diarrhoea Flashcards
what is defecation?
Defecation is the term given for the act of expelling faces from the digestive tract via the anus.
what systems does defecation involve?
GI system
nervous system
musculoskeletal system
what happens in defecation?
- expel undigested portions of food
- expel metabolic waste from the body in the form of stool
- stools containing bacteria and cellular debris from GIT
how frequent is defecation?
- varies on age and diet
usual normal bowel:1-3 times a day
what role does the colon have in defecation?
right- mixes and stores contents
left- conduit
what does rectum and anal canal do in defecation?
it enables defecation and maintains faecal continence
what is the colon responsible for?
- delay passage of luminal contents to allow for water absorption
- allow for segmentation and mixing luminal contents with the mucosa
- store faecal matter before defecation
- propel faeces towards the rectum
- begins the urge to defecate
what controls the act of defecation?
two sphincters
internal anal sphincter- smooth muscle cells- involuntary control
external anal sphincter- striated muscle cells- voluntary control
what is the mechanism of defecation?
the pudendal nevre provides the voluntary motor control of faecal and urinary continence
- the pelvic nerve regulate the emptying of the urinary bladder
- the hypogastric nerve is responsible for proprioception and proper functioning or the urethral and anal sphincters
what is the pre-defecatory phase?
1 hour before actual defecation
majority of the colon exhibits an increase in propulsive peristalsis waves
-colonic mass improvements and peristalsis move intentional contents distally into the rectum
- sensation to poo is not evident till 15 min before hand
what happens when stools reaches the rectum?
There is activation of recto-anal inhibitor reflex
process of determining if the rectal contents are of the gas solid or liquid
what happens when stool comes in contact with the receptors in the upper anal canal?
this can affect relaxation of the inner anal sphincter
what happens if the external anal sphincter does not relax?
- retrograde passage of stool into the rectum
- diminished proximal peristaltic propagative waves
- maintained continence when immediate defecation is not desirable or convenient
what do you do when you are revaluating the rectum and defecation?
-squatting position
-contraction of the abdominal musculature of the diaphragm
relaxed pelvic floor facilities defecation
what is the process of expulsion of feces?
- contraction of the abdominal muscles
- performing the valsalva manoeuvre
- relaxing the external anal sphincter and puborectalis muscle
what happens after faecal expulsion?
the external anal sphincter regains its tone to maintain continence at rest
what does the size and the consistency of the stool as well as bacterial content vary with?
- vary based on diet and water intake
- determined by transit time
what would changes in defecation habits be a sign of?
- common symptom of the defecation process
- is a common side effects to many therapies
- may indicate alarming condition such as colorectal malignancy
what would stool form alteration be indicative of?
disease:
-steatorrhea results from lack of adequate amounts of pancreatic enzymes and/or bile acids and intestinal malabsorption
how can a stool content provide diagnostic information?
e.g. c. difficle : watery diarrhea, fever, nausea and abdominal pain
what are the 3 pathophysiology associated with defecation?
diarrhea
constipation
faecal incontienence
what is diarrhoea?
it is defined as an increase passage of loose or watery stools relative to usual habit
it is not a disease
what is the usual cause of diarrhoea?
usually caused by a viral or bacterial infection
also associated with other conditions such as IBS/IBD
What are the subcategories of diarrhoea?
osmotic, secretory, inflammatory, functional