that surround axons.
E.None of the above is correct.
a b c