How does our lymphatic system function?

DW (English)

Our cardiovascular system has a great partner in the lymphatic system. It does indispensable work for our immune system and cleans up between the cells.

Transcript

00:00The human body is made up of trillions of cells, and there's a lot going on, not just

00:06in them, but in the spaces in between. That's where the bloodstream delivers nutrients and

00:11collects waste products. It's a neighbourhood where pathogens lurk and are pursued by immune

00:17system agents. The area is also littered with the debris of dead cells, and that's where

00:23the lymphatic system comes into the picture. At first glance, lymph might look inconspicuous,

00:29but in fact, behind its façade, the body's secret service is hard at work. Unlike the

00:36bloodstream, the lymphatic system has no pump, and it only travels in one direction. Its

00:42network extends to practically every corner of the body, and with help from muscles and

00:47valves, the system moves approximately two litres of lymph through its branching system every

00:53day. In the gut, fats that are too large for the blood vessels are absorbed by the lymphatic

00:59system. The tonsils trap pathogens from the air we breathe and the food we eat. And through

01:09the spleen, the lymphatic system cleans the blood, fishing out stuff that doesn't belong

01:13there. Around the vena cava, the system feeds filtered lymphatic fluid back into the bloodstream.

01:22There are hundreds of checkpoints throughout the body. The lymph nodes. There, agents from

01:29the immune system await. The B and T cells keep an eye on everything that's happening in

01:34the body. T cells have to graduate from a tough school, the thymus. This specialised organ

01:41is mostly active before birth and during childhood. It's responsible for the development of the acquired

01:47immune system. In the thymus, T cells learn what belongs in the body and what doesn't. They

01:55also train to recognise and fight infected cells. The selection process is rigorous. In

02:03the end, less than 5% graduate. But the system creates a highly specialised elite core of agents

02:11for the immune system that are able to detect and fight off millions of pathogens. When T cells

02:21detect interlopers, they call for backup. Then the lymph nodes can fill up and start to swell.

02:34Since an infection is under control, most of the immune cells and antibodies die off. However,

02:40some B and T cells remain behind. When the next attack arrives, they know what's coming and can

02:47quickly neutralise the invaders. And that is why you can acquire long-term immunity to certain diseases.

02:56Throughout your life, your lymphatic system quietly goes about its job.

03:01Balancing fluid, cleaning up the spaces between the cells, and keeping the immune system on its toes.

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