Lecture Outline 2
 

 

Epithelia

Illustration 003

 

 

Basic Epithelial Types

Illustration 004

 

1. Covering Epithelia or Lining Epithelia

 

A. Apical Surface (Free Surface)

 

B. Basal Surface (Bounded Surface)

 

2. Glandular Epithelia

 

3. Flow Chart 1 (Classifications of Epithelia) in Workbook on Compact Disk

 

 

Covering Epithelia or Lining Epithelia

 

1. Number of Cell Layers

 

A. Simple Epithelium

 

B. Stratified Epithelium

 

2. Shape of Constituent Cells

Illustration 005

 

A. Squamous Epithelium

 

B. Cuboidal Epithelium

 

C. Columnar Epithelium

 

3. Apical Specialization of Constituent Cells

 

A. Striated Border (Brush Border)
Illustration 006
 
1) Microvilli: Cores of Microfilaments
Illustration 007
 

2) Terminal Web

 

B. Stereocilia

Illustration 008
 

C. Cilia

 

1) Cores of Microtubules
Illustration 009
 

2) Basal Body: Centriole

 

D. Flagella

 

E. Keratinization

Illustration 010
 
1) Fibrous Protein Keratin

 

2) "Dry" Epithelia

 

3) "Moist" Epithelia

 

 

Unclassifiable Epithelia

Illustration 011

 

1. Pseudostratified (Columnar) Epithelium

 

2. Transitional Epithelium

 

A. Contracted (Collapsed) Organ

 

B. Distended (Expanded) Organ

 

 

Other Specializations of Epithelial Cells

 

1. Infolding: Interdigitation

Illustration 012

 

2. Glycocalyx (Cell Coat)

Illustration 013

 

A. Glycoprotein (Glycosaminoglycan)

 

B. Basal Lamina

 

3. Basement Membrane

Illustration 014

 

A. Basal Lamina: Product of Epithelial Cells

 

B. Reticular Lamina: Product of Connective-Tissue Cells

 

 

Intercellular Junctions

 

1. Junctional Configuration

 

A. Zonular Junction: Zonula ("Girdle")

 

B. Fascial Junction: Fascia ("Band")

 

C. Macular Junction: Macula ("Spot")

 

2. Junctional Types

Illustration 015

 

A. Occluding Junction (Tight Junction)

 

B. Intermediate Junction: Microfilaments

 

C. Desmosome

 

1) Intermediate Filaments (Tonofilaments)

 

2) Cytoskeleton

 

D. Communicating Junction (Gap Junction, Nexus)

 

3. Terminal Bar: Junctional Complex

 

4. "Cytoplasmic Bridges"

Illustration 016

 

 

Glandular Epithelia

 

1. Method of Glandular Release

 

A. Exocrine Gland

 

B. Endocrine Gland

 

2. Number of Cells in Glandular Unit

 

A. Unicellular Gland

 

B. Multicellular Gland

 

3. Mechanism of Product Release

 

A. Holocrine Gland: Living or Dead Cells

 

B. Apocrine Gland

 

C. Merocrine Gland: Secretory Exocytosis (Secretion)

 

4. Consistency of Product

 

A. Mucous Gland

 

B. Serous Gland

 

C. Mixed Gland

 

 

Exocrine Glands

Illustration 017

 

1. Unicellular Exocrine Gland: Goblet Cell

 

A. Merocrine Release of Mucous Product

 

B. Mucigen Droplets

 

1) Mucin

 

2) Bounding Membrane

 

C. Mucus

 

2. Multicellular Exocrine Glands

 

A. Primitive Multicellular Exocrine Glands

 

1) Secretory Sheet
Illustration 018
 

2) Intraepithelial Gland: Restriction to Stratified Epithelia and Pseudostratified (Columnar) Epithelia Only

Illustration 019
 

B. Advanced Multicellular Exocrine Glands

 

1) Duct

 

2) Secretory Unit(s)

 

 

Advanced Multicellular Exocrine Glands

 

1. Morphology of Duct

Illustration 020

 

A. Simple Glands

 

1) Simple (No Modifier) Gland: Straight Course

 

2) Simple Coiled Gland: Twisted Course

 

B. Compound Glands

 

2. Morphology of Secretory Unit(s)

 

A. Tubular Glands

 

1) (No Modifier) Tubular Gland: Unbranched Secretory Unit(s)

 

2) Branched Tubular Gland: Branched Secretory Unit(s)

 

B. Alveolar Glands (Acinar Glands)

 

1) (No Modifier) Alveolar Gland: Unbranched Secretory Unit(s)

 

2) Branched Alveolar Gland: Branched Secretory Unit(s)

 

C. Tubuloalveolar Glands (Tubuloacinar Glands)

 

1) (No Modifier) Tubuloalveolar Gland: Unbranched Secretory Unit(s)

 

2) Branched Tubuloalveolar Gland: Branched Secretory Unit(s)

 

 

Secretory Units of Mixed Advanced Multicellular Exocrine Glands

Illustration 021

 

1. Mucous Secretory Units: Mucigen Droplets

 

2. Serous Secretory Units: Zymogen Granules

 

3. Mucous-Serous Secretory Units (Mixed Secretory Units): Mucous Alveoli with Serous Demilunes

Illustration 022

 

 

Endocrine Glands

 

1. Merocrine Release of a Serous Product

 

2. Number of Cells in the Secretory Unit(s)

 

A. Unicellular Endocrine Gland: Enteroendocrine Cell

 

B. Multicellular Endocrine Glands

Illustration 023
 
1) Follicular Gland

 

A) Colloid

 

B) Follicular Epithelium

 

2) Cord-and-Clump Gland

 


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© Michael J. Cavey, 1998-2003
Last Update: 15 December 2002