Transport in Humans

• Plasma contains mainly water with dissolved substances such as soluble food substances (glucose, amino acids, etc)
• Plasma contains dissolved gases such as carbon dioxide, salts, urea and hormones
• Red blood call is produced in bone marrow and destroyed at the spleen
• Plasma transports blood cells, nutrients around the body
• Plasma transports waste products like urea to the kidney, lungs for removal
• Haemoglobin combined with oxygen to form oxyhaemoglobin
• Red blood cell has a biconcave, circular shape to increase surface area to volume ratio for efficient uptake of oxygen
• White blood cells are produced in the bone marrow, they are destroyed in the spleen
• There are two types of white blood cells; phagocytes & lymphocytes
• What is the function os phagocytes?

  Engulfs, ingests and digests pathogens (foreign particles)
• Phagocytes have a lobed nucleus
• what is the function of lymphocytes?

  produce antibodies that destroys pathogens and foreign particles
• Lymphocytes have a circle nucleus
• Lymphocytes produces antibodies when

  • They recognise foreign particles
  • Causes bacteria to clump together for easy ingestion by phagocytes
  • neutralise the toxins produced by bacteria
• What is tissue rejection?

  When the white blood cells do not recognise the foreign organ transplantation and starts attacking it. They treat it like a foreign body.
• How to we reduce the risk of tissue rejection?

  • Must be genetically similar as possible to have a tissue match

  • the use of immunosuppressive drugs, this inhibits the responses of recipients immune system to reject the transplant.
• Platelets are important for the clotting of blood.
• The platelets contain an enzyme (thrombin) that converts a blood protein, fibrinogen to insoluble threads of fibrin to form a mesh or network which traps red blood cells to form a clot.
• Arteries move away from the heart
• Veins move towards the heart