Epithelial Tissues

Question 1

Definition of Tissues

Answer 1

Definition: A group of cells of similar structure that perform a common function.

Question 2

What are the Basal Surface Features?

Answer 2

Basal lamina
•Noncellular sheet made of proteins
•Functions
- Selective filter
- Scaffolding for new, migrating epithelial cells
• Reticular fibers
• Basement membrane =
- basal lamina + reticular fibers

Question 3

What are the Apical Surface Features?

Answer 3

Microvilli
• Folds of plasma membrane
• Increase surface area to increase absorption or secretion
• Don’t move; smaller than cilia
Cilia
• Whip-like, highly motile extensions of plasma
membrane
• Moves fluid/substances in one direction

Question 4

How do you name Epithelial Tissues?

Answer 4

Epithelial tissue has two part names
• The first name describes the number of cell layers present and the second describes the shape of the cells.
-Example: stratified squamous epithelium

Question 5

What is the first name of epithelial tissues?

Answer 5

• The first describes how many layers
the tissue has
- 1 layer = simple
- 2 or more layers = stratified

Question 6

What is the second name of Epithelial Tissues?

Answer 6

The second name refers to the shapes of
the cells
• Squamous = flat
• Cuboidal = cube-shaped
• Columnar = taller than wide

Question 7

Qualities of Simple Cuboidal Epithelium

Answer 7

• Single layer of cube shaped cells
• Absorption: kidney
• Secretion: some glands

Question 8

Qualities of Simple Columnar Epithelium.

Answer 8

• Single layer of tall cells
• May ore may not have cilia or microvilli
• Absorption: GI tract
• Movement: small bronchi of lungs (cilia move mucus) or uterine tubes (propel ovum)
• Secretion: of mucus

Question 9

Qualities of Pseudostratified Columnar Epithelium.

Answer 9

Pseudostratified Columnar Epithelium
• Single layer of cells of varying heights
• Appear to be multiple layers but only
one
• All cells sit on basement membrane
• Nuclei are at different heights
• Secretion and movement: mucus in
respiratory tract
• Usually ciliated

Question 10

Qualities of Stratified Epithelia

Answer 10

Stratified Epithelia
• Two or more layers
• Basal layer: germinating layer
• Apical layer: oldest cells
• Named by shape of apical layer
• Often associated with protection

Question 11

Qualities of Stratified Squamous Epithelium

Answer 11

Stratified Squamous Epithelium
• Multiple cell layers
• Apical layer flat
• May be keratinized or not
- Keratin is a tough protein (offers protection)
• Protection: epidermis of skin (keratinized); oral cavity and esophagus(nonkeratinized)

Question 12

Qualities of Stratified Cuboidal Epithelium

Answer 12

Stratified Cuboidal Epithelium
• Two layers of cube shaped
cells
• Protection and secretion:
salivary glands

Question 13

Qualities of Stratified Columnar Epithelium

Answer 13

Stratified Columnar Epithelium
• Several cell layers, apical layer
tall
• Not common
• Protection: male urethra
• Secretion: ducts of some glands

Question 14

Transitional Epithelium

Answer 14

• Multiple layers that change shape when stretched
• Look thinner when stretched
• Unique to urinary system; allows for distention when structures fill with urine
• Lines urinary bladder

Question 15

Types of Glands

Answer 15

• All glands are lined by epithelium
Endocrine glands:
• Lack ducts
• Produce hormones which pass into surrounding tissues/blood vessels
Exocrine glands:
• Secrete via ducts into body cavities or onto a body surface

Question 16

What are the exocrine glands?

Answer 16

Unicellular glands
• Example: Goblet cell
- Shaped like a goblet
- Produce mucus
- Found in respiratory and digestive tracts
Multicellular glands
• Two names
• Classified by the structure of their ducts
- Simple (duct is unbranched)
- Compound (duct is branched)
• And the shape of their secretory units
- Tubular (tube shaped)
- Alveolar (spherical)