We’re covering ONLY the membranes of the body for now—specific tissue types are covered elsewhere.

For more information:
Introduction to Tissues
Tissues Organs Systems

Membranes

Epithelial membranes

• Epithelial membranes have two layers: epithelial and connective (joined by a gluelike basement membrane)

Serous membranes

• Line cavities that are not open to the external environment
  • Examples
    • peritoneum (lines abdominal cavity/covers abdominal organs)
    • pleura (lines pleural cavity/covers lung)
• Usually two layers, formed when one layer folds back on itself to form double layer
  • Visceral layer: the layer against the internal organs (organs=viscera)
  • Parietal layer: the layer against the inside wall of the cavity
  • There is a potential space between the parietal and visceral layers with a small amount of serous fluid
    • Serous fluid is watery fluid that lubricates and holds layers together (cohesive)
    • A potential space is like my pocket: there’s room for a lot of money but it’s usually empty, with both layers of material touching one another and no significant space is between them

Serous membranes.
Ordinarily they have two layers: visceral & parietal

Mucous membranes

• Line cavities that are open to the external environment
  • Examples
    • Lining of mouth, digestive tract, reproductive tract, urinary tract, respiratory tract
• Single layer
• Mucus (noun) refer to a fluid; mucous (adjective) describes something that has mucus on it or is otherwise associated with mucus
• Mucus is a watery secretion that varies in consistency, depending on its function
  • Sometimes watery, as mucus produced by the nose’s lining in an allergy
  • Sometimes sticky, as mucus that normally lines the nose (snot)
  • Sometimes lubricating, as mucus in digestive tract or vagina
  • Sometimes protective, as mucus that protects the stomach’s lining from acid and enzymes

Cutaneous membrane (another name for “skin”)

• Cover surfaces exposed directly to the external environment
• Produces several fluids: sweat, oil, etc.