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CARDIOVASCULAR SYSTEM

• The cardiovascular system is made up of the heart and the various types of
blood vessels and lymph vessels.

• The principal functions of the cardiovascular system are:
• Transport of oxygen and nutrients to the tissues.
• Removal of carbon dioxide and other metabolic waste product from the

tissues.
• Plays a role in body temperature regulation.
• Distribution of hormones and immune cells throughout the body.
Basic structure of the cardiovascular system
• The wall of any blood or lymph vessels is made up of three layers or tunicae:
Tunica intima
• It is the innermost layer and consists of endothelium, subendothelium and

internal elastic lamina.
• The endothelium is a single layer of extremely flattened epithelial cell rest on a

basement membrane.
• The subendothelial layer is a delicate connective tissue layer contains collagen

fibers and sheets of elastin.
• The internal elastic lamina is a thin layer of elastic tissue separating the intima

from the media and is especially prominent in muscular arteries.
2. Tunica media
• It constitutes the middle layer and consists of concentric layers of smooth

muscle and elastic connective tissue. It is thick in arteries, thin in veins. It is
formed of smooth muscles in muscular arteries and elastic membranes in
elastic arteries.

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