Blood Components and Their Jobs
Ever wondered what's actually floating around in your bloodstream? Blood has four main components, each with a specific job that keeps you functioning.
Plasma is the liquid part that carries dissolved substances like carbon dioxide, digested food, urea, and hormones around your body. Think of it as your body's delivery service, transporting chemical messages and waste products wherever they need to go.
Red blood cells are your oxygen carriers, packed with haemoglobin that grabs oxygen in your lungs and delivers it to every cell. They're brilliantly designed - no nucleus means more space for haemoglobin, and their biconcave shape gives maximum surface area for gas exchange. Plus, they're small and flexible enough to squeeze through the tiniest blood vessels.
Quick Tip: Remember that red blood cells are thin to help diffusion happen faster - this design feature often comes up in exam questions!
White blood cells are your immune system's army. Phagocytes (70% of white cells) literally eat invading microorganisms through phagocytosis, whilst lymphocytes (25% of white cells) produce antibodies to fight off infections and diseases.