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The stretch reflex (myotatic reflex), or more accurately "muscle stretch reflex", is a muscle contraction in response to stretching a muscle. The function of the reflex is generally thought to be maintaining the muscle at a constant length but the response is often coordinated across multiple muscles and even joints. [ 1 ]
The Bainbridge reflex is the predominant, [16] [17] but not the only mechanism mediating increases in heart rate in response to increased atrial stretch: stretching of the pacemaker cells of the sinoatrial node has a direct positive chronotropic effect on the rate of the sinoatrial node. [18]
The patellar reflex, also called the knee reflex or knee-jerk, is a stretch reflex which tests the L2, L3, and L4 segments of the spinal cord. Many animals, most significantly humans, have been seen to have the patellar reflex, including dogs, cats, horses, and other mammalian species.
Stretch reflex tests are used to determine the integrity of the spinal cord and peripheral nervous system, and they can be used to determine the presence of a neuromuscular disease. [4] The term "deep tendon reflex", if it refers to the muscle stretch reflex, is a misnomer. "Tendons have little to do with the response, other than being ...
The stretch reflex operates as a feedback mechanism to control muscle length by causing muscle contraction. In contrast, the tendon reflex operates as a negative feedback mechanism to control muscle tension. Although the tendon reflex is less sensitive than the stretch reflex, it can override the stretch reflex when tension is great, for ...
Joints are controlled by two opposing sets of muscles called extensors and flexors, that work in synchrony for smooth movement.When a muscle spindle is stretched, the stretch reflex is activated, and the opposing muscle group must be inhibited to prevent it from working against the contraction of the homonymous muscle.
A stretch reflex is the contraction of a muscle in response to its lengthwise stretch. Biceps reflex (C5, C6) Brachioradialis reflex (C5, C6, C7) Extensor digitorum reflex (C6, C7) Triceps reflex (C6, C7, C8) Patellar reflex or knee-jerk reflex (L2, L3, L4) Ankle jerk reflex (Achilles reflex) (S1, S2)
The knee jerk is the popularly known stretch reflex (involuntary kick of the lower leg) induced by tapping the knee with a rubber-headed hammer. The hammer strikes a tendon that inserts an extensor muscle in the front of the thigh into the lower leg.