Integumentary System

Integumentary System

• Largest organ of the body

• Components of Integumentary System

  • Includes skin, hair, and nails

  • Skin has been called a membrane and an organ

  • Average adult skin covers over 3000 square inches

Layers of the Skin

• Epidermis

  • Outermost layer

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

  • Basal Layer

    • Deepest layer filled with keratin

    • Constant growth and multiplication pushes cells upward to the outer layer

  • Stratum Corneum

    • Upper layer comprised of dead cells filled with karatin

      • Karatin: a hard protein material

  • Functions of Basal Layer

    • Contains melanocytes filled with a pigment called melanin

    • Melanin is a black or brown pigment produced by melanocytes that determines skin color and protects against sunlight

• 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 Layer (Hypodermis)

  • Beneath dermis

  • Consists of adipose tissue and fat

    • Adipose tissue: adipocytes produce fat. Adipose tissue protects deeper tissues of the body. Acts as a heat insulator and energy source

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

  • Curly hair is usually dry

• Nails

  • Nonliving

  • Composed mainly of keratin

  • Develop from a growing region at the proximal end

  • Functions as protection

• Dermal papillae

  • Fingerprints

  • Forms ridges and mounds on the fingers and toes

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 is an energy source

• Absorption

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

• Excretion

  • Perspiration eliminates salt, waste, water, heat

• Production

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

Roots, Suffixes, Prefixes

• adip/o - fat

• cutane/o - skin

• derm/o - skin

• hidr/o - sweat

• kerat/o - hard

• lip/o - fat

• erythr/o - red

• melan/o - black

• xanth/o - yellow

• onycho/o - nails

• squam/o - scales

• trich/o - hair

Diseases

• Impetigo: bacterial skin infection characterized by isolated pustules that become crusted and rupture; contagious

• Onychomycosis: fungal infection of the nail

• Systemic Lupus Erthematosus: Chronic autoimmune inflammatory disease

• Acne Vulgaris: inflammation of the sebaceous gland

• Ringworm: fungal infection of the skin

• Melanoma: black tumor, skin cancer

• Epidermolysis bullosa: genetic disease causing loosening and blistering of the skin

• Second degree burn: skin deep red and blistering

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

• Dermatologist: specializes in treating skin diseases and disorders