Circulatory System: Your Body
On average, your body has about 5 liters of blood continually traveling through it by way of the circulatory system.
[http://sln.fi.edu/]
Circulatory System: Human Body
The Cornwallis School in Kent have produced some excellent notes for their Year 8 and 9 pupils (12-15 years) on the blood system, breathing and respiration and bones and muscles.
[http://www.cornwallis.kent.sch.uk/]
Circulatory System: Human Body
Hear how each organ of the body works, how to keep it healthy and what can go wrong, on this site from the BBC. The audio material was originally broadcast on BBC World Service.
[http://www.bbc.co.uk/]
Circulatory System: Your Body
On average, your body has about 5 liters of blood continually traveling through it by way of the circulatory system.
[http://sln.fi.edu/]
Circulatory System: Heart An Online Exploration
From the moment it begins beating until the moment it stops, the human heart works tirelessly. In an average lifetime, the heart beats more than two and a half billion times, without ever pausing to rest. Like a pumping machine, the heart provides the power needed for life.
[http://sln.fi.edu/]
Circulatory System: LifeBlood An Introduction to Blood
The average adult has about five liters of blood living inside of their body, coursing through their vessels, delivering essential elements, and removing harmful wastes. Without blood, the human body would stop working.
[http://sln2.fi.edu/]