Stretch reflex of the bladder is integrated at
The bladder smooth muscle has some inherent contractile activity; however, when its nerve supply is intact, stretch receptors in the bladder wall initiate a reflex contraction that has a lower threshold than the inherent contractile response of the muscle. Fibers in the pelvic nerves are the afferent limb of the voiding reflex, and the parasympathetic fibers to the bladder that constitute the efferent limb also travel in these nerves. The reflex is integrated into the sacral portion of the spinal cord.
Sacral portion
Lumber portion
Substantia gelatinosa
Sympathetic plexus