Epithelial Cell

Epithelial Cells

Tightly packed cells that form continuous sheet-like layers; they protect, secrete, and absorb.

Main Functions of Epithelial Cells

Provide physical barriers, regulate absorption and secretion, and produce or secrete substances such as hormones and enzymes.

Squamous Epithelium

Composed of flat, thin cells.

Cuboidal Epithelium

Composed of cube-shaped cells.

Columnar Epithelium

Composed of tall, narrow cells.

Pseudostratified Epithelium

A single layer of cells that appears stratified because the cells have different heights, but all cells are attached to the basement membrane.

Transitional Epithelium

An epithelium with multiple layers of cells that can change shape depending on the degree of stretching.

Simple Epithelium

Epithelium consisting of a single layer of cells.

Stratified Epithelium

Epithelium consisting of multiple layers of cells.

Basement Membrane

A supporting layer to which epithelial cells are attached.

Epithelial Barrier Function

Protects the body and underlying tissues from pathogens, harmful substances, and physical damage.

Epithelial Absorption

The uptake of substances across epithelial cells.

Epithelial Secretion

The production and release of substances such as hormones, enzymes, and mucus by epithelial cells.

Cilia

Hair-like structures on the surface of some epithelial cells that move substances across the cell surface.

Microvilli

Small projections that increase the cell's surface area for absorption.

Epithelial Cell Specializations

Structures such as cilia and microvilli that help epithelial cells perform specific functions.