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All About Blood
Fast Facts About Blood
• The average human body contains approximately six quarts
(5.7 liters) of blood.
• In one day, blood travels nearly 12,000 miles (19,312 kilome-
ters).
• A human heart beats about 35 million times a year, pushing
blood through the body’s vessels.
different types of blood spatter tell different tales about the crime. But how
do investigators and forensic experts know the differences? It begins with
a thorough understanding of blood and human anatomy.
Characteristics of Blood
The popular saying goes: blood is thicker than water. This is very true. Many
different types of molecules, each with a specific job, make up blood, so blood
is a very thick liquid because of this mixture of components. The various cells
themselves are not liquid; they are actually solids suspended in a liquid called
plasma—the clear fluid that gives blood its liquid character. In humans, about
55 percent of the volume of blood is plasma. The red blood cells are the part
of blood that gives it a reddish color. Blood also contains white blood cells and
platelets
, which are necessary for a person to be healthy.
Blood behaves in a unique fashion when it drips, gushes, or squirts on
different surfaces. When blood is discovered at a crime scene, an analysis
of the spatter patterns can reveal a surprising amount of information about
