Digestive system
- Created by: elen roberts
- Created on: 02-05-13 22:31
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- Digestive system
- Alimentary canal
- Oesophagus
- Tube through thorax, no digestion, glands secreet mucus
- Wave of circular muscle contractions open and close the tube and push food through
- Stomach
- Food is stored and churned by muscle into a liquid - chrome and slowly release into S.I.
- Gastric pits lead to gastric glands which secreete gastric juiceto kill bacteria and mucus to lubricate food and protect lining of the stomach
- Small intestine
- First 30cm - duodenum. Most digestion due to Pancriatic juice (amalyse, protiase & lipase) and bile secreeted by liver, stored in gall bladder, aids lipid digestion and nutrialises acid and sodium hydrogen carbonate
- Ileum - final digestion and absorption. Glands produce enzymes, mucus and Sodium hydrogen carbonate
- Large SA - folds, villi and microvilli
- Short distance -one layer of endothelium, and capillary
- High concentration difference - movement of fluids on both sides.
- Large intestine
- Contains vili and mucus glands
- Oesophagus
- Carbohydrates
- Starch + amalayse = maltose + maltase = glucose
- Salivary amalasye
- digestion of starch - mouth, denatures in stomach but kills bacteria
- Pancreatic amalayse
- Digests remaining starch - duodenum. Forms disaccharide maltose. Also digests glycogen
- Disaccharide
- Borken down into monosaccharides by epithelial cells in ileum
- Maltose + maltase = glucose
- Lactose + lactase = glucose + galactose
- Sucrose + sucrase = glucose + fructose
- Glucose
- Absorbed by co-transport. Sodium-potasium ATPase
- Sodium & potassium ions are pumped back out to maintain gradient
- Sodium is the facilitated diffusion protein, glucose is the co-transporter protein
- High concentration of glucose in epithelials, blood diffuses into blood through tissue fluid through a carrier protein and into the blood for use
- Alimentary canal
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