The Integumentary System and Wound Healing. Learning outcomes Describe the anatomy and functions of...
-
Upload
lynn-mclaughlin -
Category
Documents
-
view
225 -
download
1
Transcript of The Integumentary System and Wound Healing. Learning outcomes Describe the anatomy and functions of...
Learning outcomes
• Describe the anatomy and functions of the skin
• Discuss the principles of wound healing
Quick RevisionLabel the diagram
U of M: General College: web anatomy.http://www.msjensen.gen.umn.edu/webanatomy/wa_cell_chem/wa_wcb_skin1.htm
1- stratum corneum2 – Merocine sweat gland3- Arrector pilli muscle4 – Arteriole5 – Venule6 – Motor nerve7 - Sensory nerve8 – Hypodermis9 – Dermis10 - epidermis
Some facts
• Skin - the largest organ of the body• 12-15% of body weight• With a surface area of 1-2 meters • Skin is continuous with, but structurally
distinct from mucous membranes that line the mouth, anus, urethra and vagina.
• Forms a barrier to the environment• INTEGUMENT comes from a LATIN word
that means to COVER.
Consists of………
• The epidermis – contains keratin to protect the body from damage
• The dermis – maintains shape
• Integral structures – hair, glands, nails and nerve endings
Epidermis
• Superficial layer- stratified squamous epithelium
• Varies in thickness – wear and tear• 4 types of cells
– Keratinocytes – toughen and waterproof the skin– Melanocytes –melanin, transports the
keratinocytes = colour, protects the nucleus (DNA) from ultraviolet light
– Langerhans – produced in the bone marrow and migrate to the skin where they aid the immune system
– Merked cells – involved in the sensation of touch
• Consists of 4 principle layers
• Its layers are made of Mostly DEAD CELLS.
• Undergoing successive stages of development
• Keratinocytes mature as they push to the surface – accumulate keratin and loose their cytoplasm and nucleus and die
• Then shed – every 3-4 weeks
Dermis• Connective tissue (collagen and elastic
fibres)• Role in homeostasis
On a cold day when the body needs to conserve heat, the Blood Vessels in the Dermis NARROW.
On hot days, the Blood Vessels WIDEN, warming the skin and increasing heat loss.
• Role in wound healing• Hair follicles, nerves, glands and blood
vessels embedded in the dermis• Papillae in the dermis create ridges
Subcutaneous layer
• Layer of adipose tissue
• Plexus of blood vessels
• Provides protection between bony prominences and the skin surface
• Maintains the warmth of the lower structures
Hairs
• Dead keratinised cells bonded closely together
• Attached to each hair follicle is a bundle of smooth muscle – pulls hair up to trap warm air
• Provide protection– Sebaceous glands keeps the hair soft and
pliable– Prevents evaporation of water– Inhibits bacterial growth
Glands
• Mammary glands
• Sebacoeus glands
• Sweat glands
– Eccrine glands – perspiration – assists temperature control and removes waste products
– Apocrine glands – axilla, areola and pubic area
Nails
1. Nails are protective coverings over the ends of fingers and toes.
2. Nails consist of stratified squamous epithelial cells overlying the nail bed, with the lunula as the most actively growing region of the nail root
3. As new cells are produced, older ones are pushed outward and become keratinized
Department of Podiatry - Nail Structure and Functionhttp://www.latrobe.edu.au/podiatry/nails.htm
Functions of the skin
• Support - The skin acts as a flexible physical support and covering for underlying tissues.
• Temperature - Through its extensive blood supply and sweat glands, the mammalian skin is able to maintain the constant temperature of a homoiotherm.
• Excretion - Waste materials such as salts and water are removed from the body via the skin's sweat glands.
• Vitamin formation - Photochemical action in skin produces vitamin D. The skin is our primary source.
• Sensory function - Through the extensive network of sensory receptors we have sensations of pressure, texture, temperature and pain.
• Pigmentation - Melanin pigments protect against the excesses of ultra violet light.
