The Circulatory System

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The Circulatory System

• Pasterik 2006

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The Vertebrate Heart Unlike the heart of a
fish, the human heart is a DOUBLE LOOP. That
is, it goes from the heart, to the lungs, back to
the heart, and then to the body. (In fish,
blood goes from the heart, passes through the
gills and onto the rest of the body)
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Double loop circulation is more efficient,
because it gives the heart an extra pump to move
blood to the body.The mammalian heart has 4
chambers, so that oxygenated and deoxygenated
blood is completely separated - again increasing
efficiency.The hearts of amphibians and
reptiles have only 3 chambers, blood mixes in the
ventricle. (Though crocodiles do have a 4
chambered heart)
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How big is your heart?

• The heart is roughly the size of your fist in
  humans.

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The Anatomy of the Human Heart

• The heart is divided into 4 chambers
• 1. Right Atrium (RA) 2. Right Ventricle (RV) 3.
  Left Atrium (LA) 4. Left Ventricle (LV) (largest
  part of the muscle,
• pumps blood to rest of body)
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• The right side of the heart collects oxygen poor
  blood and pumps it to the lungs
• The left side of the heart collects oxygen rich
  blood (from the lungs) to the rest of the body

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Valves

• Tricuspid valve- between right atrium and right
  ventricle
• Bicuspid valve - between the left atrium and the
  left ventricle
• Semilunar (Pulmonary valve) - is at the exit of
  the Right Ventricle to pulmonary artery
• Semilunar (Aortic valve) - is at the exit of the
  Left Ventricle to the Aorta

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ContractionsSystole - ventricle contracts,
pumping blood to the lungs and to the
bodyDiastole - atrium contracts, pumping blood
to the ventricle
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Flow of Blood

• Blood from the body flows
• 1. to the Superior and Inferior Vena Cava,2.
  then to the Right Atrium3. through the Tricuspid
  Valve4. to the Right Ventricle5. through the
  Pulmonary Valve6. to the Pulmonary Artery7. to
  the Lungs

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The blood picks up oxygen in the lungs, and then
flows from the lungs

• 1. to the Pulmonary Veins2. to the Left
  Atrium3. through Mitral valve4. to the Left
  Ventricle 5. through the Aortic Valve6. to the
  Aorta7. to the body