Patellar reflex

The patellar reflex is a reflexemploying only three neurons. Striking the patellarligamentjust below the patella stretches the quadricepstendon. This stimulates sensory receptors(most importantly, muscle spindles) that trigger an impulse in a sensory neuron that leads to the lumbar region of the spinal cord. There, the sensory neuron synapses directly with a inter neuron, then to a motor neuronthat conducts the impulse to the quadriceps, triggering contraction. This coordinated with the relaxation of the antagonistic flexor hamstring muscle causes the leg to kick. It has been thought that his type of reflex helps maintain the upright posture. However, Russian scientists Gurfinkel, Lipshits and Popov showed that different control mechanisms govern human vertical posture.

See also

• Tonic vibration reflex
• Motor control

References

• Gurfinkel' VS, Lipshits MI, Popov KE (1974) Is the stretch reflex a basic mechanism in the system of regulation of human vertical posture? Biofizika. 1974 Jul-Aug;19(4):744-748.de:Patellarsehnenreflex

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It uses material from the http://en.wikipedia.org/wiki/Patellar+reflex Wikipedia article Patellar reflex.