In addition to showing human characteristics, skin also betrays our emotions.
Our faces redden when we are embarrassed or angry, and turn pale when we are
shocked. Skin also responds to outside stimuli, perceiving sensations of touch,
coldness, warmth, and pain. These sensations are each transmitted from the tips of
sensory nerves and are immediately translated into actions.
Skin is tough and elastic. Because of the abundance of fatty tissue at its lowest
layer and tough corneous tissue at its topmost layer, it protects the body with its
resistance to mechanical stimuli such as bruising, pressure, and friction. The
presence of a fatty membrane on the skin’s surface blocks permeation by water,
while its high acidity prevents germs from growing. When the skin is exposed to
sunlight, it turns red and pigments increase. This is the result of the ultraviolet rays
in sunlight, which are harmful when they penetrate the body excessively. As the
skin absorbs UV rays, the body is protected by the formation of the pigment
melanin. The skin is further the place where our immune system is built. This is
why a rash developed on the skin when we contract chicken pox or smallpox
confers a lifetime of immunity, and why inoculation prevents us from contracting
smallpox at all.
Skin includes sweat glands, which produce sweat, and sebaceous glands, which
produce oils. These are constantly being secreted onto the skin’s surface, giving it a
shiny appearance. Soluble substances typically are not absorbed by the skin, but can
be absorbed when dissolved in fat or alcohol. Permeation is particularly easy when
a substance has been emulsified with the addition of an emulsifying agent. The skin
is also a poor conductor of warmth, preventing external overheating and regulating
the radiation of warmth outside the body. Eighty percent of the heat radiated outside
the body comes from the skin, a process that occurs through heat conduction and
dissipation and through evaporation. Skin thus performs many important roles:
covering the body and protecting important internal organs, while expelling
moisture and salts to regulate and maintain a specific body temperature.
B. Wound Healing Effects
The skin completely loses its regeneration capabilities when the epidermis is
destroyed—for example, in the case of a burn severe enough to result in destruction
to the dermis. The results can sometimes be fatal. Even a less severe wound, if left
untreated, can form a keloid scar (a form of benign tumor caused by abnormal skin
growth resulting from a burn). More distressingly for some, the scars that result
from burning may last for a lifetime. Normally, the best way to treat these is by
autodermic grafting (removing skin from another part of the body for grafting).
Skin will not engraft unless it comes from the patient him or herself. No examples
of engrafting with non self skin have been found in the past except between
identical twins. Because of these limits on graftable skin, it has been the dream of
medical practitioners to develop bona fide artificial skin that is capable of skin
regeneration (Dai et al. 2011).
That dream has now become a reality thanks to chitin extracted from crab shells.
Typically, the following effects are required for wound dressings near artificial skin:
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8 Developing Functional Materials with Marine Organisms
Our faces redden when we are embarrassed or angry, and turn pale when we are
shocked. Skin also responds to outside stimuli, perceiving sensations of touch,
coldness, warmth, and pain. These sensations are each transmitted from the tips of
sensory nerves and are immediately translated into actions.
Skin is tough and elastic. Because of the abundance of fatty tissue at its lowest
layer and tough corneous tissue at its topmost layer, it protects the body with its
resistance to mechanical stimuli such as bruising, pressure, and friction. The
presence of a fatty membrane on the skin’s surface blocks permeation by water,
while its high acidity prevents germs from growing. When the skin is exposed to
sunlight, it turns red and pigments increase. This is the result of the ultraviolet rays
in sunlight, which are harmful when they penetrate the body excessively. As the
skin absorbs UV rays, the body is protected by the formation of the pigment
melanin. The skin is further the place where our immune system is built. This is
why a rash developed on the skin when we contract chicken pox or smallpox
confers a lifetime of immunity, and why inoculation prevents us from contracting
smallpox at all.
Skin includes sweat glands, which produce sweat, and sebaceous glands, which
produce oils. These are constantly being secreted onto the skin’s surface, giving it a
shiny appearance. Soluble substances typically are not absorbed by the skin, but can
be absorbed when dissolved in fat or alcohol. Permeation is particularly easy when
a substance has been emulsified with the addition of an emulsifying agent. The skin
is also a poor conductor of warmth, preventing external overheating and regulating
the radiation of warmth outside the body. Eighty percent of the heat radiated outside
the body comes from the skin, a process that occurs through heat conduction and
dissipation and through evaporation. Skin thus performs many important roles:
covering the body and protecting important internal organs, while expelling
moisture and salts to regulate and maintain a specific body temperature.
B. Wound Healing Effects
The skin completely loses its regeneration capabilities when the epidermis is
destroyed—for example, in the case of a burn severe enough to result in destruction
to the dermis. The results can sometimes be fatal. Even a less severe wound, if left
untreated, can form a keloid scar (a form of benign tumor caused by abnormal skin
growth resulting from a burn). More distressingly for some, the scars that result
from burning may last for a lifetime. Normally, the best way to treat these is by
autodermic grafting (removing skin from another part of the body for grafting).
Skin will not engraft unless it comes from the patient him or herself. No examples
of engrafting with non self skin have been found in the past except between
identical twins. Because of these limits on graftable skin, it has been the dream of
medical practitioners to develop bona fide artificial skin that is capable of skin
regeneration (Dai et al. 2011).
That dream has now become a reality thanks to chitin extracted from crab shells.
Typically, the following effects are required for wound dressings near artificial skin:
262
8 Developing Functional Materials with Marine Organisms