Lymphatic capillaries are tiny vessels that collect and filter fluid from your body’s cells and tissues. They help to maintain blood pressure and volume and prevent fluid buildup.
Lymphatic capillaries (CAP-uh-lair-eez), also called lymph capillaries, are tiny vessels that exist throughout your body. A capillary is a tiny tube with an inside diameter as thin as a hair.
Lymphatic capillaries are similar to blood capillaries, but they are larger in diameter and have closed ends. Unlike blood capillaries, fluid can flow into lymph capillaries but can’t flow out through the cell walls. It can only move forward.
Lymphatic capillaries belong to your lymphatic system. Your lymphatic system includes vessels, tissues and organs to collect extra fluid from nearly every organ in your body.
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Lymph capillaries help keep the overall fluid balance in your body. Throughout your body, interstitial fluid (fluid found in the spaces around cells) leaks from blood capillaries into your tissues. Lymph capillaries pick up this fluid and help return it to your circulatory system.
Lymph, also called lymphatic fluid, is the extra interstitial fluid that drains from your body’s cells and tissues. The fluid is watery and colorless.
Lymph includes substances such as:
Lymph capillaries have walls that only work one way, to let fluid in. As lymph capillaries collect interstitial fluid from tissues, the pressure in the lymph capillaries grows. This increasing pressure moves the lymph fluid forward toward the heart.
Everywhere in your body, your lymphatic capillaries collect lymph and move it into larger lymphatic vessels. Along the way, the lymph passes through lymph nodes, which filter and clean the lymph. Eventually, your body discards the waste and returns the filtered lymph to your bloodstream to begin the cycle again.
Here’s how the rest of the cycle works:
Returning this lymph to your bloodstream helps to:
Lymphatic capillaries have thin walls, only as thick as a single cell. The cells overlap each other so that interstitial fluid easily enters the capillaries.
Lymphatic capillaries are closed at one end. They contain a mini-valve that lets interstitial fluid flow into but not out of them.
Lymphatic capillaries consist of:
Lymph capillaries are found between cells (in the interstitial space). These capillaries are in the tissues of every organ in your body, except for your:
Conditions that affect the lymphatic capillaries include:
You can take care of your capillaries by:
It’s important to stay current with preventive care, including annual physical exams. That way, your healthcare provider can detect problems at an early stage.
Contact your healthcare provider if you experience symptoms including:
A note from Cleveland Clinic
Lymphatic capillaries are tiny vessels found in the tissues of most organs in your body. They transport and filter lymphatic fluid (lymph) from your body’s cells and tissues. Lymph capillaries help to keep consistent blood pressure and volume and prevent fluid buildup. Though several conditions can affect lymphatic capillaries, you can reduce your risk by living a healthy lifestyle and seeing your doctor regularly. Lymphedema is a chronic condition that most often requires non-surgical management.
Last reviewed by a Cleveland Clinic medical professional on 10/05/2021.
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