Lesson #7: Structure and Function: The Large Intestine Flashcards
(6 cards)
The Large Intestine
Undigested and unabsorbed
materials pass from the small
intestine into the large
intestine.
The large intestine is about
1.5m long
No Digestion occurs in the large
intestine.
The large intestine is divided
into 5 parts:
- Caecum (Cecum)
The first part of the large intestine
Chyme from the small intestine is passed into this entry passage of the large
intestine through the Ileocaecal Valve
The Cecum contains intestinal bacteria that breaks down (to a degree)
cellulose that is still present in the chyme
Cellulose is important for continued digestion because it is “bulk fibre” that is
used to trigger bowel movements.
- The Appendix
The small amount of cellulose that is broken down by intestinal bacteria is
stored here.
The appendix is a “vestigial” organ (has no real function)
If the appendix becomes inflamed it can rupture (appendicitis).
- The Colon
Divided into the Ascending, Transverse, Descending and Sigmoid regions.
As chyme passes through these regions of the large intestines, water is
reabsorbed into the body (this is necessary because the body uses 7L of
digestive fluid each day)
The “colons” also absorb Vitamins B and K which are produced by intestinal
bacteria
- Rectum and 5. Anus
The end of the large intestines
Feces is passed to this holding area until a “bowel movement” occurs and it
can be removed
The more “regular” or frequent the bowel movement the less time the feces
(which do contain “toxic” waste) spend in the body.
The anal sphincter is the ring of muscle that controls the “exit” of the
gastrointestinal tract.
Feces
The undigestible remains of the Chyme
Roughly 60% solid, 40% liquid
Contains Bile, Cellulose, Bacteria, water and material the body can’t break
down and use.
Too little water is reabsorbed by the intestine 🡪 “watery feces” Diarrhea
Too much water is reabsorbed by the intestine 🡪 “dry feces” Constipation
