Histology I
Ferdinand Gomez
Department of Medical Education
Objectives
• Describe the basic mechanisms of tissue staining and compare
and contrast different types of staining
• Name and list the structural and functional characteristics of
various epithelia as applied to the gastric pits, intestinal glands
and the filtration slit diaphragm
• Contrast serous and mucous secretion
• Recognize the structural and functional classification of the
exocrine glands
Histological Methods:
Tissue preparation
• Fixation-permanent preserve specimen
• Postfixation
• Section staining
• TEM vs SEM
Stain:
Hematoxylin & Eosin
• Nuclei: blue
• Pink/red: cytoplasm
• Pink: collagen
Stain:
Periodic Acid-Schiff
• Deep red/magenta: G cells
• Pink: brush borders
Stain:
Weigert’s
• Elastic fibers
• Blue/black: elastic
fibers
• Pink: residual
Stain:
Mallory-Azan
• Hyaline: deep blue
• RBC: red
Stain:
Wright’s
• Blood cells
• Cell: bluish/purple
(nucleus)
• Cell: bluish/gray
(cytoplasm)
• Red/pink: RBCs
Stain:
Silver & Gold
• Blue-black: fibers &
neurofibrils
• Colorless background
Epithelial Tissue
 Occurs in the body as:
Covering, lining, glandular epithelium
 Functions include:
Protection, absorption, filtration, secretion
Epithelial Tissue Characteristics
 Composed of close packed cells
 Tiny amount of extra-cellular material in between
 Form continuous sheets
 Avascular
 Domains: apical, lateral, base
Figure 04.co
Epithelial Classification
Number of layers:
• Simple (single cell) layer for absorption,
filtration, & thin barrier
• Stratified (two or more) layers common in high
abrasion areas
Epithelial Classification
Shape:
• Squamous
• Cuboidal
• Columnar
• Nuclear shape conforms to cell shape
Simple Epithelium
 Squamous
 Cells laterally flattened
 Located in areas of filtration/rapid diffusion
Simple Epithelium
Endothelium
 Provides frictionless lining
 Blood vessels, heart chambers
Simple Epithelium
Mesothelium
 Epithelium found lining walls and organs
Simple Epithelium
Cuboidal
 Spherical nuclei
 Absorption and secretion
 Kidney tubules, secretory ducts
Simple Epithelium
Columnar
 Single layer of tall cells aligned in rows
 Some have cilia
 Absorption & secretion
Simple Epithelium
Pseudostratified Columnar
 Cells vary in height
 Absorption & secretion
Filtration Slit Diaphragm
Intestinal glands (Crypts)
Stratified Epithelium
Squamous
 Most widespread (in areas of wear and tear)
 Superficial cells less viable than deep cells
 Keratinized vs. Non-keratinized
Stratified Epithelium
Cuboidal
 Larger gland ducts
 Sweat glands
 Mammary glands
Stratified Epithelium
Columnar
 Rare tissue
 Forms large gland ducts
 Male urethra
Stratified Epithelium
Transitional
 Basal cells are cuboidal/columnar
 Apical cells vary in shape according to distension of organ
Glandular Epithelium
Secretion Type
•
Secretion type:
serous, mucus,
mixed
Exocrine Glands Classification:
Modes of Secretion
Merocrine
Holocrine
Apocrine
Ceruminous
www.anatomyatlases.org/.../Images/plate142.jpg
Mammary
Thank you!