Section: Biological and Biochemical Foundations of Living Systems

15) All all of the following are true regarding the function of neurons EXCEPT:

1. Hyperpolarization at the end of an action potential is one mechanism by which neurons limit the rate at which action potentials may fire.
2. The flow of sodium into the neuron depolarizes the membrane in the first phase of an action potential.
3. The transmitting neuron secretes neurotransmitters into the synaptic cleft from its dendrites.
4. An action potential is initiated when the axon hillock reaches the threshold potential.

This question is testing your understanding of the function of action potentials and neuronal transmission of signals. Here, (A), (B), and (D) are all true. Since this is an “EXCEPT” question, the right answer is the one false statement: choice (C). A neuron secretes neurotransmitters from its axon, not its dendrites.