Biology 1st Edition by Jerome Krueger, Kendra Hill, Robert Noyd

Exercise 5

A nerve impulse called a(n) _________ is caused by the movement of _________ ions from outside the nerve cell membrane to inside, creating an electrical gradient wave that sweeps down the cell (refer to Fig. ).
A) neurotransmitter; hydrogen
B) myosin agent; helium
C) action potential; sodium
D) contraction; zinc
Figure Action potential. This cutaway of an axon shows events at the plasma membrane of the neuron. Large proteins (purple) use energy to move potassium (K + ) and sodium (Na + ) ions rapidly across the membrane against their concentration gradients. This helps maintain a charge difference between the inside and outside of the neuron, which sets the stage for the rapid creation of an electrical signal, or action potential.