BLOOD

• blood is a liquid connective tissue containing a liquid part called plasma and blood cells.

  
• plasma is a pale yellow liquid consisting of 90% water and 10% dissolved substances transported in it.


  dissolved sustances: dilute soln of salts, glucose, amino acids, urea, protein, fats
• RED BLOOD CELL (ERYTHROCYTES)

  -RBC transport oxygen around the body

  -they are non nucleated biconcave disk when matured

  -oxygen bounds with the protein haemoglobin present in RBC.

  -life span is three months
• ADAPTATION OF RBC

  • biconcave disk providing large surface area for diffusion
  • do not contain nucleous or mitochondria allowing more space for haemoglobin inside the cell
  • squeez in bell shaped maximising surface area for efficient diffusion
• WHITE BLOOD CELLS (LEUCOCYTES)

  • they are nucleated cells which are much larger than RBC and protect us against diseases.
  • they have the ability of leaving the blood vessels to invade diseases tissues. life span: few days only
• LYMPHOCYTE (AGRANULAR)

  • produce antibodies which help in destruction of foreign bodies ANTIBODIES IMMOBILISE bacteria by attaching to their flagella
  • Antibodies are Y shaped proteins with a shaped that is complementary to the antigen..These are specific immune response.
  • they have round cells containing a nucleous and a non-granular cytoplasm. invoved in tissue rejection that ocuurs during transplantation.
• PHAGOCYTES(GRANULAR)

  • THEY engulf and destroy foreign bodies. this is a non-specific immune system.
  • they are larged cells having an irregular shaped containing a multi-lobed nucleous and a granuar cytoplasm.
• phagocyte cell

  
• PLATELETS (THROMBOCYTES)

  • they are fragments of cell that are involved in blood clotting where the skin has been cut and act a barrier for pathogens.
  • they release chemicals that cause soluble fibrinogen proteins to convert into insoluble fibrin which is a fibre like structure to form a mesh
  • the mesh across the wound trapped RBC forming a clot