The Elusive Lymphatic system, what does it do?

Posted by on Apr 5, 2016 in Articles | 0 comments

Basically the lymphatic system (alongside the blood circulation) helps the circulation of fluids around the body on a large scale through the limbs and the trunk, with big vessels, down to the cellular level with tiny capillaries. That makes it sound like the system is a passive system of tubes but it is more sophisticated than that. At certain points in the system there are lymph nodes which do several things.

Lymph nodes as filtering stations:
The lymph nodes are where most of the action takes place and all the rubbish is filtered out of the tissue fluids. So any cell debris, old cells, tumour cells or any bacteria or viruses are pulled out.

Lymph nodes as lymph concentrators:
In the lymph nodes the lymph vessels and the veins are leaky and the local osmotic pressure forces some of the fluid into the blood so the lymph becomes thicker.

Lymph nodes and the immune system, fighting disease:
The lymph nodes are where most of the battles are fought against foreign ‘stuff’. It is the protein part of any bacteria, virus, tumour cell or any other foreign ‘stuff’ that is the ‘antigen’ (antigen is the name given to anything that stimulates an immune response). It is in the lymph nodes that antigens comes into contact with the immune cells and they become activated to fight the foreign body/disease.
NB How this happens and all the cells and chemicals involved is a huge area and quite complicated so I am going to do a separate article on this

Lymph nodes as a storage system:
Sometimes there are substances which are not easily eliminated physically like for example coal dust or some medical dyes, or cannot be neutralised as with some persistent viral or bacterial infections. These are then stored in lymph nodes and effectively closed off from the lymphatic circulation. In the case of infections they can lie dormant and contained by the lymph nodes and kept in check by the immune system. They may stay in this controlled state for life or re-emerge at a later time.