Crossed Extension Reflex Following Withdrawal Reflex
Once a danger receptor (called 'nociceptor') has been stimulated, the signal travels via the sensory nerve to the posterior horn of the spinal cord. The nerve synapses with ipsilateral motor neurons that exit the anterior horn of the spinal cord and work to pull the injured body part away from danger within 0.5 seconds. At the same time the sensory neuron synapses with the ipsilateral motor neuron, it also synapses with the motor neuron in the contralateral anterior horn. This motor neuron stabilizes the uninjured side of the body (for instance, preparing the opposite leg to support the entire body weight when the other foot has stepped on a tack). At the same time as these two synapses, the sensory neuron also sends signals up the spinal cord to get motor neurons to contract muscles that shift the center of gravity of the body to maintain balance. This contralateral stimulation of motor neurons to stabilize the body is called the crossed extension reflex, and is a result of the withdrawal reflex (usually in the lower extremities).
Read more about this topic: Withdrawal Reflex
Famous quotes containing the words crossed, extension, reflex and/or withdrawal:
“Did you ever hear tell of Sweet Betsy from Pike.
Who crossed the wide mountains with her lover Ike,”
—Unknown. Sweet Betsey from Pike (l. 1–2)
“A dense undergrowth of extension cords sustains my upper world of lights, music, and machines of comfort.”
—Mason Cooley (b. 1927)
“No sooner does a great man depart, and leave his character as public property, than a crowd of little men rushes towards it. There they are gathered together, blinking up to it with such vision as they have, scanning it from afar, hovering round it this way and that, each cunningly endeavouring, by all arts, to catch some reflex of it in the little mirror of himself.”
—Thomas Carlyle (1795–1881)
“A bizarre sensation pervades a relationship of pretense. No truth seems true. A simple morning’s greeting and response appear loaded with innuendo and fraught with implications.... Each nicety becomes more sterile and each withdrawal more permanent.”
—Maya Angelou (b. 1928)