A consideration of mammalian dermal evolution.
Posted by Footy, on 2 August 2014
Hello everyone.
My background is in systems engineering, and i have over forty years experience of building and trouble shooting mechanical/hydraulic systems. I have an interest in the evolution and function of biological systems, hence my involvement in this. I have no issues with the genetic basis of biology, but i am pretty sure that genes cannot produce structures that can defy the laws of physics! There are physical laws that any system has to take account of, and that can also be taken advantage of in the function of the system. In my opinion the structures ultimately created by genetics, have evolved to take advantage of such physical laws. The example described here can be demonstrated in modern humans, and has wider implications in gender related physiology.
There is a physical connection in the mammalian dermal system, that has not been factored into certain dermal changes. This involves the mammalian hair cycle. There are many references to this disintegration and re-enlargement of the hair follicle “pocket” within the dermal tissue. The ongoing mystery of this is how cycle by cycle, the resulting follicle can change size so changing the amount of hair produced?
What is not refered to in any of the literature, is the natural resistence of the dermal tissue to such an enlargement of a pocket within it? Two things cannot occupy the same space at the same time. A hollow pocket in particular, is going to be very sensitive to external pressure. I suggest once you consider this basic physical connection, the mystery begins to clear.
Given recognised dermal physiology, the implication is that the hair producing structure evolved as a re-cycling pocket to use the prevailing resistence of the surrounding tissue. This is the most simple way to integrate hair production with the primary temperature response in mammals. The variable resistence of dermal tissue effects the follicle size, through the normal spacial restrictions upon tissue growth described here:
http://www.pnas.org/content/early/2014/03/26/1323016111
There are other advantages in evolution for the pocket based structure of the hair producing unit in mammals. More details are given in my basic outline article here:
This includes examples in modern humans, of the principles involved in this dermal resistence factor. I suggest people try out the eyebrow test described for themselves. There is much that can be added to this basic outline article. This just intends to describes the basics, and my thoughts on the wider implications.
One important implication, is that a particular androgen significantly increases lymphatic drainage efficiency. This represents a gender difference that has not been previously considered, but would fit very well with the known gender differences in immune function. This could shed an important light upon female susceptibility to autoimmune disease, and i am trying to promote the testing of this question.
Regards.
Stephen Foote.
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Just to clarify a point in my post above, about the testing of the predicted gender difference in lymphatic drainage efficiency.
Obviously because of my personal position, i cannot possibly organise or conduct such testing myself. I think most would agree that such a proven gender difference, and the identification of the cause of this would be important. I am therefore hoping to involve professional scientists in achieving this testing.
I am open to any suggestions about the technicalities of testing this, and i would like to propose the following test based upon the previous gender related study of lymphatic function below.
“Quantification of the initial lymphatic network in normal human forearm skin using fluorescence microlymphography and stereological methods”. Link to abstract: http://www.ncbi.nlm.nih.gov/pubmed/9327386
This is a particularly relevant study to this question, as it unexpectedly discovered significant gender differences in three of the four lymphatic parameters measured. Women demonstrating lower values than men.
The androgen implicated here is Dihydrotestosterone (DHT). A medical cream containing DHT is available as Androstanolone, brand name Andractim. I think the prior use of Andractim by some women in the testing area, would be a fair test in a repeat of the study above. If it is DHT that is causing these noted differences in gender lymphatic function, women treated should demonstrate a significant shift towards the male measured values.
These are my thoughts on such testing, and i would welcome any constructive input.
Regards.
Stephen Foote.