blood

• red blood cells carry oxygen from the lungs to the body cells and back
• red blood cells have no nucleus which means there is more space for oxygen to be absorbed
• red blood cells have a biconcave disc shape which provides a large surface area to absorb oxygen
• red blood cells consist of a pigment called haemoglobin
• haemoglobin binds with oxygen to form oxyhaemoglobin. the form remains until it reaches to respiring tissues, where it splits to release oxygen
• blood is tissue which consists of plasma that carries components such as red white blood cells platelets
• red blood cells carry blood from lungs to cells in the body
• white blood cells defend unwanted microorganisms from our immune system
• some white blood cells engulf microorganisms, some may produce antibodies to destroy them and others may produce antitoxins to neutralise the toxins produce by them
• white blood cells carry out the process also known as phagocytosis
• platelets are fragments of cells that help our blood clot. They are released from the bone marrow and prevent excessive bleeding and even unwanted microorganisms from entering.
• plasma is a liquid that carries many substances such as hormones, all blood cells, proteins, nutrients such as glucose and many more