Human Digestive System - Class 7 PDF Download

A human digestive system is a group of organs working together in converting food into energy and basic nutrients required for the body. It is made up of the gastrointestinal tract, also called as digestive tract along with liver, pancreas, and gallbladder which constitute the parts of the digestive system. The hollow organs that make up the gastrointestinal tract – GI tract include the mouth, stomach, esophagus, small intestine, large intestine that contains rectum and anus.

Some parts of nervous and circulatory systems also play a major role in the digestive process. A combination of nerves, bacteria, hormones, blood, and organs of digestive system complete the task of digestion that a person consumes in a day.

Mouth

Food starts its journey from the mouth or the oral cavity. There are many other organs that contribute to the digestion process including teeth, salivary glands, and tongue. Teeth are designed to grind food particles into small pieces and are moistened with saliva before the tongue pushes the food into the pharynx.

Pharynx

A fibromuscular y shaped tube attached to the terminal end of the mouth. It is mainly involved in the passage of chewed/crushed food from the mouth through the esophagus. It also has a major part in the respiratory system, as air travels through the pharynx from the nasal cavity on its way to the lungs.

Esophagus

This is a muscular tube that connects the pharynx which is a part of an upper section of the gastrointestinal tract. It supplies swallowed food along with its length.

Stomach

It serves as a muscular bag which is situated towards the left side of the abdominal cavity, beneath the diaphragm. This vital organ acts as a storage for the food and provides enough time to digest meals. The stomach also produces digestive enzymes and hydrochloric acid that maintains the process of digestion.

Pancreas

It is a larger gland present just inferior to the stomach. It is short with its head connected to the duodenum and tail pointing towards the left part of the abdominal cavity. The pancreas releases digestive enzymes to complete the process of chemical digestion.

Small Intestine

A  thin, long tube of about 10 feet long and a part of the lower gastrointestinal tract. It is present just behind the stomach and acquires a maximum area of the abdominal cavity. The complete small intestine is coiled and inner surface consists of folds and ridges.

Large Intestine

This is a thick, long tube measuring around 5 feet in length. It is present just beneath to the stomach and wraps over the superior and lateral edges of the small intestine. It absorbs water and consists of bacteria (symbiotic) that support in the break down of wastes to fetch small nutrients.

Waste products are passed through the large intestine and eliminated out of the body as a solid matter called stool.

Importance of digestion

Digestion is necessary for breaking down food particles into nutrients that are used by the body as a source energy, cell repair, and growth. Food and drink need to be converted into smaller molecules of nutrients before absorbed by the blood and carried to the cells throughout the body. The body breaks the nutrients from the drink and food into carbohydrates, vitamins, fats, and proteins.