B4 - Organising Animals and Plants - 4.1 The Blood

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  • Created by: E.Grace
  • Created on: 23-04-20 10:21
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  • B4 - Organising Animals and Plants
    • 4.1 - The Blood
      • The Components of the Blood
        • Blood is a unique tissue
          • Based on a liquid called plasma
            • Plasma carries red blood cells, white blood cells and platelets suspended in it.
              • Also carries many dissolved substances around your body
          • Average person has 4.7 - 5L of blood
      • The Blood Plasma as a Transport Medium
        • blood plasma is a yellow liquid
          • plasma transports all of your blood cells and some other substances around your body
        • waste carbon dioxide produced by the cells is carried to the lungs
        • Urea formed in liver from breakdown of excess proteins is carried to kidneys where it's removed from blood to form urine
        • small soluble products of digestion pass into plasma from small intestine and are transported to the individual cells
      • Red Blood Cells
        • more red blood cells than any other type of blood cell in your body
          • about 5 mill in each cubic millimetre of blood
          • these cells pick up oxygen from the air in your lungs and carry it to the cells where it's needed
        • Adaptations
          • are biconcave discs - being concave (pushed in)on both sides
            • gives then an increased surface area to volume ratio for diffusion
          • packed with a red pigment called haemoglobin that binds to oxygen
          • have no nucleus - making more space form haemoglobin
      • White Blood Cells
        • much bigger than red blood cells and there are fewer of them
        • have a nucleus
        • form part of the body's defence system against harmful microorganisms
        • some white blood cells (lymphocytes) form antibodies against microorganisms
        • some form antitoxins against poisons made by microorganisms
        • others  (phagocytes) engulf and digest invading bacteria and viruses
      • Platelets
        • small fragments of cells
        • have no nucleus
        • are very important in helping the blood to clot at the site of a wound
          • blood clotting is a series of enzyme-controlled reactions that result in converting fibrinogen into fibrin
            • produces a network of protein fibres that capture lots of red blood cells and more platelets to form a jelly-like clot that stops you bleeding to death
            • the clot dries  and hardens to form a scab
              • protects the new skin as it grows and stops bacteria entering the body through the wound
      • Key Points
        • The blood, blood vessels and heart make up the human circulatory system which transports substances to and from the body cells
        • Plasma has blood cells suspended in it and transports proteins and other chemicals around the body
        • Your red blood cells contain haemoglobin that binds to oxygen to transport it from the lungs to the tissues
        • White blood cells help to protect the body against infection
        • Platelets are cell fragments that start the clotting process at wound sites
      • What does blood do?
        • transport
          • transports substances from one part of the body to another
        • protection
          • helps to defend against diseases
        • regulation
          • keeps conditions right for the working of our cells

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ktnowheels

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what is the point of this, it is only partially there.

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