Blood: It is a specialized circulating tissue composed of cells suspended in a fluid.

Blood cells are of three types

• Erythrocytes/RBC
• Leucocytes/WBC
  • Leucocytes Five different types of leucocytes have been classified into two main groups
    • Agranulocytes: Lymphocytes and monocytes
    • Granulocytes: Neutrophil, eosinophil, basophil
• Thrombocytes/ platelets.