Chapter 24, Problem 1CP

Which components of the digestive system are GI tract organs, and which are accessory digestive organs?

Summary Introduction

To review:

The gastrointestinal (GI) tract organs as well as accessory digestive organs.

Introduction:

Digestion is the process, by which the larger food particles are broken down into smaller absorbable molecules. This system consists of GI tract (alimentary canal) and the accessory organs.

Explanation of Solution

The digestive system is divided into two major subdivisions:

GI tract

Accessory organs

The organs of the alimentary canal are pharynx, mouth, stomach, esophagus, and small as well as large intestines. The GI tract is a long tube-like structure that spans from the mouth up to the anus. The accessory digestive organs include the salivary glands, teeth, gallbladder, tongue, pancreas, and liver. The functions of different digestive system's organs are described below:

The mouth is the opening of the alimentary canal. Food enters the digestive tract via the mouth. Mouth consists of the salivary glands, teeth, and the tongue. Salivary glands secrete saliva that helps in the digestion of carbohydrates. Teeth and tongue help in the mastication of food. Then the food goes into the esophagus, through which the food enters the stomach. Peristaltic movements (rhythmic contractions and relaxations) in the esophagus enable food to move into the stomach.

The stomach is a muscular bag, which is involved in the hydrolysis of protein. It releases pepsin for protein digestion and also secretes hydrochloric acid to make the food acidic so that the intestinal enzymes can act on it.

The small intestine is where the digestion ends. It has three subdivisions namely, duodenum followed by jejunum and lastly the ileum. It receives secretions from the liver and the pancreas that digest the food further. This is where the food components are absorbed via the villi in the small intestine.

The large intestine is usually involved in the absorption of water and nutrients by the body. The subdivisions of the large intestine are rectum, cecum, colon, anal canal, and appendix. Other digestive organs include pancreas, gallbladder, and liver.

Conclusion

Thus, the different digestive organs include organs of the alimentary canal and the accessory organs. These organs work together to break down the large food particles into smaller absorbable molecules. These molecules are then absorbed in the blood and thus, the energy and nutrition are supplied to different body tissues.