Digestion and Absorption

Human Digestive System

Human Digestive system includes Gastrointestinal Tract and other accessory parts like the liver, intestines, glands, mouth, stomach, gallbladder. There are 6 main functions of the Human Digestive System Process: Ingestion, Motility, Secretion, Digestion, Absorption, Excretion. The food that you eat gives you not only the required energy and nutrients to the body but also is used for cell growth and repair.

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Human Digestive System

Human-digestive-system-parts

(Source: Wikipedia)

In Human digestive system, there are many parts that work together. The food that you eat has biomacromolecules, which are nothing but the carbohydrates (such as sugars), proteins, lipids (such as fats), and nucleic acids. These have to be converted to their simpler forms so that your body can absorb it. These biomacromolecules are the building blocks that you require to maintain your body, which is also made of these large biological molecules, along with water!

This process of converting complex food substances (molecules) into simpler forms to facilitate absorption is called Digestion. In humans, this system consists of many parts and organs, including the alimentary canal, digestive glands, and a few accessory organs such as the teeth, salivary glands, tongue, pancreas, liver, gallbladder etc.

Nevertheless, the starting point where digestion actually starts in the mouth! From the mouth, it passes through the alimentary canal, which is also called the gastrointestinal tract. This tract consists of the pharynx, esophagus, stomach, small intestine, large intestine, and anus. The mouth can be considered as the anterior opening of the alimentary canal, while the anus is the posterior opening.

Digestive System Process:

From the Mouth to the Large Intestine and Anus. The Human digestive system process can be divided into stages, namely:

  • Ingestion
  • Motility
  • Secretion
  • Digestion
  • Absorption
  • Excretion

The whole process starts in the oral cavity, where the saliva from the salivary glands mixes with the food and starts to begin the breakdown of food. From the mouth, the food passes to the hollow tube-like organ the esophagus. From the esophagus, food then travels to the stomach, where it breaks down further with the help of the acids and powerful enzymes secreted by the stomach.

This semi-digested food then travels down to the small intestine, where secretions from the liver, gallbladder, and pancreas further act on the food particles.  The small intestine is divided into three parts called the duodenum, jejunum, and ileum. Most of the digestion takes place here in the small intestine, where absorption also occurs. Once most of the absorption of water and digested nutrients is completed in the small intestine, the remaining waste products move to the large intestine. The large intestine divides into appendix, caecum, colon, and rectum. The faecal matter from the large intestine comes out through the anus.

Digestive System Parts:

Mouth

The anterior opening of the alimentary canal is the mouth. It leads to a buccal cavity or oral cavity, where teeth, tongue and salivary glands are present. Here, ingestion, mastication, and swallowing of food occur. In humans, there are a total of 32 permanent teeth. There are four different types of teeth, namely, incisors, canines, premolars, and molars. These help in the chewing of food.

Human digestive system organs

(Source: Wikipedia)

Salivary Glands

They are exocrine glands that produce saliva in the oral cavity. They secrete an enzyme called amylase, which helps in the breakdown of starch into maltose. There are three types of salivary glands, namely:

  • Parotid gland
  • Submandibular gland
  • Sublingual gland

Stomach

The esophagus leads to a sac-like organ called the stomach. It is a muscular, hollow organ, having a capacity of 1 litre. The stomach holds food and also is a mixer and grinder. It secretes strong acids and powerful enzymes that help in the process of breaking down of food. Food is generally in a liquid or pastes consistency when it leaves the stomach.

human digestive system organ

(Source: Wikipedia)

Small Intestine

The small intestine is a long tube, which loosely coils in the abdomen area. Here, enzymes from the pancreas and liver further break down the food. Three segments make up the small intestines, which are the duodenum, jejunum, and ileum. The contractions of the small intestine help in the movement of food, along with its breakdown, after mixing with the digestive secretions. The jejunum and ileum areas of the small intestine are responsible for the absorption of food into the blood, though their villi.

Pancreas, Liver and Gall Bladder

These organs also play a significant role in the human digestive system. The pancreas secretes enzymes which help in the breakdown protein, fat, and carbohydrate. The liver secretes bile and cleanses and purifies the blood coming from the small intestine.  The gallbladder stores the bile that the liver produces. It releases bile into the small intestine to aid in the digestion process.

Large Intestine

The large intestine is a long muscular tube that has different parts, which are caecum, colon, and rectum. The waste that is left over after digestion of food, reaches the rectum through the peristaltic movements of the colon.

Digestive System Controls

Hormones and nerves control the human digestive system. The walls of the alimentary canal have many sensors which regulate the digestive functions. Even hormones are involved in the digestion process. The main digestive hormone, gastrin is secreted in response to the presence of food. Gastrin again stimulates the gastric acid secretion. All these regulate the digestion process.

Solved Questions For You

Q: What is digestion?

Ans. Digestion is the process of converting complex food substances (molecules) into simpler forms to facilitate absorption.

Q: What are the various organs and parts associated with the Human Digestive System?

Ans. The Digestive System in humans starts with the mouth or oral cavity, leading to the alimentary canal. The alimentary canal consists of the following – pharynx, esophagus, stomach, small intestine, large intestine, and anus. The small intestine divides into three parts namely, the duodenum, jejunum, and ileum, while the large intestine divides into an appendix, caecum, colon, and rectum. The liver, gallbladder, pancreas, teeth, salivary glands, tongue, etc. also have a role to play in the digestive system.

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Solange Annoh

Please what are the functions of a digestive system?

Araf Cuowdhury
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Araf Cuowdhury

Folsom do you know anything?

Sachin
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Sachin

Muh. Shiva gland. Stomach. Intestine liver

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