Circulatory System (Human): Components
The circulatory system carries blood around the body,
supplying cells with oxygen and nutrients and removing
waste products. The main components are the heart (a
muscular pump) and a network of tubes (arteries, veins,
and capillaries) to carry the blood.
Main Components
Structure
Function
Heart
a muscular pump that
sits between the lungs
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Pumps blood around the body; and
valves within the heart control the flow of blood.
Arteries
blood-carrying tubes
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Transport blood from the heart to body tissues.
Arterioles (tiny arteries)
blood-carrying tubes
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Regulate blood supply to capillaries.
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Exchange substances with nearby tissues via capillary cell walls.
Venules (tiny veins)
blood-carrying tubes
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Take blood from capillaries.
Veins
blood-carrying tubes
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Transport blood to the heart from body tissues.
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Delivers oxygen, hormones, and nutrients to cells;
removes waste products from cells; and
some blood cells help fight disease.
Capillaries
minute tubes linking
arterioles with venules
Blood
a fluid containing plasma,
erythrocytes (red cells),
leukocytes (white cells), and
thrombocytes (platelets)
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Associated components
Bone marrow
A tissue in bone that produces erythrocytes and
leukocytes called granulocytes and monocytes.
Spleen
An organ that stores and releases erythrocytes,
eliminates damaged erythrocytes, and produces
lymphocytes (cells that produce antibodies).
© Diagram Visual Information Ltd.
Lymphatic system
This is a drainage system. Blind-ended tubes run
parallel to veins and arteries and carry lymph, a fluid
similar to blood plasma, from tissues, returning it to
the circulatory system. Some lymph vessels contain
enlargements called lymph nodes, whose cells
remove bacteria and help with the immune response.