The Properties of Reflex Actions

Reflex actions are automatic responses to specific stimuli, thus not requiring conscious thought.
They act as a protective mechanism, allowing rapid reactions to potential danger.
They involve three types of neurones: the sensory neurone, relay neurone, and motor neurone.
The pathway these neurones create from receptors to effectors is known as a reflex arc.
The process starts when a stimulus, such as heat, triggers receptors at the end of a sensory neuron.
An electrical impulse travels along the sensory neuron to the CNS (Central Nervous System).
The relay neuron, located in the CNS, transmits the impulse to the motor neuron.
This signal then triggers an effector (muscle or gland) to perform an appropriate response.
Reflex actions are very fast due to the short pathway involved.
Since the brain is not involved in the initial decision, these responses are involuntary.
Practical examples include reactions to touching a hot surface, eating food that is too spicy or bright light causing pupil constriction.
A well-known reflex action is the knee-jerk response, observed when a light tap causes the leg to jerk forward involuntarily.
Understanding reflex actions aids in the comprehension of nervous system function and coordination in organisms.