Withdrawal reflex
The withdrawal reflex (nociceptive flexion reflex or flexor withdrawal reflex) is a
Example
When a person touches a hot object and withdraws their hand from it without actively thinking about it, the heat stimulates
The withdrawal reflex in the leg can be examined and measured, using an
Crossed extension reflex following withdrawal reflex
Once a danger receptor (called "nociceptor") has been stimulated, the signal travels via the sensory nerve to the dorsal (posterior) horn of the spinal cord. The nerve synapses with ipsilateral motor neurons that exit the ventral (anterior) horn of the spinal cord and work to pull the soon-to-be injured body part away from danger within 0.5 seconds.[1] At the same time, the sensory neuron synapses with the ipsilateral motor neuron, as well as the motor neuron in the contralateral anterior horn.[5] This motor neuron stabilizes the uninjured side of the body (for instance; preparing the other 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 along 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).[7]
See also
References
- ^ ISBN 0-03-011914-6.
- ^ Pearson & Gordon (2013), Cutaneous Reflexes Produce Complex Movements That Serve Protective and Postural Functions, p. 792
- ISBN 978-019-920462-5.
- ISBN 0-323-01082-2.
- ^ a b Seeley, Rod; Stephens, Trent; Philip Tate (1992). Allen, Deborah (ed.). Anatomy and physiology (2 ed.). Mosby-Year Book, Inc.
- PMID 17070999.
- ISBN 978-1-259-27772-6.
Other references
- Pearson, Keir G; Gordon, James E (2013). "35 - Spinal Reflexes". In Kandel, Eric R; Schwartz, James H; Jessell, Thomas M; Siegelbaum, Steven A; Hudspeth, AJ (eds.). Principles of Neural Science (5th ed.). United States: McGraw-Hill. ISBN 978-0-07-139011-8.