Download Layers of the Skin

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S The skin together with its accessory organs, sweat
glands, sebaceous glands, hair and the nails forms
the largest organ in the human body.
S This system covers 1.5-2m2 and represents 16% of
body weight.
S The skin and its accessory organs form the
integumentary system.
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S The human skin is composed of three major layers of tissue:
epidermis, dermis and subcutaneous layer.
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The epidermis is the top layer of skin made up of epithelial cells.
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The dermis is the middle layer of skin, composed of dense
irregular connective tissue such as collagen with elastin.
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The subcutaneous layer is the innermost layer, containing fatty
tissue
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S The epidermis main functions are protection, absorption of
nutrients and homeostasis. Also contains different types of
cells: keratinocytes, melanocytes, Merkel cells and Langerhans
cells.
S Accumulations of melanin are packaged in melanosomes.
These granules form a pigment shield against UV radiation.
S It does not contain blood vessels
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S The dermis is the middle layer of the skin that offers
elasticity. It is composed of connective tissues and collagen
fibers.
S The dermis provides a site for the hair follicles, sweat
glands, sebaceous glands, blood vessels, lymph vessels,
sensory receptors, nerve fibers and muscle fibers.
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S The subcutaneous is the layer of tissue directly underneath
the dermis. It is also called hypodermis.
S This layer of tissue is composed of fat cells and connective
tissue.
S Its functions include insulation, the storage of energy and
aiding in the anchoring of the skin.
S It is the thickest layer of the integumentary system
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S Protection
S Temperature regulation
S Sensations
S Storage of chemical compounds
S Excretion of wastes
S Synthesis of compounds
S Determines characteristics
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Stratum corneum
Stratum lucidum
Stratum
granulosum
Stratum
spinosum
Stratum
basale
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S Cutaneous
Pathology
(dermatopathology)
is
the
microscopic examination of skin biopsies in order to
determine a specific diagnosis or a list of differential
diagnoses.
S Usually the diagnosis can be determined by the routine stain
for tissue sections (Hematoxylin and Eosin).
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S The skin lesions which developed recently according to the
patient history should be selected for that purpose. Detailed
clinical information (age, sex and site of skin biopsy) of the
investigated patients should be provided.
S Biopsies from healthy donors may be analyzed for control
purposes in some cases.
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S Acne
is a very common skin
condition
characterized
by
comedones
(blackheads
and
whiteheads) and pus-filled spots
(pustules).
S It usually starts at puberty and
varies in severity from a few spots
on the face, back and chest, which
most adolescents.
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S A basal cell carcinoma (BCC) is
a type of skin cancer. There are
two main types of skin cancer:
melanoma and non-melanoma
skin cancer.
S BCC is a non-melanoma skin
cancer, and is the most common
type (> 80%) of all skin cancer.
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S The
words ‘dermatitis’ and
‘eczema’ are interchangeable
and mean the same thing.
S Dermatitis
means
an
inflammation of the skin. The
term ‘contact dermatitis’ is used
when this inflammation is
caused
by
contact
with
something in the environment.
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S Fungal infections of the nails are also
known as onychomycosis, as tinea
unguium, and as ringworm of the nails.
The fungi are usually those that cause
athlete’s foot – a common infection of the
skin of the feet.
S In athlete’s foot the fungi live in the
keratin that makes up the outer layer of
the skin, but they can also invade the hard
keratin of which nails are made. When
this happens, the result is a fungal
infection of a nail.
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Cutaneous malignant melanoma is a cancer of
the pigment cells of the skin. If it is treated
early, the outlook is usually good.
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Melanocytes sometimes grow together in
harmless groups or clusters, which are known
as moles. Most people have between 10 and
50 moles and often they are darker than the
surrounding skin.
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They can then invade the skin around them
and may also spread to other areas such as the
lymph nodes, liver and lungs.
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