Histology 1 - Epithelium Flashcards
What is Epithelium?
Tissue that covers or lines body surfaces, cavities, and tubes
What is a Tight Junction (Zonula occludens)?
Cell junction that forms a virtually impermeable barrier to fluid
What is a Adherens Junction (Zonula Adherens)?
Cell junction whose cytoplasmic face is linked to actin filament
What is a Desmosome (Macula Adherens)?
Spot-like junction whose cytoplasmic face is linked to intermediate filament
What is Clostridium perfringens?
- Gram-positive, spore-forming bacteria
- A major cause of food poisoning and gastrointestinal illnesses
- Clostridum perfringens enterotoxin (CPE) binds to Claudin and disrupts tight junction of epithelium
What is Pemphigus vulgaris?
- An autoimmune disorder that cuases blistering and erosion of skin and mucous membranes
- Autoantibodies against desmosome protein (desmoglein)
What is a Gap Junction?
Special intercellular connection - allows movement of ions and small molecules between cells
(ex. electrical coupling of heart muscle cells)
What are Microvilli?
- Cellular membrane protrusion enclosing actin filaments
- Found in the apical surface of epithelial cells involved in absorption, secretion, and mechanotransduction
What is the Basement Membrane and what are Its Functions (6)?
A thin sheet of extracellular matrix (ECM) that underlies epithelium
- Provides structural support for epithelium
- Bridges between epithelium and underlying connective tissue
- Maintains polarity of epithelium
- Filters substances entering epithelium from below
- Concentrates growth factors
- Acts as scaffold for epithelial repair and regeneration
What is a Hemidesmosome?
Attachment of cells with basal lamina whose cytoplasmic face is linked to intermediate filament
What is Bullous pemphigoid?
Autoimmune skin disease that causes formation of large fluid-containing blisters between the epidermis and dermis
Due to autoantibodies against hemidesmosome proteins
How do you Prepare Histologic Sections of Tissues?
Identify the type of epithelium:
Simple squamous epithelium
Allows for efficient transport of various substances
Identify the type of epithelium:
Simple squamous epithelium
Allows for efficient transport of various substances
Identify the type of epithelium:
Simple Squamous Epithelium (mesothelium - simple epithelium lining viscera and body cavities
Secretes lubricants and facilitates movement of viscera
Identify the type of epithelium:
Simple cuboidal epithelium
Identify the type of epithelium:
Simple cuboidal epithelium
Identify the type of epithelium:
Simple columnar epithelium
Identify the type of epithelium:
Simple columnar epithelium
Identify the type of epithelium:
Stratified epithelium
Identify the type of epithelium:
Stratified epithelium
Identify the type of epithelium:
Transitional stratified epithelium
Identify the type of epithelium:
Pseudostratified epithelium