• Protection - The epidermis prevents desiccation of the internal organs and so provides the fundamental requirement for mammalian land colonization - freedom from water dependence. It prevents absorption of unwanted and potentially dangerous chemicals.
• Immunological defense - The epidermis particularly the stratum corneum (the outer most keratinized skin layer), provides a passive defense against entry of opportunistic pathogenic organisms.
• Skin also performs an active role in immunity through immunological surveillance.
Integumentaryhttp://www.kumc.edu/instruction/medicine/anatomy/histoweb/skin/skin.htm
Changes in pregnancy
• The surface area increases
• The skin is more elastic
• Increased skin pigmentation
• Striae gravidarum
• Pruitis gravidarum
• Increased greasiness of the skin
• Nerve endings within the integumentary system will add to the experience of labour
(personal contact,massage, warmth)
• Most of the changes return to normal in the postnatal period
What as midwives may we notice about the skin?
• Scars
• Bruises
• Skin conditions
• Puncture sites
• Warts
• Herpes
The neonate
• At term the epidermis is well developed and keratinised
• Sweat glands are present but initially not very active
• High surface area• Thin• Premature babies – thinner skin• Post term babies – dry skin – peeling• Rapidly colonised with commensals• Milia
Protection
• Vernix caseosa– Develops from 5th month of
pregnancy– Prevents electrolyte loss– Absorbed into the fetus near term
• Lanugo– Fine covering of hair from 20th week
of pregnancy – shed by 36 weeks
Thermoregulation
• Vital• Unable to conserve heat as
efficiently as an adult– Evaporation – Convection– Radiation– Conduction
Non- shivering thermogenisis
• Adequate stores of or access to glucose and oxygen will maintain temperature
• Specialised layer of adipose tissue called brown fat from 28th week gestation
• Metabolism of brown fat = heat = lipolysis = breakdown of fat– Limited amount available, so then the
available glucose used = metabolic acidosis
Classifying wounds
A wound can bedefined as:“A cut or break inthe continuity ofany tissue, causedby injury oroperation” (Baillière’s 23rd Ed)
Wounds can be classifiedaccording to their nature:• Abrasion• Contusion• Incision• Laceration• Open• Penetrating• Puncture• Septic etc……………
http://www.nursingtimescareers.co.uk/NTCareersLondon2005/presentations/WC 22.06 SR2 11&1.ppthttp://www.nursingtimescareers.co.uk/NTCareersLondon2005/presentations/WC%2022.06%20SR2%2011&1.ppt
Classifying wounds
Wounds may be classified according to thenumber of skin layers involved:
Superficial Involves only the epidermis
Partial Thickness Involves the epidermis and the dermis
Full Thickness Involves the epidermis, dermis, fat, fascia and
exposes bone
Physiology of wound healing
There are 4 phases of wound healing
1. Haemostasis
2. Inflammation
3. Proliferation
4. Maturation
• The length of time taken to progress through these phases varies for each wound
Haemostasis
• Begins immediately there is tissue damage• Vasoconstriction occurs to minimise bleeding
and assist with initiating the clotting process• A fibrin clot forms, temporarily closing the
wound• Whilst the clot forms, blood or serous fluid
may exude from the wound as the body tries to cleanse the wound naturally
Inflammation
• Heat, redness, pain, swelling and some loss of function occurs as the vessels around the wound dilate.
• Macrophages clear the wound of debris to prepare for new tissue growth
• A small necrotic area forms around the wound margin• Epithelial cells from the wound margin move under
the base of the clot, the surrounding epithelium thickens and a thin layer of epithelial tissue forms over the wound.
