9.5 Defaecation

Question 1

After the absorption of nutrients in the ileum, ____ enters the large intestine?

Answer 1

undigested food, dead cells, epithelial cells, fibre, water

Question 2

what does fibre consist of?

Answer 2

cellulose walls of plant cells

cellulose is undigestible

Question 3

Function of large intestine

Main functions of large intestine

Answer 3

• absorption of water and vitamins
• formation of faeces

Question 4

Function of large intestine

Substances absorbed by large intestine

Answer 4

• water and mineral salts
• vitamin B and K

Question 5

Function of large intestine

Describe the formation of faeces

Answer 5

• after the absorption of nutrients in the small intestine, the remaining mixture enters the large intestine.
• remaining mixture consists of water, undigested food, bacteria, dead cells and cellulose
• movement of undisgested food is facilitated by peristalsis
• absorption of mineral salts and water takes place until faeces is formed

Question 6

Defaecation

Describe the defaecation process

Answer 6

• Movement of faeces in large intestine takes about 12-24 hours before entering the rectum
• faeces accumulate in the rectumm until pressure in the rectum increases
• high pressure triggers the need to expel faeces from body
• rectum muscles contract to expel faeces from anus