Lungs and Heart

• Vena cava


  Carries deoxygenated blood from the body to the heart
• Right atrium


  Segment of the heart that receives deoxygenated blood from body
• Right ventricle


  Pumps deoxygenated blood from the heart to the lungs
• Pulmonary artery


  Carries deoxygenated blood from the heart to the lungs
• Pulmonary vein


  Carries oxygenated blood from the lungs to the heart
• Left atrium


  Segment of the heart that receives oxygenated blood from lungs
• Left ventricle


  Pumps oxygenated blood away from the heart to the body
• Aorta


  Carries oxygenated blood away from the heart to the body
• Semilunar valve


  Flaps that prevent backflow of blood
• Pacemaker cells


  Regulate heart rate by sending electrical impulses to the heart muscles (found on wall of right atrium)
• Blood flow


  • Deoxygenated blood on right side
  • Oxygenated blood on left side
• Humans have a double circulatory system (it is made up of two loops joined together)
• First loop


  Heart pumps blood to the lungs to be oxygenated and then it returns to the heart
• Second loop


  Heart pumps blood all around the body to supply the cells so they can exchange substances with blood before returning to the heart
• Red blood cells


  • Carry oxygen around the body
  • Biconcave shape - bigger surface area
  • No nucleus - holds more oxygen
  • Contains haemoglobin
• White blood cells


  • Protect against infections
  • Kill bacteria
  • Have nucleus
• Platelets


  • Help the blood clot on wounds
  • Prevent blood loss
  • Prevent microbes getting in through skin
• Plasma


  • Carry CO2
  • Carry hormones
  • Carry nutrients
• To calculate the rate of blood flow


  Divide the volume of blood by the time taken for it to pass
• Capillaries


  • Exchange minerals and take away waste like CO2
  • 1 cell thick to easily exchange substances (short diffusion distance)
  • Permeable walls so substances can diffuse in and out
  • Very small lumen
• Arteries


  • Carry blood away from heart to body
  • Thick, elastic walls to cope with high pressure or it'd burst
  • Narrow lumen
  • Elastic fibres so they can stretch and spring back
• Veins


  • Carry blood to heart
  • Lower pressure so walls not as thick
  • Big lumen to help blood flow
  • Has valves to prevent back flow