Skin
Structure
The Skin - Its
structure and function
The stratum germinativum
is composed of a single layer of cells.
These cells are very busy constantly reproducing
to form new cells, which move upward and
outward toward the skin’s surface. As each
new layer of cells form, it displaces the
overlying layer, therefore the three upper
layers are replaced every 28 days. This
continuous reproduction gives skin the ability
to heal well after injury, to peel after
sunburn and to rejuvenate each day with
proper care. This layer also reproduces
pigment granules called melanocytes; this
gives the skin its colour.
The stratum spinosum is
the next layer from where the epidermal
cells move from the stratum germinativum.
Because these cells have such a close connection
with that layer, they begin to die.
The stratum granulosum.
This layer consists of cells that are flattened
and look like distinct granules consisting
of keratin. These cells are dying and undergo
a change into a hard substance. Finally,
the skin cells complete their month-long
journey of migration to the skin’s surface.
The strata lucidium. This
layer consists of small, transparent cells
through which light can pass. Their function
is not really known, but it thought that
this layer acts as a barrier in some manner.
It is not present where there are hair follicles.
The stratum corneum. This
layer consists of tightly packed scale-like
cells that are continually being shed and
replaced. It also serves as a barrier and
protects the deeper layer of the skin and
body.
Sebaceous glands are found
in all part of the body, particularly the
face. Sebaceous glands produce a greasy
substance (sebum) from the breakdown of
the dead skin cells. This helps keep the
skin and hairs soft, flexible and waterproof.
Sebum flows through the oil ducts leading
to the mouths of the hair follicles, so,
when sebum becomes hardened the follicle
blocks, causing a blackhead to form. Sebum
helps to keep the skin greased and, after
puberty, acts as a mild anti-bacterial,
anti-fungal dressing. The sebaceous glands
are under hormonal control and are the focus
of the chemically induced inflammation occurring
as acne spots. Due to the way sebaceous
glands function, they contribute to the
acid mantle. Thus is the skin’s natural
protective barrier, which is a visible film
on the skin’s surface and which protects
it from harmful agents entering, such as
bacteria and environmental pollutants.
Collagen is one of the
chemicals that help bind the constituents
of the dermis together. Elastin is responsible
for the elasticity in the dermis. In the
papillary upper dermis. Collagen forms a
loose network of thin fibres that are parallel
to the wavy ridges of the overlying epidermis.
In the reticular deeper dermis, the collagen
fibres are thicker and the network of interconnecting
fibres is denser and lies parallel to the
skin. The elastin fibres are interwoven
between the strands of collagen; this makes
the dermis pliable and recticulum fibres
add support. Collagen allows for stretching
and contraction of the skin provides strength
and aids in healing wounds. The elastic
fibres allow the skin to stretch. Skin elasticity
is what permits the skin to spring back
to normal after weight gain and permits
us to smile and make facial expressions.
Healthy skin beauty brings you the latest in healthy skin products and information
. (c) 2008 - Angie
Beale enterprises pty ltd |
