Epithelial Tissue Cells

Avascular

(absence of blood vessels) obtain nutrients from deeper tissues.

Epithelia

layers of cells that cover internal and external surfaces

Apical surface

side of the tissue that is exposed to the environment or an internal chamber/passageway

Cilia

hair-like structures on an apical surface

Microvilli

increase surface area for absorbtion

Basement membrane

protein fibers that connect epithelium to underlying connective tissue

Avascular (absence of blood vessels)

obtain nutrients from deeper tissues

Exocrines

secretions that are discharged onto the epithelial surface

Endocrines

secretions that are released into surrounding tissues

Simple

single layer of cells

Stratified

several layers of cells

Squamous

thin and flat

Cuboidal

cube-shaped in neat rows

Columnar

rectangular

Simple Squamous Epithelial

single layer of thin, flat cells

Simple Cuboidal Epithelial

single layer/row of cube-shaped cells

Simple Columnar Epithelial

single layer of rectangular cells

Stratified Squamous Epithelial

many layers of flat cells (most common)

Stratified Cuboidal Epithelial

2 layers of square-shaped cells

Stratified Columnar Epithelial

multiple (2-5) layers of rectangular cells

Pseudostratified Ciliated Columnar Epithelial

1 layer of rectagular cells (but looks like 2 or more) and has cilia on apical surface

Transitional Epithelial

many layers of rounded, teardrop shaped cells

Merocrine (Eccrine)

Cells - in glands - that undergo exocytosis (create vesicles to release secretion)

Apocrine

Cells - in glands - that partially dissolve to release/discharge secretion

Holocrine

Cells - in glands - that entirely distegrate to release secretion