Organ

Movement

Digestive juices/enzymes added

Food that is broken down

Mouth Chewing Saliva Starch(Carbohydrate)

Oesophagus Peristalsis —- —-

Stomach Churning Stomach acid and Digestive Enzymes Proteins

SMALL INTESTINE Peristalsis Digestive Juices Carbohydrates, proteins, starch

Pancreas —– Pancreatic juice Carbohydrates, Fats, proteins

Liver —– Bile Fats

Large Intestine Peristalsis —- Bacteria ACT on the remaining food particles

Mechanism of Digestion

The digestion process can be divided into different stages, such as digestion in the:

ORAL cavity

Stomach

Small intestine

Large intestine

Digestion includes a complex combination of mechanical and chemical processes. Some of the activities in the process include ingestion and propulsion of food, mechanical or PHYSICAL digestion, chemical digestion, absorption, and defecation.

Digestion in the Oral Cavity

When food is taken in through the mouth, chewing and mixing of the food occurs. There is also a chemical breakdown of carbohydrates, due to the action of saliva from the salivary glands. 30% of the starch is hydrolyzed by the action of amylase, which is a salivary enzyme. The other enzyme, lysozyme is an antibacterial agent that prevents infections.

Starch + Salivary amylase → Maltose

Mastication of food and swallowing of food are the important activities that take place here in the oral cavity. Food is broken down into smaller particles by the chewing action of teeth. As saliva is added, it mixes with the food particles, slowly moistening and lubricating the food. This small ball is called a bolus, which is then swallowed. The pharynx helps in the movement of the bolus into the oesophagus, from where it moves to the stomach through the peristaltic movements of the oesophagus.