Describe the alimentary canal of man.
The human alimentary canal has following parts:
Buccal Cavity: Buccal cavity contains tongue, teeth and salivary glands. Food enters the digestive system through buccal cavity.
Oesophagus: Buccal cavity is connected to a long tube-like structure; called oesophagus. Oesophagus has a valve to prevent the backflow of food into mouth.
Stomach: Stomach is a J-shaped organ. The buccal cavity opens into the stomach. Walls of stomach are composed of muscles. Gastric glands are present in the stomach. These glands secrete hydrochloric acid, pepsin and mucus.
Small Intestine: This is long and highly coiled structure. The lumen of the small intestine is smaller than that of large intestine. The stomach opens into small intestine. The hepatopancreatic duct opens into the small intestine. Villi are present in small intestine to facilitate absorption of food.
Large Intestine: This is shorter than small intestine. The lumen of large intestine is larger than that of small intestine.
Rectum: Large intestine opens into rectum. Waste materials and undigested food are stored in rectum.
