Question

Kim needs to learn about absorption of food in her digestive system, what do you tell her?

Answer 1

The digestive system is involved in the digestion and absorption of food. The digestive system contains the gastrointestinal tract and accessory digestive organs such as the tongue, salivary gland, gall bladder, liver, and pancreas.

The gastrointestinal tract consists of the mouth, esophagus, stomach, small intestine( duodenum, jejunum, and ileum) and large intestine, rectum, and anu&.

Digestion and absorption

1. Mouth- Digestion right from the mouth. With the help of saliva from the salivary gland which contains Ptyalin, it helps in breaking up of carbohydrates such as starch into smaller molecules. Here, there is digestion in small amounts but there is no absorption.

2. Stomach- The acidity of the stomach helps in breaking down the food further. It helps in chemical digestion. The main function of the stomach is digestion rather than absorption. Although some amounts of digested food can be absorbed ( in smaller amounts) eg, lipid-soluble substances and copper. It also produces intrinsic factor which later helps the small intestine in absorption.

3. Small intestine: It is the main site where absorption takes place. The small intestine is divided into duodenum, jejunum, and ileum. Duodenum mainly receives secretions from the pancreas and bile from gall bladder that mix with the food and further help in the chemical digestion of food. It also absorbs simple sugars, amino acids, and minerals. Jejunum helps in the absorption of monosaccharides, amino acids, fatty acids, vitamins, etc. The main substance that is absorbed in the ileum is vitamin B12 with the help of intrinsic factor from the stomach.

4. Large intestine: Large intestine mainly absorbs water, organic substances, and some minerals (such as NaCl).

Rectum and anu& basically receive stool from the colon and is stored there.

In this way the absorption occurs in the digestive system.