Tissue Integ pre-work

Introduction to Skin Structure and Functions

  • The skin is the body's largest organ, weighing approximately 6 pounds.

  • Its significant impact on physical and psychological well-being for both healthy and ill individuals is essential for nurses to understand.

  • Understanding the skin's structure and its functions is crucial for patient care, especially in relation to wound classifications, pressure injuries, burns, and wound healing.

  • Upon completion of this lesson, the learner should be able to:

    • Describe the structure, function, and factors affecting the skin, including wound classification and healing.

Functions of the Skin

  • The skin serves several critical functions, including:

    • Regulation of Heat: Regulates body temperature by dilating and constricting blood vessels and producing perspiration in response to changes in internal and external temperatures.

    • Sensation: Provides tactile feedback for identifying objects in the environment and alerts the body to potential dangers through sensations of pain, pressure, and temperature extremes.

    • Production of Vitamin D: Synthesizes vitamin D when exposed to sunlight.

    • Regulation of Toxins and Fluid Levels:

    • Assists with eliminating toxins and wastes (e.g., ammonia and urea) through sweat.

    • Helps maintain fluid and electrolyte balance.

    • Protection: Protects organs, nerves, tissues, blood vessels, and bodily fluids; acts as a barrier against environmental hazards like ultraviolet light, chemicals, microbes, and pathogens.

    • Maintains skin’s acidic pH to ward off pathogens.

    • Langerhans cells in the epidermis assist the immune system in digesting bacteria and responding to foreign materials.

    • Composition of Self-Image: Influences a person's self-perception, cultural identity, body image, and overall individuality.

Layers of the Skin

  • The skin is comprised of three main layers:

    • Epidermis:

    • The outermost layer of skin.

    • Lacks blood supply (no arteries or veins).

    • Renews itself every 4 to 6 weeks.

    • Outermost layer composed of dead cells and produces melanin.

    • Dermis:

    • The middle layer, thicker than the epidermis.

    • Provides strength and elasticity due to elastin and collagen, which also aids in healing.

    • Contains the vascular system supplying nutrients and oxygen.

    • Subcutaneous Layer (Hypodermis):

    • The bottom layer, consisting of adipose (fat) tissue.

    • Varies in thickness based on weight, sex, and age.

    • Provides cushioning for internal organs and insulation against temperature extremes while connecting the dermis to muscles and bones.

Structures Within the Skin

  • Glands and structures located within the skin layers include:

    • Sudoriferous (Sweat) Glands: Responsible for sweating and temperature regulation.

    • Sebaceous (Oil) Glands: Produce oil to waterproof and lubricate the skin.

Factors Affecting Skin Integrity

  • Skin integrity can be influenced by both positive and negative factors. Damaged skin can break the first line of defense, causing vulnerability to infections, fluid loss, and heat loss.

    • Perfusion:

    • Positive Effects: Adequate perfusion provides oxygen and nutrients essential for maintaining a healthy protective skin barrier.

    • Negative Effects: Poor perfusion decreases oxygen and nutrient supply, leading to skin deterioration and reduced collagen formation. Consequences include:

      • Decreased collagen formation.

      • Reduced production of collagen-producing cells (fibroblasts).

      • Decrease in white blood cell counts (leukocytes).

      • Impaired skin regeneration from reduced cell migration.

    • Moisture/Hydration:

    • Positive Effects: Adequate moisture maintains skin hydration.

    • Negative Effects: Excess moisture can lead to maceration, softening, and erosion of skin, increasing infection risk. Conversely, lack of moisture leads to skin cracking and breakdown.

    • Nutrition:

    • Positive Effects: Sufficient intake of proteins, carbohydrates, fats, vitamins, and minerals supports skin repair and maintenance.

    • Negative Effects: Nutritional deficiencies, particularly in calories, protein, vitamins C & A, and minerals like zinc and copper, weaken skin. Malnutrition coupled with significant weight loss and low BMI affects healing capacity.

    • Medications:

    • Positive Effects: Antibiotics combat infections and enhance healing.

    • Negative Effects: Steroids can impair inflammatory processes, heightening infection risk and slowing healing. Certain medications may cause photosensitivity, leading to skin reactions.

Negative Factors Affecting Skin Integrity

  • Factors leading to adverse effects on the skin include:

    • Friction and Shear:

    • Friction: Damages the top layer of skin through rubbing against surfaces.

    • Shear: Occurs when gravity combines with friction, causing blood vessels to stretch and compress.

