There is one simple type of brain activity in which a stimulus is followed by an instantaneous action. This is reflex action in action. Marshall Hall, a 19th-century English neurologist, coined the term reflex (from Latin reflexus, “reflection”) to describe the muscles’ ability to reflect a stimulus in the same way that a wall reflects a ball thrown against it. Hall defined reflex as the automatic response of one or more muscles to a stimulus that stimulates an afferent neuron. The word is now used to denote an action that is an inborn central nervous system activity that does not include consciousness and in which a specific stimulus causes a stereotyped, instantaneous response of muscle or gland by activating an afferent neuron.
What is Reflex Action
When you contact a hot surface by accident, your hand quickly retracts. It’s almost as if it’s a pre-programmed action that you don’t have to think about. This is known as reflex action in scientific language. Numerous neuronal pathways known as reflex arcs intervene on an impulse before it reaches the brain, resulting in such actions. These behaviours can be passed down from parents or learned during the course of a person’s life. To learn more about the physiology and importance of reflex action, read the article.
What is Reflex Action and Examples
The entire mechanism of reflex response is set up in such a way that the brain has no conscious control over it. The peripheral nervous system is stimulated, and the response to this peripheral nerve stimulation is involuntary. The reflex movements are controlled by the spinal cord and the brain stem in a reflex action.
Examples:
- The pupil of the eye changes size when light acts as a trigger.
- When a pin is pricked in the hand or leg, it causes a sudden jerky withdrawal.
- Because of irritants in the nasal passages, you may cough or sneeze.
- Knees jerk in response to a punch or pounding on the leg.
- The act of abruptly removing one’s hand from a sharp object.
- When an insect comes very close to the eyes, it causes sudden blinking.
Some critical components are involved in the reflex action process as a whole. Receptor organs, sensory neurons, nerve centers, linked neurons, motor neurons, and effector neurons are the different types of neurons.
The stimuli are detected by the receptor organs. They are located on the organs of perception. The sensations are carried to the spinal cord by afferent neurons, also known as sensory neurons. The sensory neurons are found in the ganglia of the spinal cord.
What is Reflex arc with Example
A reflex arc is the path travelled by nerve impulses during a reflex. In higher animals, the bulk of sensory neurons synapse in the spinal cord rather than flowing straight into the brain. This characteristic allows reflex actions to happen quickly by activating spinal motor neurons without having to wait for signals to be routed through the brain; nonetheless, sensory input is still received by the brain throughout the reflex movement.
The majority of reflex arcs are made up of merely three neurons. A stimulation, such as a needle stick, stimulates the skin’s pain receptors, which cause a sensory neuron to fire an impulse. This goes to the spinal cord, where it connects with a connecting neuron called the relay neuron in the spinal cord via a synapse.
The relay neuron then forms a synapses with one or more motor neurons, which convey the impulse to the limb muscles, causing them to contract and draw away from the sharp object. Even though the brain can sometimes interfere with reflex action, reflexes do not require it.
Example:
When we inadvertently contact something hot, we experience a basic reaction arc.
Conclusion
A reflex action is an unintentional and unconscious response of effectors to a stimuli. We immediately remove our hand from a hot object stimuli, for example. Other examples from everyday life include salivating after seeing food, sneezing, blinking, and yawning. Reflex Arc: The reflex action route is referred to as the reflex arc. When we touch anything hot, the stimulus travels down the sensory nerve to the spinal cord. The motor neuron sends a signal to the hand muscles to contract, and the hand is removed from the hot object in a fraction of a second. Reflex action is an unconscious, instinctive response by the body to external stimuli. Reflex action is a response to the environment that is initiated by the body without the involvement of the brain. As soon as the stimulus is activated, impulses are sent to the spinal cord. The target organs receive an instantaneous response without the involvement of the brain. Reflex action is the term for this phenomena. Only then do impulses reach the brain. Conscious responses are made later.