Organisation

• The heart

  heart

  A) Right atrium

  B) Vena cava

  C) Valve

  D) Right ventricle

  E) Pulmonary artery

  F) Pulmonary Vein

  G) Left Atrium

  H) Valve

  I) Left Ventricle

  J) Aorta

  
• Lock and Key mechanism

  every enzyme has an active site with a specific shape that fits onto a specific substrate of the substance it is reacting with. The substrate has to fit into the active site for the catalyst to work.
• Change in temperature changes the rate of enzyme reactions. Higher temperatures increase the rate of reaction. If it gets too hot the shape of the enzymes active site changes so the substrate won't fit. The enzyme is denatured.
• All enzymes have an optimum temperatures. (the temperature they work best at - around 40 degress)
• pH also effects enzymes. If it is too high or too low the enzymes active site changes so the substrate won't fit into the enzyme. The enzyme denatures.
• All enzymes have an optimum pH (often pH 7 but enzymes in the stomach work best at pH 2)
• Amylase/carbohydrase breaks down starch into glucose/simple sugars
• Amylase is made in the salivary gland, the pancreas and the small intestine.
• Proteases breaks down proteins into amino acids
• Proteases are made in the stomach pancreas and small intestine
• lipases break down lipids into glycerol and fatty acids.
• Lipases are made in the pancreas and small intestine.
• Bile is produced in the liver and stored in the gall bladder before it is released into the small intestine.
• Bile :)

  The hydrochloric acid in the stomach makes the pH too acidic for enzymes in the small intestine to work properly. Bile is a alkaline - it neutralizes the acid and makes conditions alkaline. It also emulsifies fat into tiny droplets giving a bigger surface area of fat for lipase to break down - making digestion faster.
• Salivary glands produce amylase enzymes in the saliva
• Liver is where bile is produced. Bile neutralises stomach acid and emulsifies fat.
• Gal bladder is where bile is stored before it is released into the small intestine.
• Large intestine is where excess water is absorbed from food.
• Stomach

  1. pummels food with its muscular walls
  2. produces protease enzyme (pepsin)
  3. produces hydrochloric acid : to kill bacteria and also to give the right pH for the protease enzyme to work
• Pancreas produces protease, amylase and lipase enzymes. It releases thes into the small intestine.
• Small intestine.

  1. produces protease, amylase and lipase enzymes to complete digestion
  2. where digested food is absorbed out of the digestive system into the blood.
• Rectum is where faeces is stored before passing through the anus.
• Air breathed in goes through the trachea. This splits into two tubes called bronchi, on each lung. The branches spilt into smaller tubes called bronchioles. The bronchioles end at the small bags called alveoli where gas exchange takes place
• Lungs contain a lot of alveoli surrounded by a network of capillaries . Blood passing next to the alveoli has come from the rest of the body so contains a lot of carbon dioxide and very little oxygen. Oxygen diffuses out of the alveolus into the blood. Carbon dioxide diffuses out of the blood into the alveoli to be breathed out.
• When blood reaches body cells oxygen is released from red blood cells and diffuse into the body cells. At the same time carbon dioxide diffuses out of the body cells and into the blood. It is then carried back to the lungs.
• breathes per minute = number of breaths / number of minutes
• The circulatory system is made up of the heart, blood vessels and blood.
• Humans have a double circulatory system.
• Double circulatory system

  In the first circuit the right ventricle pumps deoxygenated blood to the lungs to take in oxygen. The blood the returns to the heart.

  In the second circuit the left ventricle pumps oxygenated blood around all of the other organs of the body. The blood exchanges its oxygen with body cells and the deoxygenated blood returns the heart.