The Large Intestine
(or colon(whichever you prefer))
By Denham
The Large Intestine
(Also known as the colon)
Large Intestine
The large intestine is the last part of the
digestion process before excretion. It is about
1.5 meters long and reaches from the end of the small intestine to the anus. Food moves along in here at about 4.7 centimeters an hour and takes 32 hours to complete the process. The food
Structure
The large intestine does not have any villi covering it, but it does have a lot of goblet cells as well as similar tissues to those found in the other parts of the digestive tract. There is a muscle layer which runs along the colon, and it makes haustra.
pH Level
The large intestine has a pH level of between
Main parts
The main parts of the large intestine are the cecum, the ascending colon, the transverse
colon, the descending colon, the sigmoid colon, and the rectum.
Process
When the food initially enters the large
intestine, it has already been broken down and is now nearly ready for excretion. However
there is too much water in the food for it to be excreted properly, so the large intestine must
absord this water and recycle it for other uses in the body. The food moves along by muscle
Cecum
The food enters the cecum after travelling
through the small intestine. The food cannot
return to the small intestine due to the ileocecal valve which partitions and prevents the food
Ascending, Transverse, and Descending Colon
These three parts are the middle of the large
Sigmoid
Rectum
Bacteria
The large intestine contains around 700 bacteria, such as Esterichia Coli, but these
bacteria are essential to the digestion process: -They make vitamin K (Used in stopping the flow of blood when you cut yourself)
-Helps break down carbohydrates your enzymes can’t break down, such as cellulose
Products of Bacteria
Problems
Constipation
Constipation occurs when your food moves through your large intestine too slowly. As your food moves, water is being absorbed by osmosis. Since your stool is moving so slowly, water is continuously being
absrbed from your stool. This cause it to dry out and become hard, which doesn’t allow it to move as
Some lifestyle habits that may cause constipation include
• changing your normal diet, exercise, or travel habits • ignoring the urge to have a bowel movement
• feeling a lot of stress
• eating a low-fiber diet
• not drinking enough liquids
• taking calcium or iron supplements
• taking medicines such as painkillers with codeine; diuretics, also known as water pills; medicine for depression; and some antacids
Some medical conditions that may cause constipation include
• pregnancy or having given birth
• problems with the muscles and nerves in the intestine, rectum, or anus
• irritable bowel syndrome, a condition in which the nerves that control the muscles in the intestine don't function correctly; the intestine becomes sensitive to food, stool, gas, and stress
• diabetes, a condition in which a person has high blood sugar, also called
hyperglycemia, because the body cannot use blood glucose, or blood sugar, for energy
Other Problems Associated With the L.I.
Colorectal Cancer Cancer that rises from the lining of the large intestine.
Constipation Bowel movements that occur less then three times a week. Stools are hard, dry and move in small amounts.
Diarrhea Frequent watery, loose stools.
Gardner’s Syndrome Multiple polyps that appear along the colon or other parts of the GI tract. Inflammatory Bowel Di
sease (IBD) Inflammatory bowel disease (IBD) is the umbrella that covers Crohn’s disease and ulcerative colitis. Irritable Bowel Syndro
me Motility disorder of the large and small intestine, without evidence of anatomical abnormality or organic illness. Ischemic Colitis An acute vascular insufficiency of the colon.
Necrotizing Enterocoliti
s A disease of focal or diffuse ulceration of the GI tract that usually occurs in the distal small bowel and/or colon. Peutz-Jeghers Syndrom
e Characterized by mucocutaneous pigmentation on the face, hands and feet and in the perianal and genital areas. Polyp A growth that protrudes into the lumen of the bowel. There are two types of
polyps: hyperplastic and adenomas. Pseudomebranous
Colitis An acute inflammation of the bowel, resulting from antibiotic therapy. Radiation Enteritis Alterations in epithelial cell function.
Ulcerative Colitis A chronic, recurrent inflammation that affects the lining of the large intestine.
A Short Video…
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Questions
How long does it take for the food to travel through the large intestine?
What are all the parts of the LI? In order?
What was the example of a carb the bacteria in the LI helps break down?
What are the pouches that move the food along called?
ANSWERS!!!!!!!!!!!!
1. 32 hours
2. Cecum, ascending colon, transverse colon, descending colon, sigmoid colon, rectum. 3. Cellulose
4. Haustra
5. Food moves too slow through the LI and water is continuously being absorbed. This makes the
