Within the body, a collection of blood, usually clotted and resulting from
hemorrhage, is called a hematoma.
The spleen, the liver, and large abdominal veins serve as blood reservoirs, which
can be mobilized to maintain the circulating blood volume. (para 10-16)
If an individual has lost whole blood by hemorrhaging, it is often necessary to
give transfusions of whole blood. Whole blood transfusions continue the functions of
the RBCs. When fluid but few formed elements have been lost, plasma or a plasma
substitute will often be used.
On the surfaces of RBCs, there are a number of substances called antigens.
The blood of other individuals may contain antibodies to these substances. The blood
of the recipient and the blood of the donor must be matched to avoid potentially fatal
reactions. Important systems of such antigens include the ABO system and the Rh
The lungs, liver, and heart have two blood supplies. Blood to be worked upon by
the organ is called functional blood. Blood for the usual exchange of materials between
An end artery is the sole supply of blood to an area of the body. End arteries are
most common in the brain and the heart. If an end artery is damaged and can no longer
supply blood to its corresponding area, the tissues of that area will die. (para 10-20c)
Cycles of blood circulation include the pulmonary cycle and the systemic cycle.
In the first of these, blood circulates from the heart to the lungs and back to the
heart. In the second, blood circulates from the heart to the rest of the body and back to
The primary motive force for driving the blood along the arteries is the heart,
Why is the wall of the left ventricle especially thick? It has to drive the blood
throughout the body.
The amount of blood forced out of each ventricle in one contraction is called the
stroke volume. The amount of blood pumped out of the ventricles in a minute is called