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Body Systems

Digestion: From the mouth to the stomach

Digestion: The intestines

Biology
The Human Body
Body Systems

Digestion: The intestines

Digestion: The intestines

Where does the last part of digestion take place?

Protein

A nutrient found in food that is made up of smaller parts called amino acids. It is a necessary part of the diet and keeps cells healthy and functioning normally. Also assists in building muscle tissue.

Enzyme

A kind of protein that speeds up or slows down chemical reactions in our digestive system.

Duodenum

The part of the small intestine that is right below the stomach.

Amino acid

The building blocks of proteins. There are twenty different kinds of amino acids that the human body needs, nine of which the body cannot produce by itself.

Mineral

An essential elementary substance, which is not made by plants or animals, that is needed by humans, plants and animals in order to remain healthy and develop normally.

Vitamin

An essential organic compound that we get from our food that helps the body to remain healthy and develop normally.

Carbohydrate

A substance, such as starch or sugar, that is rich in energy and is made up of carbon, hydrogen and oxygen and is an important part of human diets.

Glucose

A simple sugar that can be quickly broken down into energy in an organism. It is found naturally in plants.

Mucus

A thick, slimy substance that protects things from drying out. Found in the nose, lungs and intestines.

Digestion

A process in which the body breaks down and absorbs important substances from food.

Pancreas

A large gland located behind the stomach that produces insulin to regulate the glucose level in the blood. It also secretes pancreatic fluid into the intestine, which is needed to break down food.

Bile

A substance produced in the liver, and stored in the gallbladder, which breaks down fat into small droplets during digestion.

Gallbladder

An organ located next to the liver that stores the bile produced by the liver.

Intestinal villi

Finger-like structures on the inside of the small intestine that absorb nutrients from food.

Colon

The main part of the large intestine where excess water is absorbed from food passing through and feces are formed. It also contains a large amount of bacteria that help to free vitamins from the food so that the body can absorb the vitamins.

Gastrointestinal tract

A system of organs, glands and vessels that assists with taking in food, breaking it down, absorbing energy and nutrients from the food, and getting rid of the remaining waste in the form of feces and urine.

Rectum

The end part of the gastrointestinal tract, where feces are stored.

Small intestine

A long, curving tube that connects the stomach to the large intestine.

A number between 0 and 14 that indicates how acidic or basic a chemical is.

Where were we? Yes, that's right! The food had been digested in the stomach... On we go to step four - the duodenum! Small portions of the food pass from the stomach to the duodenum.

Since it's so acidic, the food has to be neutralized before it can go on. This happens here, with the help of juice from the pancreas. Pancreatic juice has a pH of about eight and a half and it also contains several different enzymes that continue the digestion of carbohydrates and proteins. A substance called bile also enters the duodenum from the gallbladder. Bile works like washing-up liquid - it breaks down the fat - the lipids - into smaller droplets.

From the duodenum we proceed to step five - the small intestine. The food is now a light fluid. Here there's an intestinal juice which also contains enzymes, and in the small intestine the last digestion takes place. The carbohydrates have been broken down into glucose, and the proteins have been converted to amino acids. These molecules are small enough to pass through the intestinal wall into the blood.

Some vitamins and minerals are also absorbed by the body from the small intestine. For this absorption to work as efficiently as possible, the intestinal wall is folded, and on these folds there are tiny flaps called intestinal villi. With the folds and the villi, the total area of the small intestine is close to thirty square meters! Now we have reached step 6 - the colon. To avoid losing too much water with the feces, water is drawn from the contents of the intestines into the body.

In the colon there are lots of bacteria, about 200 grams. Among other things they help to free vitamins from the intestinal contents. Some bacteria leave the body together with the poo. About half of our feces consists of bacteria, both living and dead. If the intestinal bacteria change or are harmed, that is, if too many of them die, we become very ill.

In the intestinal wall there are cells producing mucus that lubricates the feces, so it can exit the body more easily. And now we have reached the last step of the Gastro-Intestinal Tract: step seven - the rectum. In due course this is filled with matter from the colon, and when it's full we get an urgent feeling, just like Maria did. Then it's important that we go and poo, otherwise the body becomes unwell.