blood

• red blood cells: carry oxygen from the lungs to the body cells

  -have a biconcave shape to maximise surface area

  -dont have a nucleus
• white blood cells: defend against infection by:

  -phagocytosis

  -producing antibodies that bind to antigens on pathogens and engulf them

  -producing antitoxins which neutralise any toxins

  -also have a nucleus
• platelets: involved in clotting
• platelets: small fragments of cells that float in the blood and help blood clot and form scabs
• plasma: liquid portion of blood that contains dissolved substances and cells
• blood plasma: carries nutrients, hormones, waste products, gases (oxygen) and proteins around the body
• in the case of blood loss: we can add artificial blood, salt water to add volume and transport oxygen to all the cells or we can use a blood transfusion