The human alimentary canal, also known as the digestive tract, is a long, muscular tube that extends from the mouth to the anus, responsible for breaking down food and absorbing nutrients. It comprises the mouth, pharynx, esophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (colon, rectum), and anus.
Here’s a more detailed breakdown:
Mouth: This is where digestion begins with mechanical breakdown of food by teeth and mixing with saliva.
Pharynx: A passageway connecting the mouth and esophagus, also involved in swallowing.
Esophagus: A muscular tube that transports food from the pharynx to the stomach.
Stomach: A muscular organ that churns food and mixes it with digestive juices to start chemical digestion.
Small Intestine: This long, coiled tube is where most nutrient absorption occurs, with the duodenum receiving secretions from the pancreas and liver, and the jejunum and ileum absorbing nutrients into the bloodstream.
Large Intestine (Colon): This organ absorbs water and electrolytes from undigested food, forming feces.
Rectum: Stores feces until they are eliminated.
Anus: The opening through which waste is expelled.
The alimentary canal also relies on accessory organs like the pancreas, liver, and gallbladder, which contribute digestive juices and enzymes to aid in the digestive process.