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.