Specialisation

• Neutrophils (a type of white blood cell) defend the body against disease. Their flexible shape allows them to engulf foreign particles or pathogens. The many lysosomes in their cytoplasm contain digestive enzymes to break down the engulfed particles.
• Erythrocytes (red blood cells) carry oxygen in

  the blood. The biconcave disc shape provides a large surface area for gas exchange. They have

  no nucleus so there's more room for haemoglobin, the protein that carries oxygen.