Explain the internal structure of the gut.

Explanation

The wall of the alimentary canal from oesophagus to rectum consists of four layers (Figure) namely serosa, muscularis, sub-mucosa and mucus. The serusa (visceral peritoneum) is the outermost layer and is made up of thin squamous Submucosa epithelium with some connective tissues. Musculars Muscularis is made of smooth circular and longitudinal muscle fibres with a network of nerve cells and parasympathetic Circular Longitudinales nerve fibres which controls peristalsis. The submucosal layer is formed of loose connective tissue containing nerves, blood, lymph vessels and the sympathetic nerve fibres that control the secretions of intestinal juice. The innermost layer lining the lumen of the alimentary canal is the mucosa which secretes mucous.