Anatomy of the Skin

• Components of Integumentary System

  • Includes skin, hair, and nails

  • Skin serves as a membrane and organ

  • Average adult skin covers over 3000 square inches

Layers of the Skin

• Epidermis

  • Outermost layer

  • Composed of flat, scale-like cells (squamous epithelium)

  • Basal Layer

    • Deepest layer filled with keratin

    • Constant growth pushes cells upward to the outer layer

  • Stratum Corneum

    • Upper layer comprised of dead cells filled with karatin

    • A hard protein material

• Functions of Basal Layer

  • Contains melanocytes filled with a pigment called melanin

  • Melanin determines skin color and protects against sunlight

• Stratum Corneum

  • Outermost epidermis level

  • Protective, flat, dead cells that are continuously shed and replaced

  • Some cells produce melanin

Deeper Skin Layers

• Dermis

  • Below the epidermis (true skin)

  • Composed of connective tissue, nerves, blood vessels, lymphatics, sweat, and oil glands

  • Provides support and nourishment to the skin

• Subcutaneous Tissue

  • Beneath dermis (hypodermis)

  • Consists of connective tissue and fat

Associated Skin Structures

• Glands

  • Sudoriferous Glands (Sweat Glands)

    • Regulate body temperature by releasing sweat

    • Evaporation of sweat cools the body

  • Sebaceous Glands

    • Release sebum (oily fluid)

    • Lubricate hair and skin to prevent dryness

• Hair

  • Nonliving

  • Composed of keratin

  • Develops from follicles

  • Grows from the base in deeper layers of skin

  • Functions as protection

• Nails

  • Nonliving

  • Composed mainly of keratin

  • Develop from a growing region at the proximal end

  • Functions as protection

Functions of the Integumentary System

• Protection

  • Shields against ultraviolet rays and pathogens

• Sensory Perception

  • Nerves help detect pain, temperature, pressure, and touch

• Body Temperature Regulation

  • Blood vessels in skin help retain or lose heat

  • Blood vessels dilate to allow heat loss when hot, blood vessels constricts to retain heat when cold

  • Sudoriferous glands assist in cooling through perspiration evaporation

• Storage

  • Stores fat, glucose, water, vitamins, and salts temporarily

  • Adipose tissue acts as energy source

  • Certain substances can be absorbed through the skin, such as medications

• Absorption

  • Certain substances can be absorbed, like medications

• Excretion

  • Perspiration eliminates salt, waste, water, heat

• Production

  • Initiates vitamin D production using UV rays; matures in the liver

Clinical Aspects of the Skin

• Dermatology

  • Study of skin and related diseases

  • Examination of skin, hair, nails is part of physical examination

  • Evaluation of skin performed through visual observation for color, lesions, pigmentation

  • Palpation used to assess texture, temperature, moisture, firmness, tenderness