Welcome to part 1 of our series on the Lymphatic System, by the Vascular Anomalies Center here
at Children’s Hospital Colorado.
In this video we’ll explain what the Lymphatic System is, and click here or check the description
below for part 2 where we explore what happens when it doesn’t form correctly.
The Lymphatic System is an efficient, intricate, and vital organ system in your body.
But it is often poorly understood.
Our bodies have two main circulatory systems for transporting fluid, cells, nutrients and
waste: the Cardiovascular, or Blood System, and the Lymphatic System.
They are like two mass transit systems, with passengers, routes and destinations.
Both are made up of vessels, the train tracks and roadways, and passengers, the cells, molecules
and fluid.
These systems transport passengers from all over the body.
The Blood System is like a high-speed train, the “Non-Stop Express.”
It carries cells, like red blood cells, platelets and immune cells, and water, nutrients, and
other molecules.
The trains depart from the heart, the “Grand Central Station,” and branch off via smaller
and smaller vessels to destinations all over the body.
At each destination, trains drop off their passengers at the “capillaries,” the smallest
vessels in the body.
At some destinations, passengers get off and deliver nutrients and supplies.
At other locations, like the lungs, new passengers, like oxygen, hop on board.
Each train returns to the heart to be pumped out to the body again.
However, only 85% of the passengers riding the blood system get back on.
The other 15% are picked up by the Lymphatic System.
The Lymphatic System is like a high-tech taxi system, which helps several important systems:
the blood system, the immune system, and the digestive system.
First, the Lymphatic System returns extra fluid back to the blood system.
When passengers are picked up at the Lymphatic capillaries, they’re called “Lymph.”
Lymph is made up of proteins, fats, immune cells, and extra fluid that has leaked out
of the blood system, which needs to be returned.
These capillaries merge with lymphatic vessels, which join into larger trunks, and ducts,
which finally drain into the heart, returning the lymph to the Blood System.
This is the normal journey for fluid in the body: from the blood, to the tissues, some
to the lymphatics, and back to the blood.
Second, the Lymphatic System helps the immune system fight infection.
On its journey back to the heart, Lymph is stopped by many strategically placed checkpoints
for the Immune System, which helps your body fight infection.
These are called the "lymphatic organs."
They include your tonsils, adenoids, Peyer’s patches, hundreds of lymph nodes, and the
spleen, which acts like the largest lymph node in your body.
The thymus and bone marrow have important jobs as well.
At these checkpoints, immune cells look for threats.
If a threat is detected, the lymphatic organ calls for help, and extra lymph floods in,
carrying masses of immune cells.
The increased amount lymph causes the organ to swell up.
After the threat is eliminated, the swelling goes back down.
Finally, the Lymphatic System helps the digestive system.
At the small intestine, nutrients get on the blood system.
However, some nutrients, like fat, are too large to get on board, and are picked up by
the lymphatic system.
Since this lymph is rich in fat, it’s called “chyle.”
Chyle is affected by the kind of food you eat.
For example, a juicy steak makes the chyle much richer in fat and protein compared to
a salad.
Chyle travels up the central lymphatics, the main central highway of the lymphatic system,
up to the heart, enters the blood stream, and finally travels to the liver, where its
large, rich nutrients are digested.
Today you learned that the Lymphatic System is one of two circulatory systems, along with
the blood system.
It helps return extra fluid to the blood system, helps the immune system fight infection, and
helps transport fat and other large molecules for your digestive system.
But what happens when the Lymphatic System doesn’t form correctly?
Click here to check out our next video on Lymphatic Malformations, or check the description
below.