Question
What is reflex action? Explain reflex action with an example.
Answer
Reflex action is an involuntary and rapid response to a stimulus that occurs automatically without conscious thought or effort. It is a protective mechanism that helps prevent injury or damage to the body by quickly and automatically responding to potential environmental threats.
Here is an example of a simple reflex action, the knee-jerk reflex:
- When a doctor taps the patellar tendon just below the kneecap with a rubber hammer, it stretches the quadriceps muscle in the front of the thigh.
- This stretch is detected by sensory receptors called muscle spindles, which send a signal through sensory neurons to the spinal cord.
- In the spinal cord, the sensory neuron synapses with a motor neuron that controls the quadriceps muscle.
