Blood

• Components of blood

  Plasma, red blood cells, white blood cells, platelets
• Red blood cells lack nuclei which results in biconcave shape
• RBC carry oxygen from lungs to the body tissue
• RBC carry oxygen from lungs to the body tissue
• The cytoplasm is rich in haemoglobin
• Haemoglobin is a molecule that can bind oxygen and is responsible for the red colour
• Biconcave shape increases the surface area to volume ratio which maximises the diffusion rate of oxygen
• RBC shape allows it to squeeze through the smallest capillaries in the body
• WBC like macrophages and phagocytic engulf and digest pathogens
• Some WBC like lymphocytes produce a protein called antibody
• Platelets allow blood clotting (coagulation) which is an important process that prevents excessive bleeding and pathogens
• Fibrin is an insoluble protein formed from a soluble protein, fibrinogen, present in the plasma
• Fibrin forms fibrin mesh that impedes the flow of blood and entraps more platelets and blood cells to block the wound, preventing further blood loss and inhibiting the entry of pathogens
• Plasma is 91.5 percent water
• Plasma acts as a solvent for important proteins such as hormones and antibody, nutrients, ions and carbon dioxide