CK-12 Foundation
Ck 12: Biology: Blood
[Free Registration/Login may be required to access all resource tools.] Defines and describes red blood cells and white blood cells, and describes the roles of platelets.
Texas Heart Institute
Texas Heart Institute: Heart Information Center: Blood
Answers questions about blood: what it is, its function, and types.
Other
World Invisible: The Human Circulatory System: Blood Circulation
A labeled diagram of the major veins and arteries in the human body.
BBC
Bbc: Gcse Bitesize: Cellular Respiration and Transport
The circulatory system transports substances between the exchange surface and cells. It delivers oxygen and glucose to the tissues for respiration, which is the release of energy to cells.