The Cardiovascular System
The circulatory system refers to the heart, blood vessels, and blood.
cardiovascular system, refers to the passages through which the blood flows:
- heart, a four-chambered muscular pump
- arteries, carry blood away from the heart;
- veins, carry blood
back to the heart;
- capillaries, connect the smallest arteries to the smallest veins.
The cardiovascular system has two major divisions:
1) pulmonary circuit, carries blood to lungs for gas exchange and returns to heart
2) systemic circuit, supplies blood to every organ of the body
The systemic circuit:
The left side heart serves the systemic circuit.Oxygenated blood leaves it by the aorta (sharp U-turn)
the aortic arch. The aortic arch supply the head, neck,and upper limbs. Then travels through the thoracic and abdominal cavities to other organs.
After circulating the deoxygenated blood returns to right side of heart by way large veins, the superior vena cava and inferior vena cava.
The pulmonary circuit:
The right side of heart receives circulated blood (unloaded oxygen) and It pumps it into pulmonary
trunk (right and left) then transport it to lungs, where carbon dioxide is unloaded and oxygen is picked up.The oxygen-rich blood then flows by the pulmonary veins to the left side of the heart.
Size, Shape, and Position of the Heart:
It is located in the thoracic cavity in the mediastinum, the area between the
lungs. About two-thirds of it lies to the left of the median plane .
The broad superior portion of the heart, called the base, is the point of attachment for the great vessels. Its inferior end, the apex, tilts to the left and tapers to a blunt point .
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