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. Epidermis is outer layer and varies in thickness 0.1mm-on eyelids and 1mm thick on Palms and soles Acidic= PH 5.5 Has five layers corneum,lucidium,granulosum,spinosum, basale Dermis – deeper layer composed of collogen fibres and elastin fibres( skins elasticity and stregnth)

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?

Acid PH helps to prevent infection Protection of internal structures – physical barrier to microorganisms and foreign matter. Acid PH helps to prevent infection Damage to skin impairs ability to carry out these functions. Ordinary washing = 45 mins. to restore skin Ph Prolonged exposure = up to 19 hours

Sensory perception- Allows you to feel pain, pressure heat this helps us to identify potential dangers and avoid injury

Thermoregulation- Blood 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

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

Chronic wounds Characterised by: Underlying pathology e.g. venous insufficiency Prolonged duration Hyperactive state Persistent state of inflammation

Wounds go through 4 distinct phases

Normal Wound Healing Response Proteoglycans Fibroblasts Collagen Angiogenesis Collagen remodelling Scar maturation Neutrophils Macrophages Lymphocytes MATURATION PROLIFERATION Platelets Fibrin 0 – 3 days: The first phase of wound healing occurs immediately at the time of injury. During this phase, there is increased blood supply to the area, platelets aggregate to form a temporary plug & fibrin which forms a mesh as the body attempts to clot off any bleeding vessels allowing haemostasis to occur. This blood clot or scab is part of a natural covering mechanism creating a new barrier for the broken skin to protect the underlying tissues from harmful bacterial invasion. 1 – 6 days: Following this the natural inflammatory response occurs. It consists of widespread vasodilation, oedema formation and the migration of cells such as neutrophils (whose function is the phagocytosis of bacteria), macrophages (which also destroy bacteria but are also a rich source of biological regulators that are essential for the normal wound healing process) & lymphocytes (white blood cells involved in the immune response). 3 – 24 days: During the proliferation phase the extracellular matrix (the supporting structure of new tissue) is formed and remodelled, with angiogenesis (new blood vessel development), epithelisation (new skin cells) & wound contraction taking place. During this phase fibroblasts play an important role in the manufacture of collagen (protein responsible for holding the body together, skeleton included), along with other substances such as proteogylcans to form the ECM, which fills the wound space and provides a scaffold for the new tissue. 24 – 365 days: The maturation phase can last for many months after skin cover has been achieved. The initially formed ECM is remodelled, while collagen increases the tensile strength of the wound. NB Stages overlap INFLAMMATION HAEMOSTASIS MINUTES DAYS WEEKS MONTHS / YEARS (whru)

Haemostasis Starts immediately after injury. Blood vessel contraction (vasoconstriction) Vasoconstriction minimises blood loss

Inflammatory phase Occurs between 0-3 days Vascular permeability increases and serrous fluid ( comprising of cell and plasma protein) accumulates in surrounding tissue causing swellling redness and warmth

Proliferation 0-24 days During this phase growth factors prompt fibroblasts to migrate to the wound. They make new fibres and ground substnaces (ECM) provides support to cells Fibroblasts start at wound edge then spread over surface. – require o2 to perform this task

Maturation 20 days – 2 years Closure of wound and re-epithelisation. Scar maturation

What factors may affect wound healing? ASK AUDIENCE

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 Age – in old age the inflammatory response, proliferation phase and maturation are diminished. Anaemia – lack of red blood cells Anti-inflammatory – suppress the normal inflammatory response to injury. Cytotoxic drugs – interfere with cell proliferation and severely impair healing. Also neutropenia makes the patient more susceptible to infection. Nausea / vomiting leads to poor nutritional intake and dehydration. Diabetes – many factors are thought to impair wound healing, though no single factor alone is responsible. Hormones - Jaundice - excess of bilirubin (bile) from the liver Nutritional status – despite malnutrition healing has been demonstrated to take place, improved nutrition would reduce the complications and length of hospital stay. There are discrepancies in the literature relating to obesity and wound healing. Problems such as performing surgery are very high. Temperature - Any substance used should be at body temperature as it takes 40 mins for the wound to return to normal body temp after cleansing and Mitotic cell division can be delayed for up to 3 hours Uraemia – excess of urea (waste products from the kidneys in the urine) Vitamins – Vit A deficiency inhibits the keratinisation process; Vit C deficiency causes wound dehiscence, reduces tensile strength and adversely affects angiogenesis. Zinc is essential in fibroblast epithelialisation, cofactor for protein synthesis & for metalloproteinase production in the ECM. Stress & anxiety can affect the immune system, can disturb sleep, which is important for healing and tissue repair. Altered body image due to disfiguring wounds or surgery can adversely affect patients’ psychological state.

Factors affecting healing Local Factors Blood supply Denervation Haematoma Local Infection Duration Wound bed condition Anatomical site Size of wound Classic infection – clearly infected, red, hot, smelly and bleeding. 5th toe already amputated. 4th toe sausage shaped. Neuropathy Eventually had a below knee amputation. Denervation – interruption of the nerve supply to the muscles and skin.

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 Physiological State Black Necrotic Yellow Sloughy Red Granulating Pink Epithelializing Green Infected?

Characteristics of granulation tissue Healthy tissue Bright red Moist Shiny Does not bleed Unhealthy tissue Dark red Dehydrated Dull Bleeds easily S

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