Heart, Lungs and Blood Vessels

• Heart


  A hollow and muscular organ that pumps blood throughout the body

  
• Lungs


  The main organs of the respiratory system, responsible for gas exchange where oxygen is exchange with carbon dioxide in the blood

  
• Gaseous exchange


  The process where oxygen is taken in from the air and exchanged for carbon dioxide

  
• Left ventricle


  Pumps oxygenated blood to the body through the aorta

  
• Right ventricle


  Pumps deoxygenated blood to the lungs through the pulmonary artery

  
• Atria


  Upper chambers of the heart that receive blood, the right atrium receives blood from the vena cava and the left atrium receives blood from the pulmonary vein

  
• Aorta


  The largest artery in the body, carries oxygenated blood to the body from the left ventricle

  
• Vena cava


  The largest vein in the body, carries deoxygenated blood from the body back to the heart, specifically to the right atrium

  
• Pulmonary artery


  Carries deoxygenated blood from the heart to the lungs

  
• Pulmonary vein


  Carries oxygenated blood from the lungs to the heart

  
• Coronary arteries


  Blood vessels that supply the muscle of the heart

  
• Trachea


  Allows air to pass to and from lungs

  
• Bronchi


  Two short branches at the lower end of the trachea that carry air into the lungs

  
• Alveoli


  Tiny sacs of lung tissue where gaseous exchange takes place with the blood

  
• Capillary network


  An interconnecting network of capillaries surrounding the alveoli

  
• Arteries


  Blood vessels with thick walls, a narrow lumen and elastic fibres, they carry blood away from the heart

  
• Veins


  Blood vessels with valves to prevent the back-flow of blood, thin walls and a large lumen, they carry blood back to the heart

  
• Capillaries


  Smallest and thinnest blood vessels where the exchange of molecules takes place, they consist of a single layer of cells

  
• Blood flow rate


  The volume of blood passing through a blood vessel per unit of time
• Pacemaker


  The natural resting heart rate is controlled by a group of cells in the right atrium that act as a pacemaker

  
• Artificial pacemaker


  Electrical devices used to correct irregularities in the heart rate

  
• Double circulatory system


  The human circulatory system is a double system that has a circuit linking the heart and lungs and a circuit that links the heart to the rest of the body