The Circulatory System

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The Circulatory System

• By D. Reis

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The Circulatory System

• The circulatory system has 4 principal functions
• Transportation of oxygen and carbon dioxide
• Distribution of nutrients and transport of wastes
• Maintenance of body temperature
• Circulation of hormones

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Pulmonary Circuit

• The right side of the heart pumps deoxygenated
  blood to the lungs, where the blood picks up
  oxygen and returns to the left side of the heart.

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The Systemic Circuit

• The left side of the heart then pumps the
  oxygenated blood out to all parts of the body, to
  deliver oxygen.

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The Circulatory System

• If you are confused as to which way the blood
  flows through the heart, try this saying "When it
  leaves the right, it comes right back, but when
  it leaves the left, it's left."

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Heart Structure

• Septum wall of muscle separating the ventricles
• Atrium a thin- walled chamber of the heart that
  receives blood from veins
• Ventricle a muscular, thick-walled chamber that
  delivers blood to the arteries.

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Heart Structure

• Atrioventricular valves- valves separating the
  atria and ventricles. The AV valves ensure
  one-directional flow.
• The right AV- valve is also known as the
  tricuspid valve
• The left AV-valve is also known as the mitral or
  bicuspid valve

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Atrioventricular Valves
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Semilunar Valves

• Semilunar valves valves separating the
  ventricles and arteries that prevent the backflow
  of blood from the arteries to the ventricles

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The Difference between Arteries and Veins

• Arteries usually carry oxygenated blood away from
  the heart to tissues.
• Veins usually carry de-oxygenated blood from the
  tissues back to the heart.
• THERE ARE SOME IMPORTANT EXCEPTIONS!!!!

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Exceptions in the Circulatory System

• Pulmonary Veins carry oxygenated blood from the
  lungs to the left atrium
• Pulmonary Artery carries deoxygenated blood
  from the heart to the lungs

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The Right Side of the Heart

• The right atrium receives deoxygenated blood from
  the superior vena cava and the inferior vena cava
  (2 large veins). The right atrium pumps blood
  into the right ventricle . The right ventricle
  pumps blood into the lungs via the pulmonary
  artery. In the lungs the deoxygenated blood
  receives oxygen.

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The Left Side of the Heart

• The left atrium receives oxygenated blood from
  the pulmonary veins. The left atrium pumps blood
  into the left ventricle. The left ventricle
  pumps oxygenated blood to all parts of the body
  via the AORTA ( the largest artery in the body)
• Both ventricles pump blood out of the heart at
  the same time.

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Contraction of the Heart

• Sinoatrial node (SA) node sets the hearts
  beat rate at about 70 beats per minute
• Atrioventricular node (AV) - passes the nerve
  impulses to the ventricles allowing them to
  contract
• Purkinje fibers nerve fibers in the septum that
  branch carrying nerve impulses

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Heart Sounds

• Lubb Dubb heart sounds are caused by the
  closing of the heart valves.
• Lubb sound occurs when the AV valves shuts during
  systole
• Dubb sound occurs when semilunar valve shuts
  preventing blood from reentering the ventricles

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Heart Murmur

• Occurs when the valves do not close completely
• A gurgling sound is produced from the blood
  rushing from the ventricles back to the atria and
  can be detected with the use of a stethoscope.
• The heart compensates for decreased oxygen
  delivery by beating faster.

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