The cardiovascular system is composed of the heart, arteries, veins, capillaries and arterioles and venules. The heart is the main component. It is made of cardiac muscle, which is formed into a pump that is continually moving blood throughout the body. Blood is sent away from the heart along the arteries, arterioles, and capillaries and returns via the venules and veins.
The Main Line
The cardiovascular system is the main line of transportation throughout the human body. All nutrients, oxygen, hormones and even wastes and debris are transported from the origins to their destinations by the blood that flows through the vessels.
The Loop
The cardiovascular system is a continuing circuit, or loop. There is no beginning or end. If you use the heart as a starting point, blood travels from the heart, along the arteries, to the arterioles, to the capillaries, the venules, the veins and then back to the heart for the cycle to begin all over again.
Hypertension
Hypertension is one of the leading causes of cardiovascular disease. Hypertension results when the smaller arterioles offer increasing resistance against the blood that flows through them.
The Trade-off
Blood flows through the body as a transportation system. Blood cells carry oxygen or other nutrients to where they are needed throughout the body. If blood is carrying oxygen to a muscle in the body, it will carry that muscle's carbon dioxide waste back toward the heart so that it can be eliminated from the body.
Blockages
The cardiovascular system can become clogged with debris and plaque. When this occurs, the heart is deprived of needed oxygen and nutrients and a heart attack or stroke may result. This buildup is called atherosclerosis. Plaque builds up in the veins, and often it must be removed or circumvented through surgical procedures.
