Blood smear, light micrograph

Blood smear. Light micrograph showing human blood cells. Erythrocytes (red blood cells) are pink. They make up the majority of blood cells and carry oxygen to body tissues and carbon dioxide to the lungs. Two types of white blood cell (purple) can also be seen. They are, neutrophils (lower left and right) and a monocyte (upper centre). White blood cells are part of the body's immune system. Neutrophils are the most abundant white blood cell. They engulf and digest invading bacteria. Monocytes are the largest white blood cell. They engulf and digest invading bacteria and cell debris. Also seen are platelets (small purple particles), which are cell fragments that play an essential role blood clotting. Magnification: x300 when printed at 15cm wide., Photo by EYE OF SCIENCE/SCIENCE PHOTO LIBRARY