Parts of the digestive system The digestive system and what each part does 2.5 / 5 based on 2 ratings ? BiologyHuman, animal and plant physiologyAS Created by: Marianne BradleyCreated on: 03-10-10 13:12 Buccal cavity Teeth. Canines rip/tear, incisors bite and molars chew. Salivary amylase: hydrolyses starch to maltose. Buffers: neutralise acid. Mucoproteins: lubricate 1 of 14 Epiglottis Protects the larynx during swallowing CLoses over the trachea to prevent choking 2 of 14 Oesophagus Circular muscles squeeze food down to the cardiac sphincter using peristalsis. 3 of 14 Stomach Highly elasticated muscular organ Wall:highly folded and dotted with gastric pits. Food churned into CHYME Mucus comes from goblet cells HCl comes from oxyntic cells Pepsinogen comes from chief cells. It hydrolyses polypeptides into smaller polypeptides. 4 of 14 Duodenum First part of small intestine. Pyloric sphincter controls exit of the stomach. Almost all digestion occurs here. No villi Where pancreatic juices are used. Exopeptidases: hydrolyse peptide bonds at end of polypeptides. 5 of 14 Pancreas Large gland situated below the stomach. Produces pancreatic juice. pancreatic amylase: digests starch into maltose pancreatic endopeptidases: digest proteins into short peptides Pancreatic lipase: digest triglycerides to fatty acids and glycerol Pancreatic nucleases: hydrolyse DNA and RNA to nucleotides 6 of 14 Liver Secretes bile, which aids with digestion 7 of 14 Gall bladder Stores bile and BILE SALTS Helps lipid digestion by emulsifying them Neutralises stomach acid 8 of 14 Jejunum 2m long Large folding of mucosa, then villi, then microvilli 9 of 14 Ileum 4m long Final site of digestion and absorption Numerous glands in the mucosa and submucosa secrete enzymes, mucus and NaHCO3 10 of 14 Appendix Not needed any more Originally to break down the cellulose found in grass etc 11 of 14 Caecum Water is absorbed from semi solid faeces. Mucosa has villi, but no microvilli. 12 of 14 Colon Faeces contain cellulose, cholesterol, bile, mucus, cells, bacteria and water 13 of 14 Rectum and anus Rectum is the final section of the intestine where the faeces are stored. Anus is where egestion occurs. This is controlled by the anal sphincter 14 of 14
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