Identify and explain the roles of the organs of the circulatory system. Explore the health of the human circulatory system.
The body needs a transport system to supply cells with the molecules they need for energy and growth. This transport system is called the circulatory system.
The circulatory system has three main roles: 1. Transport 2. Defence against disease 3. Homeostasis, including regulating body temperature.
Blood
Blood is a tissue made up of plasma and three types of blood cells – red blood cells, white blood cells and platelets.
z Fig. 8.3.1 The composition of blood Red blood cell White blood cells
Platelets Blood transfusions and blood types
People have different blood types, based on the different chemical markers on the surface of their red blood cells. The most well-known blood type system is the ABO system, which consists of A, B, AB and O blood types.
Do you know your blood type? What would happen if you received a blood transfusion of the wrong type? Would you consider becoming a blood donor?