    • Prolonged Pressure:

    • Can lead to collapsing capillaries, ischemia, skin damage, and tissue death. Risk increases with long or high pressure on bony prominences.

    • Comorbid Conditions:

    • Diabetes Effects: Alters blood vessel health, reduces skin's ability to fight infections, thickens vessel walls, decreases collagen synthesis, and impairs immune response.

    • Smoking Effects: Reduces oxygen transport, constricts vessels, and contributes to aging skin effects.

    • Ultraviolet Light:

    • Types: UVA and UVB.

    • Causes degenerative changes in skin cells and alters skin DNA, increasing skin cancer risk.

Effects of Aging on Skin Structure

  • Age-Related Changes:

    • Epidermis: Thins and loses Langerhans cells, raising infection susceptibility.

    • Dermis and Hypodermis: Decrease in thickness leads to loss of insulation and cushioning, increasing injury risks.

    • Hair: Loss of melanocytes leads to gray hair and increased skin cancer risk with prolonged UV exposure.

    • Collagen Fibers: Disorganization in number, decreasing skin firmness and repair efficacy.

    • Vascular Tissue: Reduction resulting in diminished blood supply and perfusion.

    • Sweat Glands: Decrease, contributing to skin dryness.

Wound Classification

  • Recognizing various wound classifications is vital for effective communication and treatment:

    • By Integrity of Skin:

    • Open Wounds: Skin broken; susceptible to infection (e.g., cuts, surgical incisions).

    • Closed Wounds: Intact skin, but internal injuries may exist (e.g., bruises).

    • By Cause:

    • Intentional: e.g., surgery.

    • Unintentional: e.g., accidents.

    • By Descriptive Types:

    • e.g., arterial ulcers, pressure injuries.

    • By Depth:

    • Superficial: Only the epidermis affected.

    • Partial Thickness: Extends through the epidermis to the dermis.

    • Deep/Full Thickness: Affects all layers, potentially involving muscle or bone.

    • By Healing Time:

    • Acute: Heals quickly.

    • Chronic: Heals slower than expected.

    • By Contamination Level:

    • Clean: No infection present.

    • Dirty: Infected wound.

Classification of Burns

  • Superficial Burns:

    • Affect the epidermis; cause pain, redness without edema.

  • Partial Thickness Burns:

    • Affect epidermis and part or all of dermis, resulting in blisters and extreme pain.

  • Full Thickness Burns:

    • Affect all skin layers; tissue may appear dry or charred, causing no pain due to destroyed nerve endings.

Stages of Pressure Injuries

  • Stage 1 Injuries: Intact skin with non-blanchable erythema; painful, differing in temperature.

  • Stage 2 Injuries: Partial-thickness wound involving epidermis and dermis; shallow and pink with possible intact blisters.

  • Stage 3 Injuries: Full-thickness extending to subcutaneous tissue; may show tunneling or undermining.

  • Stage 4 Injuries: Deeper injury involving exposed muscle or bone; infected if bone is exposed.

  • Unstageable Injuries: Full-thickness with necrotic tissue where depth cannot be assessed until tissue is removed.

Types of Healing

  • Primary Intention: Swift healing with minimal scarring; seen in surgical incisions or approximated wounds.

  • Secondary Intention: Healing from the bottom and sides of a wound, common in chronic wounds; slower.

  • Tertiary Intention: Open wound initially left to drain before closure to allow for treatment of infection risk.

Phases of Wound Healing

  • Inflammatory Phase: Starts with hemostasis; blood vessels dilate, forming clots and releasing growth factors; lasts about 3 days.

  • Proliferative Phase: Wound fills with granulation tissue, where fibroblasts play a key role; epithelial cells migrate to optimize healing.

  • Maturation/Remodeling Phase: Collagen remodeling occurs, scar tissue forms but reaches only 80% original strength; can last up to a year.

Complications Affecting Wound Healing

  • Hemorrhage: Leads to internal or external bleeding; may cause medical emergencies if untreated.

  • Infection: Can slow healing and complicate recovery.

  • Dehiscence: Partial or complete tissue layer separation post-surgery.

  • Evisceration: Protrusion of internal organs through an opened wound; requires immediate medical attention.

  • Fistula: Abnormal connections form between organs or skin.

Causes of Complications

  • Increased physical stress on healing tissues, obesity, or certain diseases can exacerbate conditions.

  • Poor healing indicators include lack of a healing ridge, excessive bleeding, and signs of infection.