Question

What are the main parts of the alimentary canal?

Answer 1

Hint: We engulf food from the mouth in solid form. This food then passes through a canal known as the alimentary canal. Through this the food reaches the stomach where it is broken down into finer particles and used as a source of energy. Digestive enzymes and the acid present in the stomach breaks it into finer particles so that energy can be obtained out of the ingested food.

Complete answer:
The alimentary canal begins from the mouth and ends at the anus. The basic function of the alimentary canal is to break down food into finer particles and make it absorbable. The alimentary canal also helps in the removal of unutilized part of the food.
The first organ of the alimentary canal is the mouth. It contains teeth, tongue, salivary glands, etc. As soon as food enters the mouth, it is broken down into finer pieces with the help of teeth and is mixed with the saliva. The tongue pushes the food further towards the esophagus.
Esophagus, also known as the food pipe, is located near the trachea. A muscular flap called the epiglottis covers the trachea to prevent entry of food inside. Food travels down the esophagus through peristalsis.
After peristaltic movement of the esophagus, food reaches the stomach which is a muscular bag like organ. It contains cells that secrete acid and certain enzymes that help in the breakdown of food. When the food particles are sufficiently broken down, the food enters into the small intestine.
Small intestine consists of three parts namely, the jejunum, the duodenum and the ileum. Here, food is broken down with the help of bile from the liver and enzymes from the pancreas. The main function of the duodenum is breaking down of food whereas jejunum and ileum mainly help in the absorption of nutrients from the ingested food. The content leaves the small intestine in the form of liquid.
After the small intestine, food enters the large intestine which is also known as the colon. The main function of the large intestine here is reabsorption of water so that waste material that enters in liquid form leaves the large intestine in solid form.
After a large intestine, food reaches the rectum where it is stored till it is excreted out. The rectum sends signals to the brain about the release of fecal matter.
The last part of the alimentary canal is the anus. The anal sphincters are responsible for holding our stool and preventing the involuntary removal of still from the body.

Note:
 The process of digestion of food begins in the mouth itself, where the salivary amylase starts breaking down carbohydrates. There are no digestive enzymes in the esophagus. Apart from the organs of the alimentary canal, there is gallbladder, liver and the pancreas that help the alimentary canal to carry out the process of digestion.