nutrition in humans

• what is digestion: breaking down of large, complex food molecules into smaller, simpler and soluble molecules which can be absorbed into body cells
• label the human digestive system: 1) mouth 2)stomach 3) duodenum 4) oesophagus 5) liver 6) gall bladder 7) pancreas 8) ileum 9) large intestine 10) rectum 11) anus

  
• what happens in the region behind food in oesophagus: circular muscles contract, longitudinal muscle relax causing lumen constriction
• what happens in region of food in oesophagus: circular muscle relax, longitudinal muscle contract causing lumen dilation allowing food to move forward
• what is SF of digested food molecules: S1— epithelial cells of villi have microvilli. F1— increases SA:vol for faster rate of diffusion of digested food molecules. S2— epithelium is one-cell thick. F2— shorter time for digested food molecules to pass through thin membrane. S3— epithelial cells contain many mitochondria. F3— releases energy for active transport of digested food molecules into villi
• what are the role of liver: breakdown of alcohol— detoxification, converts harmful alcohol into harmless acetaldey
• what are the role of liver: breakdown of alcohol— detoxification, converts harmful alcohol into harmless acetaldehyde. breakdown of hormones