Re: What is the surface-area of the human skin?

Valentin:  These kind of questions are difficult to answer due in part to 
the differences in the size of individuals and the statistical ways by 
which such measurements are made.  Obviously, no one actually counts each 
cell!!  The number that I most often see for the surface area of the skin 
is 7600 square cm. or over 3000 square inches.  The thickness varies also 
from about 6 mm. on the soles and palms to about 0.5 mm. on the eyelids.  
In order to "count" the cells, and since you mentioned epithelium, I assume 
you are only talking about the epidermis, you would have to know the number 
of cells in thickness in each epidermal layer and then multiply by the 
total surface area.  Here are the numbers that are most commonly mentioned: 
 Stratum corneum  25 or more layers of dead cells; Stratum lucidum 3-5 
layers of dead cells but these are only in thick skin; Stratum granulosum 
2-5 layers; Stratum spinosum 8-10 layers; and Stratum basale 1 layer of 
highly reproductive columnar cells.  As you can see, any total number of 
cells would be a very rough approximation and I'm not sure of what value 
the number would be.  It is interesting to note that the basale cells 
migrate to the surface (corneum) about every 2 weeks and then slough off in 
about another 2 weeks.  Therefore, what ever the number of cells, we have a 
completely new epidermis every 4 weeks.  Now that is interesting!!  I hope 
my answer helps.  J. Bridger