2 Organisation

• Lable the digestive system

  A) Salivary glands

  B) mouth

  C) stomach

  D) gall bladder

  E) large intestine

  F) rectum

  G) anus

  H) appendix

  I) small intestine

  J) oesophagus

  K) liver

  L) pancreas

  
• What happens in the mouth?

  Mechanical digestion - teeth chew food to break it up into smaller molecules and increase its surface area to volume ratio
• What do the salivary glands?

  Produce amylase in the saliva which begins to digest starch into smaller sugar molecules
• What does the gall bladder do?

  It is where bile is stored before being released to the small intestine
• What does the stomach do?

  • Food is mechanically digested by churning
  • Protease enzymes start to digest proteins
  • HCl is present to kill bacteria and maintain optimum pH for enzymes
• What are the two roles of hydrochloric acid in the stomach?

  • To kill bacteria
  • To maintain optimum pH for enzymes
• What does mechanically churning food do to it in the stomach?

  It turns into a fluid which increases the surface area for enzymes
• Where is the duodenum (small intestine)?


  First part of the small intestine.
• Where is the ileum (small intestine)?


  Second part of the small intestine
• What happens in the duodenum?

  Where food finishes being digested by enzymes produced here and from the pancreas and liver
• What does the pancreas do?


  Produces protease, amylase and lipase enzymes, it releases it to the small intestine
• What does the rectum do?


  Stores faeces before they leave the body
• What does the anus do (digestive system)?

  Where faeces leave the body
• What does the large intestine do?


  Absorbs excess water from the food into the bloodstream
• What does the ileum do?


  It absorbs small food molecules into the bloodstream either by diffusion or the active transport
• What are adaptations of the ileum?


  Long and lined with villi which helps to increase surface area over which absorption takes place
• What does the liver do?

  It is where bile is produced
• What does bile do?


  • Speeds up the digestion of lipids
  • neutralises acid released from the stomach
  • It also emulsifies fat to form small droplets which increases the surface area.
• What does the oesophagus do?

  A tube that connects the mouth to the stomach
• What do carbohydrases break carbohydrates into?


  Simple sugars
• What do proteases break down protein into?

  Amino acids
• What do lipases break down lipids into?

  Glyercol and fatty acids
• Amylase is a carbohydrase which breaks down starch.
• What increases the rate of fat broken down by lipase?

  • Alkaline conditions
  • Large surface area
• Where is carbohydrase produced?

  • Salivary glands
  • Pancrease
  • Small intestine
• Where is protease produced?

  • Stomach
  • pancreas
  • Small intestine
• Where is lipase produced?

  • Pancreas
  • Small intestine
• What are the 4 main things in blood?

  • Red blood cells
  • White blood cells
  • Platelets
  • Plasma
• What is the job of red blood cells?

  To carry oxygen from the lungs to all the cells in the body
• What happens to haemoglobin in the lungs?

  It binds to oxygen to become oxyhaemoglobin
• What is haemoglobin?


  A red pigment inside red blood cells
• What happens to oxyhaemoglobin in the body tissues?

  Oxyhaemoglobin splits up into haemoglobin and oxygen, to release oxygen to the cells
• what are the adaptations of the red blood cell?

  • Biconcave disc - gives a large surface area for absorbing oxygen
  • Don't have a nucleus - allows more room to carry oxygen
• What is the function of white blood cells?


  To defend against infection
• What are some of the jobs of white blood cells?

  • Some change shape to gobble up unwelcome microorganisms, in a process called phagocytosis
  • Others produce antibodies to fight microorganisms as well as antitoxins to neutralise any toxins produced by the microorganism
• What is the different between subcellular structures in white and red blood cells?


  White blood cells have a nucleus
• What are platelets?

  Small fragments of cells, they have no nucleus
• What do platelets do?


  Help the blood to clot at a wound - to stop blood pouring out and to stop microorganisms getting in
• What can a lack of platelets do?


  Cause excessive bleeding and bruising
• What is plasma?


  The liquid that carries everything in the blood