give a brief note on alimentary canal
Gut or alimentary canal is a long, coiled, muscular tube extending from mouth to anus through which food passes after it is eaten. It consists of mouth leading into buccal cavity, pharynx, oesophagus, stomach, small intestine, large intestine and anus. The lumen or cavity of alimentary canal is surrounded by wall made up of four layers of different types of cells: mucosa, submucosa, muscularis externa and serosa. Alimentary canal is meant for digestion, absorption and expelling of undigested wastes.