Tissues: Epithelium Flashcards
Tissue
group of specialized cells
Four primary Tissues
Epithelium, Connective, Muscle, Nerve
Ematopoisis
formation of blood cells
Epethilium
sheet of tissues that covers a body surface or lines body cavity
- basal surface attached to basement membrane
- always connected to connective tissue
- avascular and inervative
- rapid regeneration (GOOD- are prone to lots of friction)
Two types of epithelium
covering/lining
glandular (protection, lubrication, chemical signaling)
Apical Surface
surface that is either on the outside or inside a lumen
Basement membrane
seperates the epethilium from the connective tissue
Functions of Epithelial Tissue
protection barrier permeability sensation absorption
Classification : Cell Layers
simple = one cell layer stratified = more than one layer pesuedostratified = really simple columnar
Classification : Cell Shape
Squamous = flat Cuboidal = square Columnar = tall
Squamous Epithelium
Simple Squamous
thin and flat
- 1 layer thick (delicate)
- found in linings of blood vessels and lungs (absorption)
Stratified squamous
- forms many layers thick (against physical and chem attacks)
- found on outside of body (epidermis, dermis)
Keratinized stratified squamous epithelium
apical layers of skin cells (tough and water resistant)
- packed with fibrous protein keratin
Nonkeratinized stratified squamous epithelium
resists abrasions but dries out (must be well lubricated)
- found in vaginal and oral cavities
Cuboidal Epithelium
Simple cubodial
occurs where secretion or absorption takes place (lining of kidney tubules)
Stratified cubodial
RARE, but found in ducts of sweat and mammary glands
Transitional Epithelium
tolerate repeated cycles of stretching without damage (urinary bladder)
- called transitional because cell layers change appearance (from stratified to more as they stretch)