Circulatory system: Blood vessels Laid end-to-end, an adult's arteries, veins and capillaries would stretch for about 100,000 miles - enough to wrap around the world nearly four times.

That means that the vans are very busy indeed, all the time. So it's a good job we've got the circulatory system to transport nutrients, water and oxygen to the entire body. Your circulatory ...

Veins between two capillary networks are portal systems. Closed circulatory system, but fluid constituents of blood leak out of capillaries and return to the heart by the second component of the ...