Blood/Circulatory System

• Blood is what

  A tissue found in the body
• Tissue


  • Protects the body from harmful microorganisms
  • Transports and delivers substances to different parts of the body
• Cells of this tissue

  Made in the bone marrow
• Components of this tissue

  • Plasma
  • Platelets
  • White blood cells
  • Red blood cells
• Platelets


  Small fragments of cells which allow the blood to clot at the site of a wound to stop bacteria entering through the wound
• Red blood cells


  • Contain haemoglobin which attaches to oxygen, delivering it to all body cells for respiration
• White blood cells


  • Protect the body against harmful microorganisms called pathogens
  • Lymphocytes produce antibodies which attach onto pathogens
  • Phagocytes engulf and digest pathogens
• Blood plasma


  A yellow liquid that transports all your blood cells and other dissolved substances around the body
• What blood carries


  • Oxygen
  • Dissolved food
  • Waste products
  • Hormones
• Donated blood can help many people with blood disorders live normal lives
• Thalassaemia major


  A rare blood disorder that means she cannot produce normal haemoglobin
• Haemophilia


  A deficiency of the clotting factor in the blood that works with the platelets to stop excessive bleeding
• Blackfan diamond anaemia


  In which the body tissues do not get enough oxygen
• ITP


  A condition that causes bruising, nosebleeds and other symptoms
• Red blood cells


  • Biconcave discs - gives them an increased surface area to volume ratio for diffusion
  • Packed with a red pigment called haemoglobin that binds to oxygen
  • No nucleus, making more space for haemoglobin
• White blood cells


  • Much bigger than red blood cells and there are fewer of them
  • Have a nucleus and protect the body against harmful microorganisms
  • Form antibodies
  • Form antitoxins against toxins (poisons) made by microorganisms
  • Phagocytes - engulf and digest invading bacteria and viruses
• Platelets


  • Small fragments of cells, they have no nucleus
  • Very important in blood clotting at the site of a wound
• Blood clotting


  1. An enzyme controlled reaction converting fibrinogen to fibrin

  2. Producing a network of protein fibres that captures lots of red blood cells and more platelets to form a jelly like clot that stops you bleeding to death

  3. The clot hardens to form a scab protecting new skin as it grows and stops bacteria entering through the wound
• Components of blood


  • Plasma
  • Red blood cells
  • White blood cells
  • Platelets
• Red blood cells


  • Biconcave shape to increase surface area to volume ratio, so more oxygen can diffuse in
  • Haemoglobin to bind to oxygen
  • No nucleus or mitochondria to allow more space for haemoglobin
• During exercise


  • Breathing rate increases to get more oxygen into the blood
  • Heart rate increases to deliver oxygen and nutrients to respiring cells quicker for more energy
  • Increased heart rate also removes carbon dioxide faster
• Blood


  A tissue made of many cells working together
• Septum


  • Separates the left and right side of the heart
  • A hole in the septum can be a problem
• Where blood comes out of the heart

  • Blood vessels
• Where blood goes into the heart

  • Blood vessels
• When blood enters the heart

  It goes into the atria and then blood is forced into the ventricles at the bottom
• Valves


  Prevent blood from flowing backwards
• The septum separates the left and right side of the heart
• Arteries


  Carry blood away from the heart and to the body's organs
• Veins


  Carry blood towards the heart from the organs
• Capillaries


  Connect veins to arteries and is where nutrients and waste products are exchanged with the body's cells
• The journey of the blood

  1. The muscular walls of the heart are thicker in the ventricles compared to the atria

  2. The heart muscle is thicker in the left side of the heart compared to the right side of the heart

  3. The valves are so important
• Coronary arteries


  Supply the heart's cells with oxygenated blood for respiration
• Coronary heart disease


  The coronary arteries become narrow, mainly from the build up of fatty material inside of the vessels
• Reduced blood flow through the coronary arteries

  • Reduces the supply of oxygen and glucose to the heart muscle
  • The heart's cells can't respire and start to die
  • This can cause pain, heart attack, and death
• Statins


  • Drugs which reduce blood cholesterol so slows down fatty deposit buildup
• Stents


  • A metal mesh structure that holds open the artery
• Coronary bypass surgery


  • Using other blood vessels to create another path for blood to get to the heart's cells
• Stents work for badly blocked arteries where they cannot help</b>
• Bypass surgery is expensive and involves the risks associated with a general anaesthetic