What in the Cell Are
You Talking About?
An Introduction to the Fundamental
Epithelial Cells of the Human Body
Opening Questions:
1. List the three (3) primary shapes of human
epithelial cells.
2. Where in the human body would one find
transitional epithelium?
3. What type of epithelial cell is our skin?
Objectives of Lesson
• Recognize the various types of epithelial cells
found in the human body
• Identify various shapes of epithelial cells
• Identify characteristics of epithelial cells
• Identify significant parts of each cell
• Determine tissues associated with cells based on
specific morphology
The Human Body
Tissue -
Group of similar cells
and their intercellular
substance that performs
a specialized function.
Histology - The study of tissues
Overview of 4 Basic Tissue Types:
–Epithelial: tissues that cover the body’s surfaces,
lines the body cavities, hollow organs, ducts and
houses glandular cells
–Connective: protects, supports the body and
organs, binds organs together, stores energy
reserves as fat and produces immunity
–Muscle: movement of tissue
-Nervous: initiates and transmits nerve impulses
that coordinate body activity
Epithelium
• Background:
– The term "epithelium" comes from the Greek roots
"epi-" which means "upon" and "thele" = "breast," and
originally meant only the skin on the breast,
particularly around the nipple.
Epithelial Tissue
•Characteristics:
–Epithelial tissue covers surfaces with an
uninterrupted layer of cells.
-Epithelial cells are attached to one another.
–Intercellular spaces in epithelium are small.
–Epithelial cells are polarized.
-Epithelial cells are separated from the
underlying tissue by a basement membrane.
Cellular Shapes
Squamous: flat and attached together similar to tiles
Cuboidal: cube or hexagonal shaped
Produce secretions (sweat, enzymes, etc.)
Able to absorb (intestinal tract)
Columnar: tall, narrow, cylindrical
protection of underlying tissue- specialized for
secretion and absorption
Can be ciliated
Transitional: vary in shape
Flat to columnar due to stretching of the associated
tissue
Arrangement of Layers:
-Simple: single layer of cells found in areas
where passive and active transport are needed
Cellular examples:
a. squamous
b. cuboidal
c. columnar
Arrangement of Layers:
-Stratified: two or more layers used for
protection of underlying tissue in areas of
“wear and tear”
Cellular examples:
a. squamous
b. cuboidal
c. columnar
d. transitional
Arrangement of Layers:
-Pseudostratified: single layer of a mixture of
cell shapes; appears to be multi-layered
Cellular examples:
a. columnar
Glandular Epithelium
Primary Function:
- Secretory purposes
-Cells found below the outer
epithelium
a.
Endocrine: ductless glands; hormones
b. Exocrine: secreted into ducts; mucus,
sweat, oil and digestive enzymes
Now, let’s take a look…
Simple Squamous Epithelium
• Characteristics:
– Single Layered
– Oblong, polyhedralshaped with a prominent
nucleus
• Examples:
– Bowman’s capsule in
kidney
– Alveoli of the lung
Simple Cuboidal Epithelium
• Characteristics:
– Shaped like a cube
– Single layer
• Examples:
– Collecting tubules of
kidney
– Ducts of many glands
– Ciliary body of eye
Simple Columnar Epithelium
• Characteristics:
– Long and thin (columns)
– Single layer
• Examples:
– Mucous membrane of
stomach
– Large and small bowels
– Small bronchi of
respiratory system
Stratified Squamous Epithelium
• Characteristics:
– Oblong, polyhedralshaped with a prominent
nucleus
– stacked in symmetrical
layers
– Keratinized and nonkeratinized
• Examples:
– Epidermis of skin
– Mucous membranes
(esophogus)
Stratified Cuboidal Epithelium
• Characteristics:
– Cube-shaped
– Found in layers
• Examples:
– Ducts of sweat glands
found throughout the
body
– Sebaceous glands of skin
Stratified Columnar Epithelium
• Characteristics:
– Rare
– Shaped liked columns
– Stacked on each other in
symmetrical layers
• Examples:
– Pharynx
– Larynx
– Urethra
Pseudostratified Columnar Epithelium
• Characteristics:
– Ciliated
– Stacked hap-hazardly in
layers of columns
• Examples:
– Tracheal mucosa of
airways
Transitional Epithelium
• Characteristics:
– Vary in shape: cuboidal
and squamous
– have the capacity to
stretch and flatten
• Examples:
– Renal calyces and pelvis
– Ureter
– Urinary Bladder
Test Time!!!
SIMPLE COLUMNAR EPITHELIUM
PSEUDOSTRATIFED CILIATED COLUMNAR EPITHELIUM
SIMPLE SQUAMOUS EPITHELIUM
STRATIFIED SQUAMOUS EPITHELIUM
TRANSITIONAL EPITHELIUM
SIMPLE CUBOIDAL EPITHELIUM
Citations
Illustrations:
www.psbc.org/education/hematology/basics/cell.htm
www.users.tpg.au/users/amcgann/body/
www.echiropractic.net/what_is_a_subluxation.htm
www.webschoolsolutions.com/patts/systems/muscles.htm
www.bweems.com/sccafx.html
www.lima.ohio-state.edu/biology/epithelial_tissue.htm
www.unomaha.edu/~swick/2740epithelium.html#cub