Histology

• Light Microscopy (LM) – paraffin embedded, 7 micron sections, specific stains

• Transmission Electron Microscopy (TEM) – plastic embedded, 70 millimicron sections, e-dense stains

• Scanning Electron Microscopy (SEM) – critically point dried, gold coated

Light Microscopy

TEM

SEM

Epithelium

Simple Epithelium

Simple Squamous

Mesothelium

Simple Squamous (Mesothelium) by TEM

Simple Squamous – Endothelium (En)

Simple Squamous – Endothelium (Ed) by TEM

Capillary (endothelial cell) by TEM

Simple Cuboidal Epithelium (longitudinal section)

Simple Cuboidal (cross section)

Simple Cuboidal by TEM

Simple Columnar with Goblet Cells

Simple Columnar (cross section)

with Goblet Cells (arrow)

Goblet Cell with PAS stain (red)

Simple Columnar with Goblet Cells

(Mu) by TEM

Simple Columnar (AC) with Goblet Cells

(GC) by SEM

Simple Columnar mucus

secreting

Simple Columnar mucus

secreting

Epithelium

Stratified Epithelium

Pseudostratified Ciliated Epithelium with Goblet Cells

Pseudostratified Epithelium with Cilia (a) and Goblet Cells (b)

Stratified Squamous non-Keratinized Epithelium

Transitional Epithelium

Transitional Epithelium with rounded binucleated surface cells

Stratified Squamous Keratinized (thin)

Stratified Squamous Keratinized (thick)

Epithelial Cell Junctions

Tight Junctions (Zonula Occludens) by TEM

Tight Junctions (Zonula Occludens) by Freeze Fracture

Gap Junction (Nexus) by TEM

Gap Junction

Connexin moleculesOpen pores for

ions, molecules, etc

2 nM gap between membranes

TEM of Zonula Adherens (red

arrows)

TEM of a Desmosome (blue

arrow)

TEM (colorized) of Adherens Junctions

TEM of a Desmosome with tonofibrils

TEM of a Hemi-Desmosome

Summary of the maintenance of cell shape by junctions and cytoskeletal elements

Glandular Epithelium

Serous Gland with ducts (arrows)

Serous secretory unit (high magnification)

Mucous Gland with duct (arrow)

Mixed Gland with Serous Demilunes (SD)