Lymph Vessels — Protection from Edema

Lymph vessels

The purpose of the lymph vessels in the human body are to remove lymph from the system. The vessels are part of the lymphatic system, which is ancillary to the cardiovascular system. The lymph vessels work together with the blood vessels to remove interstitial fluid from the tissues and also to transport certain molecules from the bloodstream to the lymph nodes in order to be purified.

What is the purpose?

The lymph vessels store plasma and other substances which have ended up leaking out of the vascular system. In addition to the above, they also transport cells and lymph fluid back to the circulatory system. If your lymph vessels are not functioning properly, lymph is unable to be drained from the body and swelling can result under the skin (also known as edema). This condition can be life threatening.

How are lymph vessels made up?

Lymph vessels
Lymph vessels’ capillary. Source: Wikipedia.org

In many ways, lymph vessels look like blood vessels. They have an inner layer which mechanically pushes along and transports fluid, however, it leaks easily because the surface of the vessels is porous. Smooth muscles are also layered around the lymph vessels which work automatically to help move the lymph fluid along.


The whole system is powered by a complex series of valves made out of endothelial cells with “button” junctions between them that allow liquid to pass through them. Fluid is drawn into the smallest of the lymph vessels, the capillaries, but if this is not efficient then they can swell up and edema can occur.

White blood cells

The lymphatic system also works together with the immune system. White blood cells, particularly the lymphocyte, are a very important part of the immune system of vertebrates. There are different types of lymphocytes that are transported throughout the bloodstream and the lymphatic system. There are natural killer cells, T cells and B cells and all of them have their role in fighting disease and removing unwanted molecules from the body.

The “secondary circulatory system”

The lymph vessels are part of what is known as the body’s “secondary circulatory

Lymph capillaries in the tissue spaces. Lymph vessels
Lymph capillaries in the tissue spaces. Source: Wikipedia.org

system”. Basically, with the help of the different types of white blood cells, cancers, fungi, viruses and bacteria are filtered out of the blood and into the lymphatic system where they are fought and destroyed by white blood cells. The body’s cells recognize these foreign enemies and will seek them out and destroy them.

The lymph capillaries drain fluid and use a complicated valve system to clean the fluid. It filters this fluid and sends the waste leftover to the circulatory system to be ejected from the kidneys. It also acts to clean up dead blood cells and other cells that do not belong in the body.

Additionally, the entire system also aids the delivery of nutrients, oxygen and hormones from the blood to the cells of each individual organ in the body.

Where does lymph come from?

The actual fluid starts its life as plasma, which is basically the liquid part of blood (the various blood cells and cholesterol make up the solids). As blood flows out of the heart it goes through a bed of capillaries and these drain some of the plasma that flow into the tissues. This fluid is what delivers nutrients, oxygen and hormones to individual cells.

While the bloodstream has the heart to pump it, the lymphatic system has no such device and instead lymph only flows upwards toward the neck with the aid of the complicated valve system. The lymph vessels transport lymph through the lymph nodes where it is filtered and cleaned throughout its journey through the body.

Description of lymph vessels

The lymph vessels are the transportation mechanism for lymph fluid, which assists the immune systems and circulatory systems in keeping foreign bodies out of the human system. Read on to find out more.

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