The human alimentary canal has following main parts:

Mouth: Alimentary canal starts from the mouth and ends in the anus. Mouth opens into a chamber or cavity called buccal cavity. The buccal cavity contains teeth, tongue and salivary glands. The teeth cut the food into small pieces, chew and grind it.

Oesophagus: Buccal cavity opens into pharynx which leads to a long tube called Oesophagus. Oesophagus is also known as food pipe. The walls of Oesophagus are highly muscular. Digestion does not occur in the Oesophagus. It carries the food down into the stomach.

Stomach: Stomach is a bag-like organ. Highly muscular walls of the stomach help in churning the food.

Small Intestine: It is a highly coiled tube-like structure. The small intestine is longer than the large intestine but its lumen is smaller than that of the large intestine. The small intestine is divided into three parts, viz. duodenum, jejunum and ileum. In humans, small intestine is the site of complete digestion of food like carbohydrates, proteins and fats.

Large Intestine: Undigested food goes into the large intestine. Anus is the opening at the end of the alimentary canal through which undigested food is thrown out.