Verified | Latest Questions 2025
Intra-epithelial separation - When the cells within the epithelium separate forming a
vesicle filled with fluid from CT
simple epithelium - one layer of cells- all cells touch basement membrane (BM)
stratified epithelium - two or more layers of cells-only basal/bottom layer touches BM
all cells contact BM, but not all cells reach lumen - pseudostratified epithelium
squamous cell shape - flattened nuclei
columnar look - tall and slender
domed - cuboidal shape with a rounded top
simple squamous epithelium function - secretion-provides lubrication.
Functions of simple squamous - rapid exchange/filtration of gases, nutrients, fluids,
waste
location of simple squamous - alveoli of lung, lumen of vessels and heart, glomerulus
(kidney blood vessel)
location of simple squamous - visceral and parietal serosa-serous membranes covers
external surface of visceral organs and line lumen of enclosed body cavities.
What are the major categories of epithelium - Surface epithelium and glandular
epithelium
Surface epithelium - AKA lining epithelium
Cover external body surface and outside organ surfaces, lines body cavities, lines
lumen of hollow cavities
Glandular epithelium - forms exocrine and endocrine glands through invagination and
folding of the epithlial cells into compact structures.
Endocrine - Secrete product into blood
Exocrine - Secrete product into ducts
Common structural characteristics of all epithelium - Polarized cells (apex and base)
Intercellular adhesions
, Anchored to a basement membrane (ECM)
Avascular (no blood vessels)
Rapid renewing
One or multiple cell functions
Key functions of epithelial cells - Barrier/protection
Conduit
Transport/exchange (paracellular and transcellular)
Paracellular - Between cells
Transcellular - through the cell
Types of epithelial transport - Absorption and secretion
Apical surface - faces the free surface
Structure related to function
lateral surface - site of cell adhesions between cells
Lateral surface - Region between adjacent cells
Cell adhesions regulate cell cycle and passage of molecules
Controls communication
Provides a barrier and stability
Basal surface - Selectively transport nutrients b/w CT tissue, cell, and lumen
Provides adhesion/stability
What controls top and bottom of an epithelial cell? - cellular adhesions
General functions of surface specialization for epithelial cells - Increase surface area,
provide motility, serve as protective adaptation
If an epithelial cell wants to increase surface area, what specialization might it have? -
microvilli (small intestine and kidney)
Stereocilia (male reproductive tract, inner ear epithelial cells)
If an epithelial cell wants to provide motility, what specialization might it have? - Cilia
(oviduct, conducting portion of respiratory system)
Flagella (sperm)
If an epithelial cell wants to provide protection, what specialization might it have? -
keratin (epidermis)
ECM - serves to adhere the basal part of epithelial cell to underlying basement
membrane (BM)