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Circulation of Lymph
The lymphatic system circulates lymph in an effort
1) to filter out cellular debris, pathogens and
2) to maintain fluid volume homeostasis.
As the blood travels through blood vessels, some of the plasma portion of the blood leaks through the capillary walls of the blood vessels through which it is traveling. This plasma becomes extra fluid ending up in the spaces between cells called interstitial spaces. The lymphatic system is responsible for returning this fluid back to the bloodstream. See Image 8 for an illustration of the components of blood, noting the plasma (the yellow liquid component making up 55% of blood) component.
image 8
In its return to the bloodstream, the extra fluid enters lymphatic capillaries that empty into larger lymphatic vessels (see Image 9 for an illustration of these capillaries).
image 9
This lymph travels through these vessels until it reaches the site where it empties into the blood at the subclavian veins (See Image 10 to identify that site).
image 10
The lymphatic system plays a major role in immunity and in fluid volume homeostasis the ability of the body or a cell to seek and maintain a condition of equilibrium or stability within its internal environment . Image 11 is an example of what can happen when the lymphatic system is not adequately returning interstitial fluid back to the bloodstream. You will notice the left leg swelling because of this condition. This is termed lymphedema.
Image 11
Check your understanding:
Where does lymph originate from?
What are 2 goals being accomplished as the lymphatic system circulates lymph?
Where is the site that lymph is carried back into the blood vessels?
