Why is the lymphatic system important?By Linda Emslie on 21 June 2016
The lymphatic system comprises a series of vessels and nodes and contributes to two vital bodily functions: transportation and immunity. It performs these functions in close interaction with the circulatory system.
In the course of circulating blood to all parts of the body, the circulatory system loses some fluid via diffusion from the capillaries. This “leaked” fluid forms the interstitial fluid that bathes and nourishes our cells. The interstitial fluid is also where our cells dispose of metabolic waste.
Tiny lymph vessels take up this waste-laden interstitial fluid, where it becomes known as lymph. On its return journey to the circulatory system, lymph is filtered through many lymph nodes and is cleansed of all metabolic waste. In performing this clean-up operation, the lymphatic system contributes to:
- maintaining blood pressure and blood volume
- maintaining the correct concentration of proteins in the interstitial fluid
- enabling the diffusion of nutrients from red blood cells
- circulating nutrients, dietary lipids and lipid soluble vitamins such as A, D, E and K
The lymphatic system, and your immune system
As part of the body’s immunological defence, the lymphatic system provides a home for B-cell lymphocytes (produced in lymph nodes) as well as hosting predatory cells, such as phagocytes and macrophages which attack and destroy, or “eat” up foreign invaders such as toxins, viruses and bacteria.
Fluid entering the lymphatic system is literally on a one-way trip to the cleaners. Lymph vessels contain valves (similar to those found in our veins) to stop back-flow. As lymph moves deeper into the lymphatic system it passes through numerous lymph nodes. The design of these nodes slows the flow of lymph giving the mop-up crew – lymphocytes, macrophages and phagocytes – plenty of opportunity to clean up. When the fluid is fully filtered and sanitised it is “safe” to be returned to the blood and recirculated throughout the body, returning to the blood stream via the subclavian veins.
In doing the body’s “dirty work”, lymph nodes are constantly exposed to dangerous agents such as bacteria, toxins, viruses and even cancer cells. Sometimes the lymph nodes are overwhelmed and become swollen and tender to touch. This is what is happening if you’ve ever experienced swollen glands when you’ve had a sore throat or bad dose of ‘flu.
Unlike the circulatory system, the lymphatic system has no heart to pump fluid around. Instead the movement of lymph relies on:
- fluid pressure within body tissue
- contraction of surrounding muscles
- contraction of the smooth muscle in the lymph vessel
- pressure from the pulsation of nearby arteries
- negative pressure in the chest during breathing (particularly the in-breath)
Without a functioning lymphatic system the accumulation of waste by-products and other toxins would quickly leave the body vulnerable to ill-health and disease.
Staying well hydrated, getting regular exercise, eating nutritious food, receiving lymphatic drainage massage, and employing suitable stress management techniques can all help support the health of the lymphatic system, and are wonderful ways to look after the whole body.
Lymphatic system care
Want to learn about how to maintain a healthy lymphatic system? I've written an article on just that, have a look at How can I look after my lymphatic system for more information.