Video Transcript
What are the two major pathways of
blood circulation through the human body?
To answer this question, let’s
review the main pathways of blood circulation and the key functions that the
circulatory system performs.
The human circulatory system is
composed of a heart, which functions as a central pump to keep blood flowing to and
from the various organs of the body, and a complex network of blood vessels, which
here we have simplified into the two major circulation pathways. Let’s review the roles of these two
pathways so that we can answer this question correctly.
The word “systemic” refers to the
whole body. The systemic circulation pathway is
responsible for delivering oxygenated blood from the heart to the brain, liver,
intestines, and almost all of the other organs in the body. Oxygen is taken up from the blood
by the cells of the organs, and the blood collects their carbon dioxide and waste
products. This blood is now said to be
deoxygenated and is carried back to the heart. So where does the blood get the
oxygen it needs to deliver to these organs? And what happens to the carbon
dioxide in deoxygenated blood?
Well, this is the function of the
pulmonary circulation pathway. This pathway carries deoxygenated
blood from the heart to the lungs. This is easy to remember, as the
word “pulmonary” refers to the lungs. The carbon dioxide in the
deoxygenated blood is exhaled from the body via the lungs. And the oxygen that enters the
lungs from atmospheric air diffuses into the blood. This oxygenated blood is carried
back to the heart, ready to be pumped through the systemic circulation pathway.
Now that we have reviewed the two
components of the circulatory system, we can answer our question correctly. The two major pathways of blood
circulation through the human body are the pulmonary and systemic circulations.
