Question

Which of the following is the correct sequence of parts in human alimentary canal?

• A. Mouth $\to$ Stomach $\to$ Small intestine $\to$ Oesophagus $\to$ Large intestine
• B. Mouth $\to$ Oesophagus $\to$ Stomach $\to$ Large intestine $\to$ Small intestine
• C. Mouth $\to$ Stomach $\to$ Oesophagus $\to$ Small intestine $\to$ Large intestine
• D. Mouth $\to$ Oesophagus $\to$ Stomach $\to$ Small intestine$\to$ Large intestine

Answer 1

The correct option is D Mouth $\to$ Oesophagus $\to$ Stomach $\to$ Small intestine$\to$ Large intestine

Hint - The digestion of food starts from the mouth and ends at the anus.

Part 1 - Alimentary canal

• The alimentary canal is a hollow muscular tube organ that starts at the mouth and terminates at the anus.
• The function of the alimentary canal is digestion and absorption of the food.
• The important parts of the alimentary canal are – Mouth, Oesophagus, Stomach, Small intestine and Large intestine.

Part 2 - Parts of the Alimentary canal

The different organs of the alimentary canal can be explained as –

• Mouthis the first part of the alimentary canal where partial digestion of food takes place with the help of saliva secreted by the salivary gland. From the mouth, food enters the Oesophagus.
• Oesophagus is a long and thin muscular tube that passes through the neck, thorax and diaphragm and opens into a muscular bag-like structure called the stomach.
• Stomach is a muscular organ consist of three regions – cardiac region, fundic region and pyloric region. The pyloric region of the stomach opens into the ‘C’ shaped duodenum of the small intestine.
• Small Intestine - The longest part of the alimentary canal is divided into three parts- Duodenum, Jejunum, and Ileum. The ileum opens into the large intestine.
• Large Intestine - It is a wide tube consists of three parts- Caecum, Colon, and Rectum. The colon is divided into four regions- ascending colon, the transverse colon, descending colon and the sigmoid colon. Through the sigmoid colon the descending part of the colon opens into Rectum. The rectum is the distal part of the alimentary canal that opens into the anus.

Part 3 - Conclusion

• Food enters the body through the mouth. Then enters the stomach through the oesophagus. From the stomach, the semi-digested food enters into the small intestine where digestion and absorption take place. At last, the food travels through the large intestine and excess water get absorbed.

Final stage - The correct sequence of the human alimentary canal is Mouth $\to$ Oesophagus $\to$ Stomach $\to$ Small intestine $\to$ Large intestine.