Faecal Continence: the distal part of the GI tract Flashcards
What can affect faecal continence
Medication
Natural degeneration of nerve innervation of muscle
consistency of stool (diarrhoea and constipation)
What is required to control the excretion of faeces
Holding area
Normal visceral afferent nerve fibres
Functioning muscle sphincters
Normal cerebral function
What do the rectum/ anal canal pass through
The pelvic floor
Where is the rectum located
The pelvic cavity
Where is the perineum
Inferior to the pelvic floor
What is the pelvic inlet
THe way into the pelvic cavity from the abdominal cavity
What are most of the pelvic floor muscles made up of
Levator ani
How many muscles make up the pelvic floor
3
What do the opening in the pelvic floor permit?
The distal parts of GI, Reproductive and renal tracts to pass through from the pelvic cavity into the perineum
What are the 4 parts of the distal part of the GI tract
Anus, anal canal, rectum and sigmoid colon
Where does the sigmoid colon become the rectum
anterior to S3 - the rectosigmoid junction
Where does the rectum become the anal canal
ANterior to the tip of the coccyx just prior to passing through the levator ani muscle
Where is the rectum?
In the pelvis
Where are the anal canal and the anus located
perineum
Where is the area of the rectum which dilates most?
Rectal ampulla
Where does the rectal ampulla lie?
Immediately superior to the levator ani muscle
What allows the rectal ampulla to dilate?
The relaxation of the wall
What is required to hold faeces in the ampulla until defacation
The functioning muscle and muscle sphincters
What type of muscle is the pelvic floor
Skeletal muscle
What type of response do skeletal muscles have
Voluntary
What is prolapse?
When things fall down through the muscle
What makes up the majority of the pelvic floor
The levator ani muscle and its fascial coverings
What does the levator ani muscle provide?
Continual support for the pelvic organs
What supplies the levator ani muscle
The nerve to levator ani (a branch of the sacral plexus)
Why must the levator ani muscle relax
To allow defecation and urination
What part of the levator ani muscle is particularly important for faecal continence
The puborectalis muscle
What happens when the puborectalis muscle contracts
A decrease in the anorectal angle, acting like a sphincter
What type of muscle is the puborectalis muscle
skeletal - voluntary control
What type of muscle is the interal anal sphincter
Smooth muscle
What does the internal anal spincter cover
The superior two thirds of anal canal
What stimulat the contraction of the internal anal sphincter
Sympathetic nerve
What inhibits the contraction of the internal anal sphincter
Parasympathetic nerves
In what state is the internal anal sphincter usually
Contracted
What type of muscle is the external anal sphincter
Skeletal muscle
What does the external anal sphincter cover
Inferior two thirds of the anal canal
What stimulates the contraction of the external anal sphincter?
Pudendal nerve
What happens to the external anal sphincter in reponse to rectal ampulla distension
It voluntarily contracts
What could a spinal cord injury result in
Faecal incontinence
