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Integumentary System

• Overview: The integumentary system includes the skin and its accessory structures, playing a crucial role in protecting the body.

Basic Anatomy of the Skin

• Layers of the Skin: The skin comprises two primary layers:

  • Epidermis: The outermost layer that contains multiple sub-layers.

  • Dermis: The deeper layer that supports and nourishes the epidermis.

Layers of the Epidermis

• Stratum Basale (Basal Layer): Contains stem cells that produce new skin cells.

  • Stem Cells: The source of new skin cell production, typically live 40-50 days before they are shed.

  • Daughter Cells: These are pushed outward from the basal layer to form the upper layers of the epidermis.

• Comparison of Skin Types:

  • Thick Skin: Found on the palms of hands and soles of feet; has more layers for added protection.

  • Thin Skin: Found in most other areas; has fewer layers of epidermis.

Structure of the Dermis

• Dermal Composition: The dermis is made up of connective tissue, blood vessels, and nerve endings.

• Epidermal Ridges: These structures form fingerprints and enhance grip on surfaces.

• Tension Lines: Gaps between collagen fibers in the reticular layer of the dermis, indicating the direction of skin tension.

Skin Tone and Melanin

• Melanin Production: Influenced by UV radiation levels; higher exposure can increase melanin production.

• Vitamin Levels:

  • Vitamin B9 (Folate): Levels decrease with increased UV exposure.

  • Vitamin D: Levels increase with melanin production as a response to UV radiation.

Accessory Structures

• Hair: Serves various functions including protection and thermal regulation.

• Nails: Protective coverings of the dorsal aspect of the fingers and toes.

• Glands: Include sweat glands (thermoregulation) and sebaceous glands (oil production).

Skin Burns Classification

• Types of Burns:

  1. 1st Degree: Affects the outer layer, causing redness and minor pain.

  2. 2nd Degree: Affects both the epidermis and part of the dermis, resulting in blisters and more intense pain.

  3. 3rd Degree: Extends through the entire dermis, possibly affecting deeper tissues; may appear white, charred, or leathery.

Skin Cancer Types

• Basal Cell Carcinoma: Cancer of keratinocytes in the stratum basale; usually presents as a nodule with a cratered center.

• Squamous Cell Carcinoma: Arises from keratinocytes in the stratum spinosum; may form plaques that bleed or ulcerate.

• Malignant Melanoma: Cancer of melanocytes; characterized by asymmetrical shape, irregular borders, blue-black color, larger diameter, and evolving nature.