Epithelial Tissue and Epidermis Vocabulary

Epithelial Tissue

Covering and lining tissue that exhibits polarity with apical (top) and basal (bottom) surfaces, receiving oxygen and nutrients via diffusion from blood vessels in deeper tissue.

Basal Surface

The bottom surface location of epithelial tissue.

Apical Surface

The top surface location of epithelial tissue.

Basement Membrane

A connective tissue structure that lies at the basal surface of epithelial tissue.

Lumen

The inner open space or cavity within a hollow structure of the body, allowing for transportation and movement of substances.

Simple Epithelium

A classification of epithelium composed of a single layer of cells.

Stratified Epithelium

A classification of epithelium composed of several layers of cells.

Simple Squamous Epithelium

Epithelial tissue consisting of thin, scale-like cells specialized for rapid diffusion and filtration of chemical compounds, found in alveoli (air sacs) of the lungs.

Squamous Cell

A thin, flattened, scale-like epithelial cell shape.

Endothelium

A type of simple squamous epithelium that lines the heart.

Mesothelium

A type of simple squamous epithelium that lines body cavities.

Simple Cuboidal Epithelium

Epithelial tissue consisting of cube-shaped cells with round central nuclei, specialized for secretion and absorption.

Simple Columnar Epithelium

Epithelial tissue consisting of tall column-like cells with oval-shaped nuclei, highly active in the absorption and secretion of molecules.

Goblet Cells

Mucus-secreting cells located within the stomach lining that protect the stomach from corrosive stomach acid ($HCl$).

Pseudostratified Ciliated Columnar Epithelium

A single layer of irregular-shaped, differently sized columnar cells with nuclei at different levels where all cells touch the basement membrane, though not all reach the apical surface.

Mucociliary Escalator

The coordinated beating of cilia in the respiratory system that moves mucus towards the throat to be swallowed or expelled, also called mucociliary clearance.

Stratified Squamous Epithelial Tissue

The most common type of stratified epithelia, whose superficial layer is covered in dead cells filled with keratin.

Keratin