The Heart

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The Heart
2
Structure of the Heart

• Two parallel independent systems
• Two different pumps
• Each _at_ atrium
  (auricle) ventricle
• Designating right
  cavity left cavity
• as if you were wearing
• your heart

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Heart Valve replacement
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Function of the Cavities

• Right cavity takes in oxygen poor blood from the
  body
• Pumps it to the lungs
• Left cavity takes oxygen rich blood from the
  lungs
• Returns it to the body

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Functions of the Cavities

• Atrium draws blood in
  from veins
• Ventricle pushes blood
  away through arteries

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Differences Between the Cavities

• Right cavity takes in oxygen poor blood from the
  body sends it to the lungs
• Left cavity takes oxygen rich blood from the
  lungs and sends it to the body through the aorta.
  Its wall is thicker because it has to pump the
  blood throughout the body

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How the Heart Works

• There are two stages in the heart beat cycle
• The diastole (relaxation)
• The systole (contraction)

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Diastole

• In diastole the heart
  relaxes and blood
  goes into the two
  auricles
• Rising pressure in
  each auricles opens
  the tricuspid and
  mitral valves and
  blood flows into
  the ventricles
  

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Systole

• Filled ventricles
  contract and the mitral
  and tricuspid valves
  close
• The filled ventricles
  force the aorta and
  pulmonary valves to
  open
• Blood is then pushed
  into the arteries

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Rate of Heartbeat

• The heart is a muscle is a unique muscle.
• It has the ability to contract spontaneously at a
  regular rate of 80 beats per minute
• That is what creates the pulse

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Rate of Heartbeat

• However this rate is influenced by two nervous
  systems
• Sympathetic
• Parasympathetic

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Sympathetic

• This controls your heart by fear, and adrenaline.
  
• For example when you get scared your heart
  intends to beat faster.
• Your heart is also affected by exercise which is
  another aspect of the sympathetic nervous system

13
Parasympathetic

• This nervous system controls your heart rate when
  you sleep
• Your heartbeat is much slower when you sleep then
  when you are awake because of the function of
  this system

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Heart Disease

• The major form of heart disease is
  atherosclerosis
• In this condition fatty deposits called plaques,
  composed of cholesterol and fats, build up on the
  inner wall of the coronary arteries

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Heart Disease

• Gradual narrowing of the arteries throughout
  life restricts the blood flow to the heart
  muscles.
• Symptoms of this restricted blood flow can
  include
• shortness of breathe
• and a tightening pain in the chest

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Heart Disease

• A heart attack is caused when oxygen supply to
  the heart is suddenly decreased by
• plaque large enough to completely obstruct the
  coronary artery
• when part of the plaque breaks away and lodges
  farther along the artery

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How to Prevent Heart Disease

• Development of fatty plaque is due to excessive
  intake of cholesterol and animal fat and
  especially cigarette smoking
• Evidence suggest that physical exercise may help
  to prevent heart disease and watching what you eat