Digestive system
- Created by: oliviaeve
- Created on: 27-04-16 09:53
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- Digestive system
- Oesophagus
- The tube that takes food from
the mouth to the stomach
- using waves of muscle contractions called peristalsis; the muscle layer is thick to help with this
- Mucus is secreted from tissues in the walls, to lubricate the food’s passage downwards
- The tube that takes food from
the mouth to the stomach
- Stomach
- A small sac with many folds which allow it to expand
- The entrance and exit are controlled by the sphincter muscles
- The gastric juice produced here help digest food
- It consists of hydrochloric acid, pepsin, and mucus
- Pepsin hydrolyses proteins into smaller polypeptide chains and only works in acidic conditions
- The mucus protects the stomach from acid damage and pepsin
- It consists of hydrochloric acid, pepsin, and mucus
- Peristalsis of the stomach churns the food in a fluid called chyme
- Small intestine
- Chyme is moved along it by peristalsis
- 2 main parts
- duodenum
- bile (an alkali) and pancreatic juice neutralises the chyme and breaks it down
- Bile emulsifies lipids in the food
- It breaks up large globules into smaller globules = increases surface area
- Lipase digestion more efficient
- It breaks up large globules into smaller globules = increases surface area
- Bile emulsifies lipids in the food
- bile (an alkali) and pancreatic juice neutralises the chyme and breaks it down
- ileum
- Small, soluble molecules are absorbed
- villi in the gut wall by diffusion, facilitated diffusion and active transport
- villi + microvilli increase surface area so that soluble molecules are absorbed quickly
- villi in the gut wall by diffusion, facilitated diffusion and active transport
- Small, soluble molecules are absorbed
- duodenum
- Oesophagus
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