Cell Transport Models

We have looked at vesicles, cell behavior, and biological osmosis.    Basically, living organisms are composed of single or multiple cells.    From the “Fundamentals of Medical Physiology”,   we know that the cell is the smallest unit of life and  cells are the fundamental building block of all living things.    Cells take in nutrients to generate energy and expel waste and other products.  The bloodstream brings nutrients and transports  waste products from cells.   This model is fundamentally straightforward and understandable.   Complications  arise when we examine the details of this interchange.    Models developed to understand transport of large, small  and charged molecules lead to a complicated cellular membrane.  

From the study of osmosis, we know that small molecules can pass through a membrane but large molecules such as sugar cannot.   Because of this, others have developed specialized mechanisms to transport materials across the cell membrane.   This this creates an overwhelming complexity in the cell membrane.  

We developed the molecular theory of osmosis to show that transport across  a membrane moves from a high vapor pressure region to a lower vapor pressure region.  (vapor pressure is related to concentration and molecular activity.)   And, we showed that free molecules of a substance exist in both the solid and liquid phases.   With this model, the direction of flow across a membrane agrees with the vapor pressure gradient.  The problem of membrane pore size is problematic, however.   

Recently, we found the work of Dr. Gerald Pollack.   He suggests that we question our assumptions and he proposed that a fourth phase of water exists.   In addition to solid, liquid, and vapor the fourth phase is more like a gel.  He calls it an Exclusion Zone.   This EZ water excludes solutes, is charged, and exists at boundaries.  Perhaps this EZ water region is the cell boundary.     Our bodies  are 99% water.     Perhaps this EZ water  boundary allows both  large and small molecular transport simply due to natural equilibrium processes.    We note that this discussion does not account for ion channel models.

Perhaps an improved understanding of our amazing bodies must be based upon improved assumptions and simpler models. 

©   Larry Howlett     HTMD Engineering     2020

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