• This phase lasts around 36hrs, but is prolonged in the presence of infection
Proliferation – involves 3 stages
Granulation• Capillaries from the surrounding tissues grow
into the wound bed• At the same time fibroblasts produce collagen
fibres, providing the framework for new connective tissue formation
• Healthy granulation tissue has a bright red, moist, shiny appearance, a ‘pebbled’ looking base & does not bleed easily
Proliferation
Wound contraction• Once the wound is filled with connective
tissue, fibroblasts collect around the edge of the wound and contract, pulling the edges together
• A firmer, fibrous epithelial scar forms, as the fibroblasts and collagen fibres begin to shrink, resulting in contraction of the area
• This occurs only in healthy tissue that has not been sutured
Proliferation
Epithelialisation• New epithelial cells grow over the wound
surface to form a new outer layer
• Wound appears whitish-pink and translucent
Maturation
• Re-modelling occurs to increase the tensile strength of the scar tissue
• The scar initially appears red & raised, and then with time changes to a paler, smoother, flatter appearance
• Mature scar tissue is avascular and contains no sweat or sebaceous glands or hairs
• This phase can take up to 2 years to complete
Types of healing
Primary intention• Surgical wounds• Sutured minor injuries
Secondary intention• Pressure sores• Ulcers
Factors that influence wound healing
Nutritional status• An adequate intake of protein, vitamin A & C,
copper, and zinc is required. • Proteins supply amino acids essential for
tissue repair and regeneration• Vitamin A & zinc are required for
epithelialisation• Vitamin C & zinc are required for collagen
synthesis and capillary integrity
Factors that influence wound healing
• Smoking – interferes with the uptake and release of oxygen to the tissues, resulting in poor tissue perfusion
• Increasing age – affects all phases of wound healing due to impaired circulation and coagulation, slower inflammatory response and decreased fibroblast activity
• Obesity – fatty tissue can have an inadequate blood supply resulting in slower healing and decrease resistance to infection
Factors that influence wound healing
• Wound stress – e.g. prolonged or violent vomiting, abdominal distension, may cause sudden tension on the wound, inhibiting the formation of collagen networks and connective tissue
• Infection – causes increased inflammation and necrosis which delays wound healing
• Other factors include anti-inflammatory drugs or underlying disease such as diabetes mellitus
Wound assessment
WOUND ASSESSMENT
Lab tests: ABI/ TcPO2 Size, depth
& location
Wound bed:
• necrosis
• granulationSurrounding skin: colour, moisture, suppleness
Wound edge
Odour or exudate
Signs of infection
Fantasy Or Reality?
• Happy• Fulfilled• Ecstatic• Euphoric• Blooming
• Smelly• Exhausted• Stitches• Sore• Aching• Infected• Unlovable
Clinical appearance
Describes the type of material present
In the base of the wound:
Slough (yellow)
Necrotic tissue (black)
Infected tissue (green)
Granulating tissue (red)
Epithelialising (pink)
Morbidity after Caesarean Section
• 9.5% of women reported NO problems• 49% of women reported three or more problems• 58% had pyrexia• 21% had wound leakage• 11% had UTI• 7% had wound infection• 4% had uterine infections
A quarter of these women had not spoken to any health care professional
(Hillan 1995)
Tissue ViabilityDocumenting wound care
Potential for litigation
Good staff communication
Continuity of care
To assess progress or deterioration
Should be factual not subjective
Wound assessment charts
References BROWN, S. AND LUMLEY, J., 1998. British journal of obstetrics
and gynaecology, 105, 156-161. CHAMBERS, N., 1999. Wound management. In: R. HOGSTON,
AND P.M. SIMPSON, eds. Foundations of nursing practice. Basingstoke: Macmillan Press Ltd, 240-266.
HILLAN, E., 1995. Journal of advanced nursing, 22(6), 1035-1042.
JOHNSON, R. AND TAYLOR, W., 2000. Skills for midwifery practice. London: Churchill Livingstone
MANGAN, P., 2002. Nursing & Residential Care. 4 (6), 270-274 MCCLOSKEY, R. V., KUMAR, P. D., SCHECHTER, F. G.,
CARTER, R. L., NIEUWENHUIS, H. K., CHRISTIAENS, G.C.M. L. 1997. Heparin-Induced Skin Necrosis. New England Journal of Medicine, 336 (10), 588-589.
• MORRISON, B. AND BAKER, C., 2001. How to raise awareness of pressure sore prevention. British Journal of Midwifery. 9 (3), 147-150.
• WYLIE, L., 2000. Essential Anatomy and Physiology in Maternity Care. Churchill Livingstone.