Video Transcript
Which organs are involved in the
hepatic portal circulation pathway? (A) The lungs and the stomach. (B) The heart and the small
intestine. (C) The liver and the organs of the
digestive system. (D) The kidneys and the heart. Or (E) the heart and the organs of
the respiratory system.
Let’s begin by looking at the major
circulation pathways within the human circulatory system. You may remember that there are two
major circulation pathways in the body: the pulmonary circulation system and the
systemic circulation system. The functions of these two pathways
are indicated by their names. The word “pulmonary” refers to the
lungs. The pulmonary circulation system is
responsible for transporting deoxygenated blood from the heart to the lungs so that
it can be oxygenated and then back to the heart. The word “systemic,” on the other
hand, describes anything relating to the whole body. The systemic circulation pathway is
responsible for transporting oxygenated blood from the heart to almost all of the
organs of the body and then deoxygenated blood back to the heart.
This question asks us about a
different circulation pathway called the hepatic portal circulation pathway. Just like the other two, the name
of this pathway gives us a clue about its function. What do you think the word
“hepatic” means? The word “hepatic” derives from the
Greek term used to describe anything relating to the liver. The hepatic portal system is a
special circulatory pathway, shown here in green, that links the liver to the organs
of the digestive system. Let’s learn a little bit more about
why this pathway is so important.
The blood flowing away from most
organs of the body is delivered directly back to the heart through two large veins
called the superior and inferior vena cava. The organs of the digestive system,
however, are an exception to this rule. Before being delivered back to the
heart, the blood flowing away from the digestive system is first transported to the
liver through the hepatic portal vein. The liver is very important for
digestive and metabolic functions, like storing glucose and producing bile to help
break down fats. Furthermore, the liver is
responsible for detoxification, which is the conversion of toxic molecules into less
harmful ones.
In fact, the liver performs some of
the most crucial functions in the body. Because the functioning of the
liver is so important for survival, it requires a great deal of nourishment. This is one of the reasons why the
nutrient-rich blood from the digestive system is transported to the liver first. The blood flowing away from the
digestive system might also carry toxic substances that the liver needs to detoxify
before they enter the general bloodstream. Once blood has been processed in
the liver, it eventually flows into the inferior vena cava and then into the heart
to deliver nutrient-rich blood to the rest of the organs of the body.
We can now answer our question
correctly. We are asked to identify which
organs are involved in the hepatic portal circulation pathway. And the correct answer is (C), the
liver and the organs of the digestive system.