The units of the body that we call cells
In viewsletter number 1, I described the body as a collection of groups of cells that work towards the goal of survival. In order to survive, the cells need to maintain the most suitable environment they can for themselves, given the circumstances at any particular time.
Each cell has many minute components inside itself, bathed in a liquid known as the intracellular fluid. The outer edge of each cell is defined by a wall or "membrane", which holds these internal features within its confines. The cell wall also separates the inner cell from its immediate environment, which is liquid bathing the cells known as the extracellular fluid.
To me, the cell membrane is the key to health, because the functioning of the cell is dependent upon what can pass across this barrier, both what can get into the cell and what can get out of it. Since collections of cells make up every part of the body, these membranes can be said to govern whether or not the proper functioning of each body part can occur.
Why do I look at it in this way? The health of the membrane can be said to regulate the nutrition that can enter the cell, and the toxic by-products from cellular actions that can leave the cell.
It follows, then, that understanding cell membranes, and their requirements for health, can help us in our quest to know more about how to look after the whole body. What can influence these walls can give us an idea of what can affect our health and wellbeing. All symptoms can be said to stem from the non-optimum state of cell walls, together with the consequent non-optimum condition of the intra-cellular and extra-cellular fluids on either side of them, and the changes in the body's biochemistry that this leads to.
What each body inherits can even be influenced by this, as the foetus cannot inherit a better biochemistry than that of its mother. It is, after all, bathed in it! Very many genes are switched on or off by such influences. The body can therefore show "inherited" conditions or not.
By the time we are forty years of age, it is said that 90% of the state of our body has been defined by our own diet and lifestyle, in other words what we have done to the body. However, this means that it is never too late to begin influencing the body for the better, because genes can be switched to healthier states with appropriate changes.
So, let us look at the cell membrane, or wall, in more detail. Firstly, it is living, with many reasons for being there, apart from the obvious one of defining the cell's boundaries and keeping its contents in place.
Basically, it is about transport. It is a barrier to prevent unwanted things from entering the cell and needed things from leaving the cell. It also has to do with the transport of substances across itself and the careful control of such passage, so that the cell can gain nourishment, as well as rid itself of toxic by-products from the cell's work.
Most of the nourishment that the cell needs dissolves in water and is called "water-soluble", whilst some dissolves in fat (lipid), and is called "fat-soluble" or "lipid-soluble". Fat and water do not mix, of course - a salad dressing made of vinegar and oil stays as two separate layers. When shaken before use, you can still see the tiny fat droplets in the vinegar. It is an unstable state that quickly returns to its separate layers
How does a cell membrane successfully deal with having to allow both fatty and watery substances through itself as needed, whilst still acting as a barrier for the watery cell fluid? The key to a cell membrane's adaptability with fats and water are substances called "phospholipids", which are fats with a metal named "phosphorous" attached to them.
These have an extraordinary composition in that one end of each unit likes to be next to something water soluble, whilst the other end likes to be next to something fatty. Each phospholipid unit looks like a tadpole with two tails. The "head" is attracted to water (hydrophilic), at the same time as the "tails" are repelled by water (hydrophobic).
Because of this, phospholipids can be comfortable with water on one side of them, and fat on the other. Both extra- & intra- cellular fluids are water soluble, so they attract the hydrophilic "heads". The cell wall is thus made from a double layer of phospholipids, with their fatty tails facing inwards, towards each other, making a water resistant layer, and the heads facing outwards.
The heads each have an electrical charge, which gives a charge to the outsides of the membrane. As such, it can attract water soluble proteins. Where these proteins penetrate right through the cell membrane, they form a path for watery substances to cross an otherwise fatty barrier.
These pathways can use the natural laws of physics to transport water-soluble substances, without the use of cellular energy, called "passive transport". Alternatively, energy can somehow be used to assist the passage, called "active" transport.
One other substance needs to be mentioned as a component of the cell wall and that is cholesterol, our own, "home-produced" body fat. This is scattered throughout the cell wall to give it flexibility. Without it, the wall would be too brittle, but with too much of it, the membrane would be too stiff for optimum movement at body temperature.