Large Intestine Flashcards
(25 cards)
What is the approximate length of the large intestine?
About 1.5 m long.
Does the large intestine contain villi?
No.
What does the large intestine secrete?
Mucous.
What are the main functions of the large intestine?
Absorption of water, salts, and vitamins.
What happens to the contents of the large intestine as a result of absorption?
The contents become more solid.
What role do bacteria in the large intestine play?
Digest cellulose in plant foods and synthesize some vitamins.
What is faeces?
The semi-solid material in the large intestine after water absorption and bacterial action are completed.
What components typically make up faeces?
- Undigested food material (particularly cellulose)
- Bacteria
- Bile pigments
- Discarded lining cells
- Water
What is defaecation?
The elimination of undigested wastes from the large intestine.
What is cellulose?
An insoluble polysaccharide (carbohydrate).
Can humans break down cellulose?
No, humans lack the enzyme required.
What happens to ingested cellulose (fibre) in the digestive tract?
It is eliminated.
How does cellulose (fibre) affect the smooth muscle walls of the intestine?
It stretches the walls, causing reflexive contractions that move material along.
What is the effect of diets low in cellulose (fibre)?
Intestinal contents move more slowly through the digestive tract.
What can drier intestinal contents lead to?
Difficult movement through the tract.
What is constipation?
Delayed, difficult, or irregular defaecation.
What dietary factors can contribute to constipation?
A lack of fibre and water.
What dietary changes can help prevent or cure constipation?
Increased fibre and water.
What can constipation lead to in terms of bowel disease?
The development of haemorrhoids.
What causes haemorrhoids?
Straining that causes the protrusion or rupture of blood vessels in the rectum or anus.
What is diarrhoea?
The frequent elimination of watery faeces.
What can cause diarrhoea?
Foods, bacteria, or viruses.
What happens to the rate of peristalsis during diarrhoea?
It increases, leading to inadequate time for water resorption.
What is a risk factor for bowel cancer?
Diets with less fruit and vegetables (and more refined/fatty diets).
