Fleksiyonrefleksi

Fleksiyonrefleksi, also known as the withdrawal reflex, is a basic spinal reflex. It is a polysynaptic reflex that causes flexion of the limbs to withdraw from a painful stimulus. This reflex is crucial for protecting the body from injury.

When a noxious stimulus, such as touching a hot object, is detected by nociceptors (pain receptors) in the skin, a signal is sent via sensory neurons to the spinal cord. In the spinal cord, the sensory neuron synapses with one or more interneurons. These interneurons then synapse with motor neurons.

The motor neurons transmit signals to the flexor muscles in the limb. These muscles contract, causing the limb to flex and withdraw from the painful stimulus. Simultaneously, the flexor reflex also leads to the relaxation of the extensor muscles in the same limb, further facilitating the withdrawal.

An important characteristic of the flexor reflex is its crossed extensor component. While the ipsilateral limb withdraws, the contralateral limb extends. This extension helps to support the body's weight and maintain balance during the withdrawal. For example, if you step on something sharp with your right foot, your right leg will flex to lift your foot, while your left leg will extend to support your body.

The flexor reflex is a rapid and involuntary response, meaning it occurs without conscious thought. This speed is essential for minimizing tissue damage. The entire pathway, from stimulus detection to muscle contraction, is known as the reflex arc.