Integumentary System - BSC 103 (Anaphy Lec)

• Body Membranes


  Structures that cover body surfaces, line body cavities, and form protective sheets around organs
• Functions of body membranes


  • Cover body surfaces
  • Line body cavities
  • Form protective sheets around organs
• Classification of body membranes


  • Epithelial membranes
  • Connective tissue membranes
• Epithelial membranes


  • Cutaneous membranes (skin)
  • Mucous membranes
  • Serous membranes
• Connective tissue membranes


  Synovial membranes
• Epithelial membranes


  • Contain epithelial tissue layer
  • Contain connective tissue layer
• Major epithelial membranes


  • Cutaneous membrane
  • Mucous membrane
  • Serous membrane
• Cutaneous membrane


  • Dry membrane
  • Outermost protective boundary
• Construction of cutaneous membrane

  1. Epidermis is composed of keratinized stratified squamous epithelium

  2. Dermis is mostly dense (fibrous) connective tissue
• Cutaneous membrane covers the body
• Mucous membranes


  Moist membranes
• Mucous membranes


  • Line all body cavities that open to the exterior body surface
  • Adapted for absorption or secretion
• Construction of mucous membrane

  1. Epithelium type depends on site

  2. Loose connective tissue (lamina propria)
• Mucous membranes line body cavities open to the exterior
• Serous membranes


  Line open body cavities that are closed to the exterior of the body
• Serous membranes


  • Occur in pairs, separated by serous fluid, with a visceral and parietal layer
• Construction of serous membranes

  1. Simple squamous epithelium

  2. Areolar connective tissue
• Serous membranes line body cavities closed to the exterior
• Relationship between parietal and visceral serous membrane layers

  • Outer balloon wall (comparable to parietal serosa)
  • Air (comparable to serous cavity)
  • Inner balloon wall (comparable to visceral serosa)
• Major Epithelial Membranes


  • Peritoneum
  • Pleura
  • Pericardium
• Peritoneum


  Abdominal cavity
• Pleura


  Around the lungs
• Pericardium


  Around the heart
• Major Connective Tissue Membranes

  • Synovial membranes
  • Loose areolar connective tissue
  • Fibrous capsules surrounding joints
  • Bursae
  • Tendon sheaths
• Synovial membranes, bursae, tendon sheaths

  • Secrete a lubricating fluid to cushion organs moving against each other during muscle activity
• Components of the Integumentary System

  • Skin (cutaneous membrane)
  • Sweat glands
  • Oil glands
  • Hair
  • Nails
• Functions of the Integumentary System

  • Insulates and cushions
  • Protects from mechanical, chemical, thermal, UV, and microbial damage
  • Aids in loss or retention of body heat
  • Aids in excretion of urea and uric acid
  • Synthesizes vitamin D
• Hypodermis (subcutaneous layer)


  Not technically part of the integumentary system but among its functions, it anchors the skin to the underlying tissues and organs, composed mostly of adipose tissue and connective tissue, contains lamellated (pacian) corpuscles which detect external pressure applied to the skin, serves as a shock absorber and insulates deeper tissues
• Hypodermis (subcutaneous layer)


  One of the two kinds of tissue that compose the skin
• Skin


  • Serves as a shock absorber
  • Insulates deeper tissues
• Epidermis


  • Capable of being hard and tough
  • Avascular
• Keratinocytes


  • The most common cell in the epidermis
  • Produce a fibrous protein called keratin
• Keratin


  • Finds in the outermost layer of skin
  • Helps waterproof the skin
  • Protects the skin and underlying tissues from heat, microbes, abrasion and chemosis
  • Helps make hair and nails hard and rigid
• Keratinization


  • A process by which keratin hardens
  • Cells that produce keratin are stronger than other cells
  • Makes them good at forming a barrier between the outside world and the inside of the body
• Keratinization


  1. Begins in the stratum spinosum

  2. Actual keratinocytes begin in the stratum basale
• Layers of the epidermis (from deepest to most superficial)

  • Stratum basale
  • Stratum spinosum
  • Stratum granulosum
  • Stratum lucidum
  • Stratum corneum
• Stratum corneum


  • The outermost, most superficial layer of the epidermis
  • Consists of 20-30 layers of dead, flat keratinocytes filled with keratin
• Stratum lucidum


  • Only present in thick, hairless skin of palms and soles
  • Consists of 2-3 layers of clear, flat dead keratinocytes
• Stratum granulosum


  • The first layer to contain living cells
  • Has a grainy appearance due to cells producing keratin
• Stratum spinosum


  Cells look spiny due to tiny filaments joining them together