**Digestion** is a process in which an organism obtains nutrients and energy through the breakdown of the food we intake. This process happens in our digestive system and comprises the following organs: mouth, pharynx, esophagus, stomach, small intestine, and large intestine.

**Organs of the digestive system**

1. Mouth – this organ functions to mechanically break down the food we eat. It converts food materials into a simple form.
2. Esophagus – this organ performs the process of *peristalsis*. In which the food material is being moved from the mouth to the stomach through a muscle contraction.
3. Stomach – breaks down food materials in a mechanical and chemical manner.
4. Small intestine – Where most of the chemical digestion and absorption of nutrients happens.
5. Large intestine – where reabsorption of water happens. Water is absorbed efficiently and quickly in this organ.

The digestive system works in breaking down the food into smaller or simpler components that the body can absorb and use in order to perform cellular processes.

Both mechanical digestion and chemical digestion are involved in the digestive process of the body. Mechanical digestion refers to the process of grinding and crushing the food by chewing. Large pieces of food are broken down physically into smaller pieces. While chewing, chemical digestion also occurs. This refers to the process of breaking down the food particles into smaller components using the digestive enzymes in the body.

**Liver** is the accessory organ that supports the whole gastrointestinal tract in lipid digestion. This organ is located just superior to the stomach and it is the largest accessory organ of the digestive system.

The liver functions to produce the fluid called **bile**. This fluid plays an important role in the digestion and transport of fat molecules found in our food. Through the aid of bile, enzymes can easily break down these fat molecules for the cells to absorb.

The **small intestine** is the portion of the gastrointestinal tract which plays an important role in the absorption of nutrients. The folded epithelial surface of this tract is covered with fingerlike projections called **villi** which provide a large surface area for the absorption of nutrients.

As nutrient molecules are being absorbed into the walls of the small intestine, water, and cellulose pass by a small sac-like projection called **appendix** before it enters the large intestine. This organ is considered vestigial in humans but in other animals, this organ is used to store cellulose and other materials. Therefore, when you observed an animal having a large appendix, it is more likely that this animal is an herbivore.