The Integumentary System and Wound Healing

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

Integral structures

• Hairs

• Glands

• Nails

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

So what are the functions of the skin?

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

Sweat Gland

Hair Follicle

Hair Bulb

Sebaceous Gland

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

              

      

www.skin-science.com/ _int/_en/topic/topic_sou...

www.stretchmarkcure.com/ photos.htm

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

How can midwives prevent hypothermia or hyperthermia

Wound - a definition

‘Any kind of breach in the integrity of the skin or underlying tissues’

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

www-ermm.cbcu.cam.ac.uk/ 03005829h.htm

Schematic Diagram of the Phases of Wound Healing

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)

Wounds and midwifery – what do you think?

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)

Is this wound midwifery related?

(McCloskey et al. 1997)

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.