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Overview of the Integumentary System

Apr 9, 2025

Integumentary System Overview

Components of the Integumentary System

  • Skin
  • Hair
  • Nails
  • Sweat Glands
  • Sebaceous (Oil) Glands

Skin Structure

Major Layers of the Skin

  1. Epidermis

    • Superficial layer
    • Composed of epithelial tissue
    • Avascular (lacks blood vessels)
    • Visible layer of skin
    • Made of keratinized stratified squamous epithelium
  2. Dermis

    • Deep to the epidermis
    • Composed of connective tissue
    • Vascular (contains blood vessels)
    • Provides nourishment to the epidermis

Dermis Sub-Layers

  • Papillary Layer

    • Superficial 20% of the dermis
    • Made of loose areolar connective tissue
    • Supports and nourishes the epidermis
  • Reticular Layer

    • Deeper 80% of the dermis
    • Composed of dense irregular connective tissue
    • Provides strength and protection

Hypodermis (Subcutaneous Tissue)

  • Not technically part of the skin, but related
  • Composed mostly of adipose tissue and some areolar connective tissue
  • Functions:
    • Absorbs shock
    • Insulates the body
    • Stores fat
    • Anchors skin to underlying structures (muscle and bone)

Embedded Structures in the Dermis

  • Hair and Ereector Pili Muscle

    • Involved in forming goosebumps
  • Nerves

    • Yellow in diagrams
    • Involved in cutaneous sensations
  • Blood Vessels

    • Store about 20% of the body’s blood
    • Include arteries (red) and veins (blue)
  • Sweat Glands

    • Aid in thermoregulation
  • Sebaceous Glands

    • Associated with hair
    • Secrete oil to condition the skin

Summary

  • The skin is made of two primary layers: the epidermis (epithelial layer) and the dermis (connective tissue layer).
  • The hypodermis, though not part of the skin, plays a supportive role.
  • Understanding the skin's structure and embedded elements helps in comprehending its protective, sensory, and regulatory functions.