CB5

• Arteries

  has thick walls which are strong and elastic because the blood pumps out at high pressure.carries blood away from the heart. oxygenated blood
• Capillaries 


  Small. Supplies food and oxygen and takes away waste. Have permeable walls so substances can diffuse in and out. Thin walls so the substances can diffuse in and out quickly
• Veins

  thin walls as the veins carry blood at low pressure. veins have valves to stop the blood flowing backwards. Carries deoxygenated blood to the heart
• Four chambers of the heart

  Right atrium, left atrium, right ventricle, left ventricle
• How blood flows through the heart

  deoxygenated blood comes in through vena cava to right atrium. Passes through a valve to the right ventricle, which pumps the blood to the lungs through the pulmonary artery. The left atrium then gets oxygenated blood from the lungs which comes through the pulmonary vein. Oxygenated blood then goes to the left ventricle which pumps it around the whole body through the aorta
• Cardiac output equation

  Heart rate x stroke volume
• Role of red blood cells

  to carry oxygen from the lungs to all the cells in the body
• Red blood cells

  They have a large surface area for absorbing oxygen

  they have a substance called haemoglobin which allows the red blood cells to carry oxygen

  they dont have a nucleus so they have Space to carry oxygen
• Role of White blood cells

  Lymphocytes (type of white blood cell) produce antibodies against micro organisms

  phagocytes - can change shape to kill micro organisms
• physical barriers 


  stop pathogen from getting in the body or making it hard to do so
• Chemical barriers 


  react with substances that either kill the pathogen or make it inactive
• Cardiovascular diseases


  diseases which affect the heart and blood vessels
• why might an obese person be more at risk for cardiovascular disease?

  Because there is more strain on vital organs
• causes of cardiovascular disease


  unhealthy diet

  harmful use of alcohol

  physical inactivity

  tobacco use

  high blood pressure/high cholesterol

  weight
• angina 


  chest pain caused by restricted blood flow to the heart muscle
• how does tobacco cause cardiovascular disease?

  substances from tobacco smoke damage the artery lining

  fat builds up in the artery wall at the site of damage making the artery narrower
• Bacteria


  tuberculosis , cholera, food poisoning
• Viruses 


  AIDS, influenza, mumps, measles
• Fungi 


  Athletes foot
• Way to reduce the spread of pathogens 


  washing our hands

  don't sneeze or cough
• How do pathogens get in our bodies

  mouth, nose, cuts/wounds, eyes
• why is it advisable for people high altitude areas to learn how to use mosquito nets?


  because malaria is spread by a vector by being carried in the blood after sucking it from an infected person. Its also caused by a micro organism called plasmodium which can only cause malaria if it finishes it growth cycle. In high temperatures this allows malaria to be spread. Using mosquito nets could prevent the spread. using mosquito nets could prevent the spread of malaria by not letting the mosquito's near people to infect them