IGCSE Biology -The digestive system

• mucus


  a thick green liquid which helps things to slide along
• capillaries


  any of the small blood vessels connecting arteries with veins
• micro-villi


  Each villi has this and it increases the surface area of the villi
• villi


  the lining of the ileum is covered in these to create a larger surface area for absorbing the digested food into the blood
• optimum


  the best or most appropriate (e.g. of a time or temperature)
• maltase


  a kind of carbohydrase which breaks down maltose into glucose
• amylase


  a kind of carbohydrase which breaks down starch into sugars (maltose)
• lipase

  a digestive enzyme which breaks down lipids
• proteases


  a digestive enzyme which breaks down proteins
• carbohydrases


  a digestive enzymes which breaks down carbohydrates
• illeum


  this is where the soluble food molecules are absorbed through the wall and into the blood capillaries surrounding it
• duodenum

  enzymes break down food here
• faeces


  waste/poo
• anus


  hole which waste/faeces comes out of
• rectum


  storage for waste/faeces before it comes out
• appendix


  an organ which has no use in humans
• pancreas

  an organ which produces digestive enzymes: carbohydrases (eg amylase) proteases and lipases)
• large intestine


  fat and short intestine where water is absorbed from food
• small intestine


  long and thin intestine; In the first part of this organ (the duodenum) enzymes break down food in the second part (the illeum) the soluble food molecules are absorbed through the wall and into the blood capillaries surrounding it
• emulsifies


  breaks down into smaller droplets
• gall bladder


  an organ where bile is stored
• bile


  a substance made in the liver that breaks down fats or lipids
• liver


  an organ in the body which makes bile (and does other stuff too!)
• bacteria


  germs
• hydrochloric acid

  HCI
• digest


  to break down food
• digestion


  the chemical and mechanical breakdown of food; coverts large insoluble molecules into small soluble molecules, which can be absorbed into the blood
• enzymes


  biological catalysts which control chemical reactions
• protease


  an enzyme that breaks down proteins
• secrete


  to release
• gastric juices


  a digestive fluid formed in the stomach which is acidic (contains hydrochloric acid and protease enzymes) and digests proteins
• stomach


  a muscular bag that holds food for a few hours and mixes it with gastric juices
• peristalsis


  when the muscles push the food along the gut
• oesophagus


  a muscular tube leading from the mouth to the stomach