Organization

• Large multicellular organisms are made up of organ systems.
• Similar cells are organised into tissues.
• Tissues are organised into organs.
• Organs are organised into organ systems.
• Enzymes are catalysts produced by living things.
• A catalyst is a substance which increases the speed of a reaction without being changed or used up in the reaction.
• Enzymes have special shapes so they can catalyse reactions.
• Enzymes need the right temperature and pH or they will denature.
• Digestive enzymes break down big molecules.
• Carbohydrates convert carbohydrates into simple sugars.
• Amylase is an example of a carbohydrase, it breaks down starch.
• Amylase is made in the salivary glands, the pancreas and the small intestine.
• Proteases convey proteins into amino acids.
• Proteases are made in the stomach, the pancreas and the small intestine.
• Lipases convert lipids into glycerol and fatty acids.
• Lipases are made in the pancreas and the small intestine.
• Bile neutralises the stomach acid and emulsifies fats.
• The liver produces bile.
• The gall bladder stores bile before its released into the small intestine.
• The large intestine is where excess water is absorbed from the food.
• The rectum is where the faeces are stored before they go through the anus.
• The stomach pummels the food with its muscular walls and produces pepsin.
• The stomach produces hydrochloric acid to kill bacteria and to give the right pH for the protease enzyme to work.
• Benedict's test for sugars.
• Iodine solution to test for starch.
• Biuret test to test for proteins.
• Sudan III fest to test for lipids.
• The lungs are in the thorax.
• Alveoli carry out gas exchange in the body.
• The heart contracts to pump blood around the body.
• Blood flows into the two atria from the vena cava and the pulmonary vein.
• The atria contract, pushing the blood into the ventricles.
• The ventricles contract, forcing the blood into the pulmonary artery and the aorta and out of the heart.
• The blood floes to the organs through arteries and returns through veins.
• The heart has a pacemaker.
• Arteries carry the blood away from the heart.
• Capillaries are involved in the exchange of materials at the tissues.
• Veins carry blood to the heart.
• Arteries carry blood under high pressure.
• Capillaries have thin walls that are only one cell thick, very small lumen and nucleus of cell.