Question

Обьясните механизм действия колленого рефлекса

Answer 1

Коленный рефлекс, или пателлярный рефлекс — это безусловный рефлекс, относящийся к группе рефлексов растяжения, или стретч-рефлексов. Коленный рефлекс возникает при непродолжительном растяжении четырёхглавой мышцы бедра, вызванном лёгким ударом посухожилию этой мышцы поднадколенником. При ударе сухожилие растягивается, действуя в свою очередь на мышцу-разгибатель, что вызывает непроизвольное разгибание голени. Коленный рефлекс является классическим примером моносинаптического рефлекса.

Answer 2

Mechanism of the Knee Reflex

The knee reflex, also known as the patellar reflex, is a type of stretch reflex that helps to protect the knee from potentially damaging forces. Here's a detailed explanation of its mechanism:

1. Stimulus and Sensory Receptor: - The knee reflex is initiated by a tap on the patellar tendon, which stretches the quadriceps muscle in the thigh. - The sensory receptor involved in this reflex is the muscle spindle, which is a specialized stretch receptor located within the muscle fibers of the quadriceps muscle.

2. Afferent Nerve Signal: - When the quadriceps muscle is stretched, the muscle spindle is also stretched, leading to the activation of sensory neurons called afferent neurons. - These afferent neurons carry the signal from the muscle spindle to the spinal cord.

3. Integration in the Spinal Cord: - In the spinal cord, the afferent neurons synapse with motor neurons that innervate the quadriceps muscle. - This synapse triggers a reflexive response without the need for input from the brain, making it a monosynaptic reflex.

4. Efferent Nerve Signal: - The activated motor neurons send an efferent signal back to the quadriceps muscle, causing it to contract. - This rapid contraction of the quadriceps muscle results in the extension of the leg at the knee joint, leading to the characteristic kicking motion observed in the knee reflex.

5. Function and Significance: - The knee reflex serves as a protective mechanism by quickly contracting the quadriceps muscle in response to sudden stretching, thereby preventing overextension of the knee joint and potential injury.

In summary, the knee reflex involves the rapid and involuntary contraction of the quadriceps muscle in response to a sudden stretch, providing a protective mechanism for the knee joint.

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