DOUBLE CIRCULATORY SYSTEM

• WHAT TYPE OF CIRCULATORY SYSTEM DO MAMMALS HAVE?

  closed, double circulatory system
• WHAT DOES THE CLOSED PART MEAN?

  blood remains within blood vessels
• WHAT DOES THE DOUBLE PART MEAN?

  blood passes through the heart twice in each circuit
• WHAT DO EACH OF THE CIRCUITS DO?

  one delivers blood to lungs, the other delivers blood to the rest of the body
• WHY IS A DOUBLE CIRCULATORY SYSTEM REQUIRED IN MAMMALS?

  to manage pressure of blood flow
• AT WHAT PRESSURE DOES BLOOD FLOW THROUGH THE LUNGS AT?

  lower pressure
• WHY DOES BLOOD FLOW THROUGH THE LUNGS AT A LOWER PRESSURE?

  • prevents capillary damage in alveoli
  • reduces speed of blood flow, making more time for gas exchange
• WHAT HAPPENS TO BLOOD AFTER PASSING THROUGH THE HEART?

  oxygenated blood from lungs, goes back through the heart to be pumped out at a higher pressure to the rest of the body
• WHAT DOES THE HIGHER PRESSURE OF BLOOD PUMPED OUT OF THE LUNGS ENSURE?

  blood reaches all respiring cells in the body
• VESSELS THAT TRANSPORT DEOXYGENATED BLOOD?

  • veins
  • pulmonary artery
  • vena cava
  • hepatic vein
  • renal vein
• VESSELS THAT TRANSPORT OXYGENATED BLOOD?

  • arteries
  • pulmonary vein
  • aorta
  • hepatic artery
  • renal artery
• HOW DOES DEOXYGENATED BLOOD ENTER THE HEART?

  vena cava (into the right atrium)
• HOW DOES DEOXYGENATED BLOOD EXIT THE HEART?

  pulmonary artery (out the right ventricle, into the lungs)
• HOW DOES OXYGENATED BLOOD ENTER THE HEART?

  pulmonary vein (from lungs into left atrium)
• HOW DOES OXYGENATED BLOOD LEAVE THE HEART?

  aorta (out left ventricle)