42- the Reticuloendothelial System

KYJ42- Reticuloendothelial system.

If you are one of those nurses who learned stuff once upon a time for exams, then forgot most of it, then we are probably kindred spirits.

The numbers of times I have learned, forgotten and relearned stuff is astounding, so you are not alone.

I once learned, forgot and relearned about the Reticuloendothelial System (RES) and thought I would do a simple KYJ on it.

Let's start by saying it is no longer called the Reticuloendothelial system any more.  The new name is the Mononuclear Phagocyte System (MPS).

The new name is helpful, because it offers an inkling into its function.
The MPS is part of our greater immune system. It is responsible for removing dead and dying cells and debris resulting from an immune response and programmed cell deaths (apoptosis).  For an example. A few posts ago we spoke about bilirubin and it's precursor being the natural death of Red Blood Cells. The MPS has s role in the mopping up of this cell debris.

Reflecting on our greater immune system we can use the analogy of a cake.

The cake is made up of many ingredients. So too is our immune system.
Consisting of proteins in plasma (antibodies and complement proteins), and white blood cells (macrophages, monocytes, basophils, mast cells, lymphocytes, eosinophils, phagocytes, neutrophils)

These ingredients all bring a different function to the fight against disease, cell death, pathogens, and allergens.

That part of our immune system that physically digests the foreign and dead cells.  Is what we formerly called the Reticuloendothelial system.

Specifically monocytes.
These cells are types of white blood cell (leukocyte).  Their role is uniquely different to lymphocytes and granulocytes.  Where lymphocytes manufacture chemicals to kill nasties, but monocytes actually engulf and digest particles like "The Pacman".  Monocytes, are the largest of all the white blood cells and it is perhaps surprising to note that more than half of all the monocytes live in the spleen.  Monocytes have an innate ability to migrate out of the blood stream and into tissues. They do this in response to chemical signals released by damaged or infected tissues.  When they migrate to the site of infection they change form and become macrophages- a type of phagocyte (phago= to eat, cyte=cell).

Macrophages are the largest of the phagocytes, and are thus named- macro=big, phage=eater.