REFRACTORY PERIOD

Reactivity of Neurons: The Refractory Period

Neurons are capable of rapid, precise communication of information throughout the body. This communication is enabled by the ability of neurons to rapidly respond to stimuli from other cells through an electrochemical process. However, this reactivity is not unlimited, and neurons are subject to a refractory period, during which they cannot be re-stimulated. This article will discuss the concept of the refractory period, its importance to the functioning of neurons, and the various factors that influence its duration.

The refractory period is a period of time during which a neuron is unable to respond to a stimulus. This period is divided into two distinct phases: the absolute refractory period (ARP) and the relative refractory period (RRP). During the ARP, the neuron is completely inactive and cannot be re-stimulated, regardless of the magnitude of the stimulus. During the RRP, the neuron is still inactive but can be re-stimulated by a stimulus of greater intensity. After the refractory period has ended, the neuron can again respond to input from other cells (Kandel et al., 2000).

The refractory period is an important component of the function of neurons, as it ensures that neurons are not overstimulated. Without the refractory period, neurons would continue to respond to a stimulus until it was no longer present. This could lead to a buildup of electrical charge in the neuron, which could eventually cause it to become non-functional. The refractory period also provides a safety mechanism that prevents neurons from responding to stimuli that are not relevant to their function (Kandel et al., 2000).

The duration of the refractory period is determined by a number of factors, including the type of neuron, the intensity of the stimulus, the membrane potential of the neuron, and the presence of inhibitory substances. Neurons with a higher resting potential tend to have a longer refractory period, as do neurons that are exposed to higher intensity stimuli (Kandel et al., 2000). Inhibitory substances, such as GABA, can also reduce the duration of the refractory period by decreasing the neuron’s threshold for responding to stimuli (Kandel et al., 2000).

In conclusion, the refractory period is an important component of the function of neurons, as it ensures that neurons are not overstimulated and allows them to respond only to relevant stimuli. The duration of the refractory period is determined by a number of factors, including the type of neuron, the intensity of the stimulus, the membrane potential of the neuron, and the presence of inhibitory substances.

References

Kandel, E.R., Schwartz, J.H., Jessell, T.M., Siegelbaum, S.A., & Hudspeth, A.J. (2000). Principles of Neural Science (4th ed.). New York: McGraw-Hill.