The
Hydrolipid Film
The skin surface is covered with what is called a hydrolipid
film - an emulsion of water (hydro) and fat (lipos). Its main
function is as an external barrier, a defence against bacteria
and fungi. In addition it keeps the skin supple.
In healthy skin the balance between oil and moisture is intact.
The hydrolipid film varies in quantity and composition according
to body region as well as exogenous and endogenous factors such
as the time of day, the season, air humidity or nutrition,
stress and illness.
Composition of the hydrolipid film
Analysis of the skin components and the keratinization process
shows that the following substances are found on the skin
surface:
sweat and
sebaceous oils
substances from the cornification process (protein
decomposition products) horny
cells still in the shedding process water
from the deepest layers that has reached the surface (transepidermal
water, insensible perspiration)
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These components form the skin's continuously renewed
protective film.
1 sweat
2 sebaceous oils
3 corneocytes, still in the shedding process
4 cornification process
5 transepidermal water |
Importance
of the hydrolipid films
One function of the hydrolipid film is to repel from invaders.
At the same time it maintains the suppleness of the skin. Due to
the presence of weakly acidic components such as lactic acid,
pyrrolidine carboxylic acid and amino acids, the hydrophilic
components of the hydrolipid film form a protective acid mantle.
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