The parasympathetic nervous system is referred to as the craniosacral outflow; the pelvic splanchnic nerves are the sacral component.
[2] The nerves regulate the emptying of the urinary bladder, control opening and closing of the internal urethral sphincter, influence motility in the rectum as well as sexual functions like erection.
[1][2] In the distal 1/3 of the transverse colon, and through the sigmoid and rectum, and the cervix in females, the pelvic splanchnic nerves supply parasympathetic function, including transmitting the sensation of pain.
Damage to the sacral spinal nerve roots can cause neurogenic bladder dysfunction[2] and fecal incontinence.
[3] The pelvic splanchnic nerves are featured as a key plot point in "Parasites Lost", a 2001 episode of the American animated TV comedy Futurama; when protagonist Philip J. Fry is infected with parasitic worms, the rest of the crew use micro-droids to enter his body with the intention of tickling the pelvic splanchnic ganglion to trigger a convulsive bowel movement that they believe will expel the worms.