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:
“Like two doomed ships that pass in storm
We had crossed each other’s way:
But we made no sign, we said no word,
We had no word to say;”
—Oscar Wilde (1854–1900)
“Slavery is founded on the selfishness of man’s nature—opposition to it on his love of justice. These principles are in eternal antagonism; and when brought into collision so fiercely as slavery extension brings them, shocks and throes and convulsions must ceaselessly follow.”
—Abraham Lincoln (1809–1865)
“The theatre is the involuntary reflex of the ideas of the crowd.”
—Sarah Bernhardt (1845–1923)
“A separation situation is different for adults than it is for children. When we were very young children, a physical separation was interpreted as a violation of our inalienable rights....As we grew older, the withdrawal of love, whether that meant being misunderstood, mislabeled or slighted, became the separation situation we responded to.”
—Roger Gould (20th century)