What would life be without blood? Well, without blood we wouldn’t be here nor will be any mammals or any vertebrate. In fact it is fundamental to our survival and so we need to know all about it. You should already know that blood consists of red blood cells, white blood cells, platelets and plasma. In this video we’re going to look at white blood cells in particular. These are our warriors the army inside our body that protects us from infectious diseases and foreign invaders. They may only make up 1% of our blood, but my gosh they are important. Our body has a first line of defense. But when this fails, our white blood cells kick into action. white blood cells are the cells of our immune system. There are two types of white blood cells- phagocytes and lymphocytes. Phagocytes have a multi lobed nucleus within the cytoplasm. They are made in your bone marrow, and they actively seek out to engulf bacteria. They will even squeeze out of the blood, through the capillary walls, to reach infected tissue. When they are on a charge, nothing stops these cells. They will often die loaded with bacteria that they have engulfed and killed. In boils and cuts, this is seen as yellow pus. There are different types of phagocytes, with neutrophils being the most common. Lymphocytes have a huge nucleus and just little cytoplasm. They are formed in lymph nodes, and are found all around the body, such as in your armpits and neck. Invading pathogens contain a chemical on their surface called antigens. The lymphocytes detect this and produce antibodies in response to it. The antibodies stick to the surface of the pathogen and kill it by either making it easier for phagocytes to ingest them, or making the pathogen burst, or making the pathogens clump together which turns them into a sticky mess and again makes it easier for phagocytes to find them. Each antibody is very specific; it will only attack one type of bacteria. Other lymphocytes produce antitoxins which combine with the invader’s toxins and make them harmless. Sometimes the body cannot produce antibodies naturally or fast enough, and so we can have vaccinations to help us out. we will look at vaccinations, they may only be 1% of our blood. but our white blood cells can really pack a punch. you just need to remember that phagocytes and gulf pathogens and lymphocytes produce antibodies and anti toxins.