Sunday, June 25, 2017

The biologist: II. Human being: An individual or a society of cells.

Cells in our body as citizens in a country: Contrasts and similarities.    

Nature has been organised in units. As far as we know, each unit can be considered as a society of smaller units. So, a solar system can be seen as a society of a sun with its surrounding planets. But in turn the solar system itself can be seen as a unit in a star system (galaxy). On the other hand an atom closely resembles a solar system with its nucleus surrounded by electrons. However, as part of a molecule, it is as one of the many solar systems in a galaxy.

We are used to see our body as an entity, but it can also be seen as a society of cells. Each cell in turn can be seen as a society of molecules.
When we compare the cells in our body with citizens in a city or a country, remarkable similarities can be seen.
Cells are living among an infrastructure of collagen, reticulin fibres, bone, cartilage, blood and lymph vessels, intestinal tract, urinary system, nervous system and many other structures  prepared and populated by specialised colleagues of them. 
We live in a city with houses, buildings, road- and railway networks, sewer-systems, electricity-networks prepared and  manned by some of our specialised colleagues.
In both cases, the infrastructure has to be adapted regularly to a growing body or a growing city. Both the demolition and the rebuilding are performed by specialists. 
In our body e.g, bone is produced by osteoblasts, whereas osteoclasts are the cells involved in the demolition of bone. So we can grow up thanks to these hard working cells.
Medieval cities conserved for historical reasons, remind us to our continuously changing modern cities. Construction workers adapt our buildings, sewer-systems, road-networks and railways to the needs of modern times.
Cells are highly specialised with respect to their function. During transport of ingested food, a lot of  cells are successively involved in its digestion. Specialistic cells are taking care for the right degree of acidity, required for the optimal action of the enzymes produced by other cellular specialists. 
In earlier ages similar jobs in our cities were often performed by workers unified in guilds. Street names in the old cities remind often to the streets were specific people were performing their similar jobs.
Also cells in our body with a similar function are often living together in specific tissues or organs for reasons of efficacy.
Epithelial cells are produced close to the place where they will practise their function. This reminds me to my youth in a mining district, where male children of the miners, living close to their mines, were usually becoming miners too, like their fathers and grandfathers before them. In other organs such as the pancreas, both endocrine cells producing hormones such as insulin and exocrine cells producing enzymes for the digestion of food, are living, but both endocrine and exocrine cells live in their own district, comparable to "China towns" in western cities.
Other cells, e.g. monocytes produced in the bone marrow, emigrate from there to the blood circulation, where they remain for some time. Hereafter they enter one of the many tissues in our body and will maturate there to become a tissue macrophage, involved in host resistance and regulation of functions of non-phagocytic cells there. They may also become dendritic cells, involved in antigen presentation to cells of the lymphoid system. Their maturation on the place where they will  get their final job, might be considered a work-placement. However, in case of cells, a work-placement does not imply that other options remain open too. When the location has been chosen, a job there is obligatory. Stem cells form the only cell population for which all options remain open.
Just as different specialists in a city, working together to perform a complicated project, different cells can also cooperate. Especial in host-defence a lot of specialistic cells are working together. Dendritic cells, T-lymphocytes and B-lymphocytes, are closely collaborating to initiate an immune response to unwanted microbial intruders such as bacteria, yeasts or viruses. B-lymphocytes rapidly develop into plasma cells producing specific antibodies against such antigens. These gamma-globulin molecules with specific affinity for the antigen, subsequently stick to it, allowing the uptake and digestion by a macrophage. As in our human world, numerous specialised soldiers are subsequently trained in order to defeat their enemy if he will try a new attack.
In an earlier blog, I did already pay attention to macrophages, comparing them with  high-tech, self thinking, vacuum cleaners. 
The cells involved in host-defence reactions in our body remind to a military organisation, where infantrymen, artillery-men and scouts are working close together.
Unfortunately, a transplantation is seen by the government of the cells in our body as an unexpected and treacherous attack. It will subsequently mobilise all cells usually involved in host defence and will organise a coordinated resistance in order to beat off the enemy.  This causes problems for our human medical care.
As you would expect the government of the cells resides in our brain. Neurons and several other specialists there are keeping control over the complete city or country. They are not chosen by the cells during elections as our politicians, and can thus be considered as representing a dictatorial regime. On the other hand, contrary to some dictators that we - as men - have seen, these cellular rulers want to be the best for the citizens and are not completely crazy. Admitted, this does not apply to governments in the brains of all men. 
Also they are - evolutionary spoken - hardliners. As a consequence, euthanasia is not a question of willing or not-willing. A senescent erythrocyte (red blood cell) e.g, is not asked for his own will, but euthanasia is obligatory and immediately performed by a macrophage, based on changes in its surface molecules. These are recognised by the macrophage and judged as not efficacious for the cellular society as a whole. 
It reminds to fascist and communist practices in our human world. Of course euthanasia should never be obligatory for human beings. On the other hand, help for those with a long term wish for euthanasia as well as refusal of such help by physicians who have problems with euthanasia, should never be a reason for punishment in a civilised society as explained in an earlier blog (Euthanasia: A human right).
The government in our brain rules with the aid of the nervous and the neuroendocrine systems in our body. In turn these systems act partly via specialised hormone producing cells in several hormone producing centra. Other hormone producing cells are autonomous and respond directly to measurements on different locations in the city.
Whereas many cells in our body never leave their district or even their neighbourhood, other cells are regularly moving. Peripheral blood leukocytes e.g. move easily here and there between the various lymph nodes, spleen and other lymphoid structures distributed in our body. During their transport  in our body they use the blood circulation or the lymph flow as transport systems.
A final question to be answered is: Is there any information that cells in our body could become terrorists comparable to some human beings in a country? 
Yes, cancer cells in our body are comparable to radicalised men in human society. At the moment they are mostly Muslims. They do not have any problem with their own fate. They know that they will die themselves during their suicide attack, but they believe to be rewarded in their next life by a God. They do not understand that such a God would be the main enemy of all human beings, if he would really exist.
Though cancer cells try to establish their own state in our body and are rather successful in hiding themselves between normal cells, just as the terrorists of IS, they are not able to kill normal cells individually. Their ideal is to destroy the complete society of cells (our body).

Nico van Rooijen; Haarlem, June 26.

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