THE SKIN AND HOW TO LOOK AFTER IT
is a remarkable organ of the body which is able to perform various
vital functions. It can mould to different shapes, stretch and
harden, but can also feel a delicate touch, pain, pressure, hot and
cold, and is an effective communicator between the outside
environment and the brain.
Skin makes up to 12-15%
of an adult's body weight. Each square centimeter has 6 million
cells, 5,000 sensory points, 100 sweat glands and 15 sebaceous
glands. It consists of 3 layers: the epidermis (the outer layer), the
dermis ('true skin') and the subcutaneous (fat) layer.
is constantly being regenerated. A skin cell starts its life at the
lower layer of the skin (the basal layer of the dermis), which is
supplied with blood vessels and nerve ending. The cell migrates
upward for about two weeks until it reaches the bottom portion of the
epidermis, which is the outermost skin layer. The epidermis is not
supplied with blood vessels, but has nerve endings. Foe another 2
weeks, the cell undergoes a series of changes in the epidermis,
gradually flattening out and moving toward the surface. Then it dies
and is shed. Below is a detailed diagram of the skin
function of the epidermis is to form a tough barrier against
the outside world, while the dermis is a soft, thick cushion of
connective tissue that lies directly below the epidermis and largely
determines the way our skin looks. Both layers keep repairing and
renewing themselves throughout or life, but the dermis does it more
slowly than the epidermis. Under the dermis is a layer of fat cells,
which is know as adipose tissue (or subcutaneous fat layer). It
provides insulation and protective padding for the body. It also
provides an emergency energy supply.
epidermis consists of 5 layers:
Basal layer (Stratum germinativum) - this is the bottom
layer of the skin. The cells of this layer constantly been
reproduced, since they contain a nucleus, or seed. As the cells
reproduce, the layers get constantly pushed up into the next layer.
The prickle cell layer (Stratum spinosum) - called this
way because the cells have spines which prevent bacteria entering
the cells and moisture being lost. These cells also have a nucleus
and therefore reproduce.
Granular layer (Stratum granulosum) - the prickle cells
lose their spines and become flatter. The nucleus dies, and protein
is formed called keratin. This protein prevents moisture loss and is
found in skin, nails and hair.
Clear layer (Stratum lucidum) - this layer is for
cushioning and protection and is found only on the palms of the
hands and soles of the feet.
Horny (cornified) layer (Stratum corneum) - the cells
here are dead and ready to be shed (desquamation). This process
speeds up as we age.
dermis is the layer responsible for the skin's structural integrity,
elasticity and resilience. Wrinkles develop in the dermis. Therefore,
an anti-wrinkle treatment has a chance to succeed only if it can
reach the dermis. Typical collagen and elastin creams, for example,
never reach the dermis because collagen and elastin molecules are too
large to penetrate the epidermis. Hence, contrary to what some
manufacturers of such creams might claim, these creams have little
effect on skin wrinkles.
dermis is the middle layer of the skin located between the epidermis
and subcutaneous tissue. It is the thickest of the skin layers and
comprises a tight, sturdy mesh of collagen and elastin fibers. Both
collagen and elastin are critically important skin proteins: collagen
is responsible for the structural support and elastin for the
resilience of the skin. The key type of cells in the dermis is
fibroblasts, which synthesize collagen, elastin and other structural
molecules. The proper function of fibroblasts is highly important for
overall skin health.The dermis also contains capillaries
(tiny blood vessels) and lymph nodes which produce immune cells.
Blood capillaries are responsible for bringing oxygen and nutrients
to the skin and removing carbon dioxide and products of cell
metabolism (what we call waste matter). Lymph nodes are engaged in
protecting the skin from invading microorganisms.Finally, the
dermis contains sebaceous glands, sweat glands, hair follicles and a
small mumber of nerve and muscle cells. Sebaceous glands, based
around hair follicles, produce sebum, an oily protective substance
that lubricates the skin and hair and provides protection by forming
an acid mantle when mixed with sweat. When sebaceous gland produce
too little sebum, as is common in older people, the skin becomes
excessively dry and more prone to wrinkling. Too much of sebum, as is
common in teenagers, often leads to acne.
dermis is thicker than the epidermis, but has fewer cells. It
consists mainly of connective tissue which is made up of fibers of
the proteins collagen and elastin and a non-fibrous gelatin-like
material called ground substance or extracellular matrix.
tissue is the deepest layer of the skin located under the dermis and
consisting mainly of fat cells. It acts as a shock absorber and heat
insulator, protecting underlying tissues from cold and trauma. The
loss of subcutaneous tissue in later years, leads to facial sag and
makes wrinkles more visible. To counteract it, a cosmetic procedure
where fat is taken from elsewhere in the body and injected into
facial areas, is common these days.
are 6 skin functions:
- the nerve endings in the skin identify touch, heat, cold, pain and
regulation - the skin helps regulate the body temperature by
sweating to cool the body down when it overheats and shivering
creating 'goose bumps' when it is cold. Shivering closes the pores.
The tiny hair that stands on end traps warm air and thus helps keep
the body warm.
- absorption of ultraviolet rays from the sun helps to form vitamin
D in the body, which is vital for bone formation. Some creams,
essential oils and medicines (e.g. HRT, anti-smoking patches) can
also be absorbed through the skin into the blood stream.
- the skin protects the body from ultraviolet light - too much
of it is harmful to the body - by producing a pigment called
melanin. It also protects us from the invasion of bacteria and germs
by forming an acid mantle (formed by the skin sebum and sweat). This
barrier also prevents moisture loss.
- Waste products and toxins are eliminated from the body through
the sweat glands. It is a very important function which helps to
keep the body 'clean' from the inside.
- sebum and sweat are secreted onto the skin surface. The sebum
keeps the skin lubricated and soft, and the sweat combines with the
sebum to form an acid mantle which creates the right ρH balance
for the skin to fight off infection.