Reflex Arc

Reflex Arc: How the simplest reflex works

The reflex arc is a nerve circuit that plays an important role in the implementation of the reflex. A reflex is a quick and unconscious response of the body to an external or internal stimulus. The simplest reflex arc consists of two neurons: sensory and motor.

The first neuron, also called an afferent, is located in the spinal ganglion or sensory ganglion of the cranial nerve. This neuron has peripheral processes that are sent as part of the corresponding spinal or cranial nerves to the periphery, where they end in a receptor apparatus that perceives irritation.

When the receptors are exposed to a stimulus, such as when a hammer falls on the knee, the receptors send information to an afferent neuron, which transmits it to the spinal cord.

In the spinal ganglion, the information passes to a second neuron, called an efferent neuron. It has its body in the spinal ganglion and peripheral processes that are directed to the muscles or glands.

When a simple reflex occurs, such as the patellar reflex, only two neurons are involved in this process. When an afferent neuron transmits information to the spinal cord, the efferent neuron instantly transmits a signal to the muscles, causing them to contract. As a result, the knee will quickly bend.

Other reflexes require the interaction of several interneurons of the reflex arc. For example, when we feel pain, the signal travels from the receptors through several neurons to the spinal cord, where it is processed and transmitted to the brain for further processing.

Thus, the Reflex arc is an important component of our nervous system, allowing us to quickly and effectively respond to external and internal stimuli. Understanding the mechanism of the Reflex arc helps to better understand the principles of functioning of our nervous system and can be useful in the treatment of various diseases associated with impaired reflexes.

The neural circuit involved in the reflex. The simplest reflex arc consists of 2 neurons: sensory and motor. The body of the first neuron is located in the spinal ganglia or sensory ganglia of the cranial nerves. Peripheral processes of cells are directed to the spinal or cranial nerves to the periphery and end with receptors that perceive irritations. In the process of a simple reflex, for example, the patellar reflex, only 2 neurons can participate. More complex reflexes require the interaction of several interneurons.

Reflex arc

The reflex arc is one of the main elements of the reflex circuit; it represents a neural pathway along which the signal passes from one neuron to another. The arc includes a sensory neuron (afferent), an interneuron and a motor neuron. The process of perceiving a signal and transmitting it to