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Pulmonary Circulation
After blood makes its trip around the body to deliver the oxygen it was carrying, it returns to the heart in a deoxygenated state. In order to become oxygen-rich again, blood has to travel through the lungs. Blood will come from the body into the right side of the heart, to the lungs, into the left side of the heart, and pumped out to the body again.
Review the path blood takes in the pulmonary circulation; recall the names of structures in bold type that have been covered in earlier lessons within this description.
1. Blood returns from the body into the right side of the heart via the superior and inferior vena cava.
2. As blood enters the right side of the heart, it first goes through the right atrium, and then to the right ventricle, and out through the pulmonary arteries to the lungs.
3. Blood returns from the lungs, oxygen-rich, through the pulmonary veins, and into the left atrium, then the left ventricle, and out to the body through the aorta.
Take a moment to view pulmonary circuit, illustrating the pulmonary circulatory system. Pay attention to the arrows showing blood flow direction and the names of the structures. Notice there a pulmonary arteries and veins on the right and left sides of the body. Also, recall that these are the exceptions to the type of blood normally carried through arteries (usually oxygen-rich) and veins (usually oxygen-depleted).
Systemic Circulation
This is the portion of the cardiovascular system that transports oxygenated blood away from the heart through the aorta from the left ventricle, and then it returns oxygen-depleted blood back to the heart.
Systemic circulation involves delivering blood to all organ systems except the pulmonary. Review the path of the systemic circulation.
1. Oxygen-rich blood exits the left ventricle of the heart into the aorta, and then out to the rest of the body delivering oxygen.
2. Blood travels through arteries, then arterioles, and into capillaries, returning through venules, and then into larger veins.
3. Blood finally enters the pulmonary circulation after returning to the heart via the superior and inferior vena cava.
Image 16 illustrates the blood vessels all over the body involved in the systemic circulation.
Check your understanding:
What is the main difference between pulmonary circulation and systemic circulation?
Answer: Pulmonary circulation involves the blood flow to the lungs for the purpose of replenishing oxygen while systemic circulation involves the delivery of the oxygenated blood to the body and back to the heart.
Which of the circulatory systems follows this path?
Right side of the heart to the lungs to the left side of heart
Answer: Pulmonary circulatory system
Complete this path:
Right atrium to right ventricle to _______ ______ to lungs to _______ _______ to left atrium to left ventricle
Answer: pulmonary arteries/pulmonary veins
