Quiz - Bowel Management Flashcards
autorhythmicity
Rhythmic smooth muscle contraction without nervous input
nervous input is required for controlled coordination
Describe the intrinsic nervous system of the GI tract.
Extends from esophagus to anus; can act independent of the nervous system.
(nervous input is required for controlled coordination)
Which two reflexes are part of the intrinsic nervous system?
Gastrocolic reflex and peristaltic reflex
What is the gastrocolic reflex?
Food or warm fluid entering the stomach causes reflexive evacuation of the colon (response is strongest after 1st meal of the day)
What is the peristaltic reflex?
Distention initiates reflexive contraction propelling food mass down
What is the role of the autonomic system?
Coordinates the bowel with the rest of the body
Which two innervation systems make up. the autonomic system?
Sympathetic and parasympathetic innervation
sympathetic innervation
Arises from T8-L2 and inhibits digestive functions
parasympathetic innervation
Cranial and sacral (S2-4) innervation that stimulates digestive functions
Somatic nervous system
Voluntary control of external anal sphincter & pelvic floor m.
Where is the somatic nervous system innervated?
S2-4
What are the two reflexes that are involved in defecation?
Intrinsic defecation reflex and the parasympathetic defecation reflex
Intrinsic defecation reflex
Mediated by the intrinsic system that when elicited by feces entering the rectum causes relaxation of the internal sphincter and increased peristalsis in the descending colon, sigmoid, and rectum
*Not usually strong enough to cause defecation
Parasympathetic defecation reflex
Required for normal defecation and is activated by a sacral spinal reflex
Once activated by filling of the rectum, it causes relaxation of the internal anal sphincter and an intensification of peristalsis in the descending colon, sigmoid, and rectum
What is the pathway for defecation
Internal anal sphincter is active at rest
–>
Feces enters the rectum and the internal sphincter relaxes
At the same time, the external anal sphincter contracts to prevent unwanted defecation (not a good time, hold it!) This contraction, caused by a sacral cord reflex, is brief.
–>
Decide whether to continue or discontinue the contraction
–>
Voluntary control is dependent on sensory input and motor output (between S2-4 and cerebral cortex)
–>
Defecation involves voluntary relaxation of the external anal sphincter and pelvic floor m., close the glottis, contract the abdominals
–>
Stimulates the defecation reflex
Bowel function after SCI
Acute SCI–> spinal shock 6-12 weeks –> areflexive bowel –> paralytic ileus
(risk for blockage, must be NPO until bowels cleared)
What is paralytic ileus?
Build up of pressure in the small intestine due to loss of peristalsis
What are the symptoms of paralytic ileus?
Absence of normal bowel sounds causing visible swelling of the abdomen and possible vomiting (can force the stomach contents up into the airways)
What are the treatment options for paralytic ileus?
Nasogastric suction, NPO status (nothing by mouth), IV fluids and electrolytes
For long-term bowl function after spinal cord injury, which of the following is/are intact: autorhythmicity, intrinsic system, autonomic system and somatic system?
Autorhythmicity and intrinsic system = YES
Somatic system = NO
Autonomic system = sometimes
Describe reflexive long-term bowel function after SCI.
S2-4 reflex arc intact, typically SCI above T12
Defecation occurs normally via reflexes
No volitional control over timing
May not fully empty
Describe areflexive long-term bowel function after SCI.
S2-4 reflex arc impaired, typically SCI below T12
Without the stronger parasympathetic defecation reflex, the bowel will not empty reflexively
High risk for feces to become impacted in the rectum
Incontinence when stool passes unhindered from the rectum
What is the key factor that determines bowel control?
The integrity of the sacral arc reflexes
GOALS FOR BOWEL MANAGEMENT
To condition the bowel to empty at scheduled intervals
Prevent constipation and impaction
Prevent AD
Minimize incontinence
