Video Transcript
The diagram provided shows a
simplified view of the different circulatory pathways in the human body. Which color line represents the
systemic circulatory system?
We can distinguish three different
circulatory systems in the human body: the systemic system, the pulmonary system,
and the hepatic portal system. The word hepatic is used to
describe anything relating to the liver. And the hepatic portal system forms
a special connection between the digestive system and the liver. Unlike the blood from the other
organs of the body, the blood being transported away from the organs of the
digestive system is not collected by the vena cava straight away but is instead
transported to the liver.
The blood transported away from the
digestive system contains nutrients, like glucose and amino acids, which are
absorbed by the digestive organs. As the liver has so many crucial
functions to perform, it needs a substantial supply of these nutrients, provided by
the hepatic portal system, which directs the nutrient-rich blood from the digestive
system to the liver.
Aside from supplying the liver with
the nutrients it needs, the hepatic portal system also delivers blood from the
digestive system that might contain toxic molecules absorbed by the digestive
organs. These could be derived from
substances like ethanol or certain medications a person might take. And the hepatic portal system
ensures that these molecules are transported in the bloodstream to the liver, where
the blood is detoxified.
The red line on the diagram
provided by the question represents the hepatic portal system, as it shows the blood
flow from the digestive system to the liver.
The word pulmonary is used to
describe anything relating to the lungs. In the pulmonary system, the heart
pumps deoxygenated blood to the lungs, where it releases carbon dioxide into the
lungs and takes up inhaled oxygen. The oxygenated blood is then sent
back to the heart and pumped to the body. As the green lines on the diagram
show a representation of blood flow from the heart to the lungs and back, these
green lines represent the pulmonary system.
The word systemic is used to
describe anything relating to the entire body. The black lines represent the
transport of blood from the heart to the other organs in the body, including the
brain, and then back to the heart. This is the function of the
systemic system.
Now we can answer the question
correctly. The color of the line that
represents the systemic circulatory system is black.
