SOLUTIONS TO EXERCISES, LESSON 9
The four basic components of any circulatory system are a vehicle, conduits, a
motive force, and exchange areas. The vehicle is the substance which actually
carries the materials being transported. A conduit is a channel, pipe, or tube
through which a vehicle travels. If we say that a force is motive, we mean that it
produces movement. Systems providing a motive force are often known as
pumps. Exchange areas exist so that materials being transported may be
eventually exchanged with a part of the body. (para 9-2)
The human cardiovascular system is a collection of interacting structures designed
to supply oxygen and nutrients to living cells and to remove carbon dioxide and
other wastes. Its four major components are the blood, blood vessels, heart, and
capillaries. The vehicle is the blood. The conduits are the blood vessels. The
primary motive force is provided by the heart. The exchange areas are provided
The major subdivisions of blood are the plasma and the formed elements. Plasma
makes up about 55 percent of the total blood volume. Plasma is mainly composed
of water. Among the most important materials dissolved in plasma are proteins.
After the blood clots, the clear fluid remaining is serum, which does not contain the
proteins used for clotting. Otherwise, it is very similar to plasma. (para 9-5)
The formed elements of the blood make up about 45 percent of the total blood
volume. While red blood cells and white blood cells are cells, the platelets are
only fragments of cells. What is the shape of an RBC? Biconcave disc. In a cubic
millimeter of normal blood, there are about 5,000,000 RBCs. RBCs contain a
protein called hemoglobin, which transports most of the oxygen carried by the
The most common types of white blood cells are neutrophils and lymphocytes.
Neutrophils phagocytize foreign particles and organisms. Lymphocytes produce
antibodies. In a cubic millimeter of normal adult blood, there are about 5,000 to
The main function of platelets is to aid in clotting by clumping together and by
releasing chemical factors related to clotting. In a cubic millimeter of normal blood,
Four general functions of blood are:
Serving as a vehicle.
Aiding in temperature control.
Protecting our bodies by providing immunity.