The last stretch

The idea

Unabsorbed food passes into the large intestine, whose wall absorbs more water; the remaining waste leaves through the anus, its exit regulated by the anal sphincter.

What is left

After digestion and absorption in the small intestine, some food material is left over.

What do you think happens to it next?

• It goes to the large intestine
• It goes back to the mouth
• It goes to the stomach again

Follow the waste

Open each tab.

Water back to the body

The material that the small intestine did not absorb moves into the large intestine. The wall of the large intestine absorbs more water from it. What remains is waste, and it leaves the body through the anus. A muscle, the anal sphincter, regulates when it leaves.

Unabsorbed food passes into the large intestine, whose wall absorbs more water; the remaining waste leaves through the anus, its exit regulated by the anal sphincter.

Notes

Unabsorbed food enters the large intestine, whose wall absorbs more water; the rest leaves through the anus, regulated by the anal sphincter.

Check yourself

What does the wall of the large intestine absorb from the unabsorbed food?

What regulates the exit of waste material from the body?

Through which opening does the remaining waste leave the alimentary canal?

• More water — correct. Yes!
• Amino acids. The digested food is taken up by the walls of the small intestine, through the villi.
• Bile. Bile is made by the liver and acts in the small intestine.
• The sphincter at the exit of the stomach. That sphincter regulates the exit of food from the stomach into the small intestine.
• The anal sphincter — correct. Yes!
• The villi. Villi absorb digested food in the small intestine; they do not regulate the exit of waste.
• The urethra. The urethra is the tube through which urine is passed out.
• The food-pipe. The food-pipe takes food from the mouth to the stomach.
• The anus — correct. Yes!