Biology-the heart

• The heart is an organ that pumps blood around the body in a double Circulatory System
• The right ventricle pumps blood to the lungs and the left ventricle pumps blood to the body
• Gaseous exchange occurs in the lungs
• The natural resting heart rate is 60 group of cells that act as a pacemaker located in the right atrium
• Artificial pacemakers are used to correct irregularities in the heart rate
• Types of blood vessels

  • Arteries
  • Veins
  • Capillaries
• Arteries


  • Have thick muscle / elastic walls to accomodate blood to pump
  • Always carry blood away from the heart
  • Carry oxygenated blood except for the pulmonary artery
• Connective tissue provides strength and support in blood vessels
• When a blood vessel is narrow, blood flow is restricted
• Coronary heart disease


  A non-communicable disease where fatty material builds up inside the coronary arteries, narrowing them and reducing the flow of blood through the heart muscle. This leads to a lack of oxygen and energy for the heart.
• Coronary heart disease


  1. Fatty material builds up inside the coronary arteries

  2. Narrowing of the coronary arteries

  3. Reduced blood flow through the heart muscle

  4. Lack of oxygen and energy for the heart
• Stents


  • A wire mesh tube used to keep a narrowed or blocked coronary artery open
  • Made from metal alloys
  • Do not cause an immune response
  • Can be less effective and offer less long-term solution compared to surgery
• Statins


  Drugs widely used to reduce blood cholesterol levels, which slows down the rate of fatty material deposit
• Patients often experience side effects from statins, e.g. headaches, muscle pain
• Faulty heart valves


  • Can become leaky, preventing the valves from opening fully
  • Can cause a backflow of blood and fluid build-up in the lungs
  • Can be replaced with biological or mechanical valves
• Biological heart valves


  Made from human donor tissue or animal tissue
• Mechanical heart valves


  Made from strong, durable metal
• Heart transplant


  • Improves quality of life
  • Few donor hearts available
  • Long recovery time
  • Risk of rejection by the body's immune system
• Immunosuppressant drugs must be taken for life to prevent the body rejecting a transplanted heart
• Evaluation of heart treatment methods

  • Replacing heart valves
  • Stents
  • Statins
  • Heart transplant
• Advantages


  • Restore blood flow through the heart
  • Reduce risk of heart attack
  • Decrease bad cholesterol, increase good cholesterol
  • Improve quality of life
• Disadvantages


  • Biological valves may wear out
  • Mechanical valves can cause blood clots
  • Stents have a short recovery time but may not be effective long-term
  • Few donor hearts available
  • Long recovery time for transplants
  • Risk of rejection with transplants
  • Statins have side effects and are not suitable for some conditions
• Effect on the body of a blocked coronary artery

  1. Less blood containing Oxygen and glucose flows to heart

  2. Heart cells aerobically respire less

  3. Muscle cells anaerobically respire more

  4. Less energy is released

  5. Lactic acid is produced

  6. Contraction is less efficient and less blood is pumped around the body

  7. Muscles become fatigued and the person gets tired and breathless
• Because of the blocked coronary artery

  Cells are breathing more to try and get extra oxygen
• coronary artery supplies the heart itself with blood so that it gets oxygen and glucose that it needs for the cells to respire and release energy.
• If coronary artery gets blocked blood is still supplied to the body it just doesn’t flow to the heart muscle. This is was causes a heart attack