Answer:
Mouth
The mouth is the first part of our digestive system. Food is ingested through the mouth.
Oral cavity
The oral cavity comprises the palate, tongue and teeth.
Palate – The roof of the oral cavity.
Tongue – Muscular and glandular structure attached to the base of the oral cavity. The upper surface of the tongue has tiny projections known as lingual papillae. Lingual papillae are of three types: circumvallate, fungiform and filiform.
Pharynx
It is the common passage for food and air. Epiglottis prevents the entry of food into the windpipe.
Oesophagus
It is a muscular tube through which small bolus of food passes from the mouth to the stomach. The gastro-oesophageal sphincter controls the movement of food into the stomach.
Stomach
It is a muscular bag, positioned at the upper left part of the abdominal cavity. It has four parts- cardiac, fundus, body and pyloric portion.
Cardiac part– It is present close to the heart. The opening of the oesophagus to the stomach is regulated by the gastro-oesophageal sphincter.
Fundus– It is dome-shaped and is usually filled with air.
Body– This is the main part of the stomach.
Pyloric- It opens in the first part of the small intestine, duodenum. The opening of the stomach into the small intestine is regulated by the pyloric sphincter.
Small Intestine
It is the longest part of the alimentary canal and comprises three parts- Duodenum, Jejunum, and Ileum.
Duodenum– It is C- shaped. The pancreatic, bile and hepatic secretions are added to the food by hepatopancreatic duct.
Jejunum– Middle part of the small intestine.
Ileum– It is highly coiled and opens into the large intestine.
Large Intestine
The small intestine leads into the large intestine. It has three parts- Caecum, Colon, and Rectum.
Caecum– It is a small sac-like structure containing symbiotic microorganisms. The vermiform appendix (vestigial organ) is attached to it.
Colon– It is divided into four regions- ascending, transverse, sigmoid and descending.
Rectum– It opens into the anus.
Explanation:
