Anatomy of the skin
Aims and objectives
• To understand the underlying structures of the
skin
• To gain a basic understanding of the process of
wound healing.
• To be able to identify different tissue types in
areas such as the wound bed, wound edge
and surrounding skin
Anatomy of the skin
Is it important to know the
Structure and functions of the
skin?
• How many layers does the skin consist
of?
• Largest and most visible organ
• Made up of two main layers:
Epidermis – very thin layer and is
firmly attached to the dermis at
the dermo- epidermal junction.
Dermis- made up of two layers
comprising of fibrous proteins,
collagen and elastin which give
skin its strength and elasticity.
Below dermis is subcutaneous layer ,
this provides support to the dermis
and stores fat which protects the
internal structures.
• Does the skin vary in depth?
• Thinnest over eyelids -O.1mm
• Thickest over palms and soles of the feet –
1mm
The skin is the largest organ of the body it
weighs between 6-8 1bs
It has a surface area of 20 square feet.
What are the functions of the
skin?
• Protection of internal structures –
physical barrier to microorganisms
and foreign matter.
• Acid PH helps to prevent infection
• Sensory perceptionAllows you to feel pain,
pressure heat this helps
us to identify potential
dangers and avoid injury
• ThermoregulationBlood vessels constrict
or dilate to raise or
lower body
temperature. Sweat
production promotes
cooling
• Excretion –
Transmits small amounts
of water and body waste
via sweat
Helps to prevent
dehydration.
• Metabolism-Photochemical
reaction in the skin produces
Vitamin D essential for
metabolism of calcium
• Absorption-Some substances can
be absorbed directly into blood
stream
• Communication
Functions of the skin that declines
with age.
• Flattening of the dermal-epidermal junction, increased
susceptibility to friction/ shearing forces resulting in blistering.
• Decreased sensitivity to pain perception
• Epidermis becomes thinner and flatter , uneven distribution
of melanocytes leading to uneven pigmentation.
• Skin becomes wrinkled due to depletion of elastic fibres.
• Skin becomes dry as a result of atrophy of sebaceous glands
Baraboski (2003) and Beldon (2006)
How do wounds heal?
Classification of wound healing
• Wounds that heal by
primary intention e.g.
incisional wounds
• Wounds that heal by
secondary intention e.g.
pressure ulcers
• Wounds that heal by
tertiary intention e.g.
delayed suture
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• Wounds characterised by whether they are
acute or chronic
Acute wounds
Characterised by:
• No underlying aetiology i.e. trauma
• Short duration
• Normal inflammatory phase
• Heal and do not breakdown
21
Chronic wounds
Characterised by:
• Underlying pathology e.g. venous
insufficiency
• Prolonged duration
• Hyperactive state
• Persistent state of inflammation
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• Wounds go through 4 distinct phases
Normal Wound Healing Response
Proteoglycans
Neutrophils
Fibroblasts
Collagen
remodelling
Collagen
Scar maturation
Angiogenesis
MATURATION
Macrophages
Platelets
Lymphocytes
Fibrin
PROLIFERATION
INFLAMMATION
HAEMOSTASIS
MINUTES
DAYS
WEEKS
MONTHS / YEARS(whru)
Haemostasis
•Starts immediately after injury.
•Blood vessel contraction
(vasoconstriction)
Inflammatory phase
•Occurs between 0-3 days
Proliferation
•0-24 days
Maturation
•20 days – 2 years
•Closure of wound and re-epithelisation.
•Scar maturation
What factors may affect wound
healing?
Factors Affecting Healing
Systemic
•Age
•Anaemia
•Nutrition
• Medications e.g.: Anti inflammatory, Cytotoxic drugs, steroids
•Chronic health conditions eg :Diabetes Mellitus
•Systemic infection (Bowler & Davies, 1999)
•Oxygenation
•Smoking
•Psychological factors
•Temperature
Factors affecting healing
Local Factors
•Blood supply
•Denervation
•Haematoma
•Local Infection
•Duration
•Wound bed condition
•Anatomical site
•Size of wound
• Assessment of a wound is the responsibility of
the qualified member of staff
• You should ensure that this has been
undertaken and a treatment plan has been
established.
Remember
The selection of dressings or bandages without
accurately undertaking a wound assessment
taking into account underlying factors that
may delay wound healing may result in costly
treatments that are inappropriate and are not
successful!
Clinical appearance of wound bed
Colour
Black
Yellow
Red
Pink
Green
Physiological State
Necrotic
Sloughy
Granulating
Epithelializing
Infected?
Characteristics of granulation tissue
Healthy tissue
Unhealthy tissue
Bright red
Dark red
Moist
Dehydrated
Shiny
Dull
Does not bleed
Bleeds easily
35
Granulating
(WHRU)
Necrosis
(WHRU)
Slough
Clinical appearance
of
surrounding skin
Maceration
Excoriation
Erythema and oedema
Eczema and dry skin
Exudate
• Quantity – Small , moderate copious is
dressing containing exudate?
• Colour – Green? serous?, haemoserrous?
• Consistency – Thick?Thin,
Pain
• When does it occur?
• How bad (intense) is it?
• How does the patient
describe it?
• What makes it better?
• If there are any changes in the wound report
immediately to your nurse in charge
• Any delay in a reassessment may result in
inappropriate treatment