Lect 02 107 2025 epithelia handout (1)

Question 1

What are the general features of epithelial tissues?

Answer 1

Covers body surface, lines hollow organs, cavities and ducts, forms the glands of the body.

Question 2

What are the key functions of epithelial tissues?

Answer 2

• Selective Barriers
• Secretory
• Protective

Question 3

What is the structure of epithelial cells?

Answer 3

Arranged in continuous sheets as single or multiple layers.

Question 4

What types of cell junctions are found in epithelial tissues?

Answer 4

• Tight junctions
• Adherens junctions
• Gap junctions
• Desmosomes
• Hemidesmosomes

Question 5

What is the function of tight junctions?

Answer 5

Prevent migration of proteins between apical and lateral surfaces, maintain cell polarity.

Question 6

What proteins are key components of tight junctions?

Answer 6

• Claudins
• Occludins

Question 7

What are adherens junctions also known as?

Answer 7

Belt desmosomes or adhesion belts.

Question 8

What is the role of cadherins in adherens junctions?

Answer 8

Span the gap and link to actin via catenins.

Question 9

What is the main function of desmosomes?

Answer 9

Resist shearing forces and provide structural integrity.

Question 10

What connects cells at desmosome junctions?

Answer 10

Cadherin binds to Desmoplakin, linking to Keratin.

Question 11

What allows the passage of small molecules in gap junctions?

Answer 11

Connexin protein molecules form connexons or hemichannels.

Question 12

What do hemidesmosomes connect?

Answer 12

Epithelia to the basement membrane.

Question 13

What are the two parts of the basement membrane?

Answer 13

• Basal Lamina
• Reticular Lamina

Question 14

What is the function of the basement membrane?

Answer 14

• Supports overlying epithelium
• Provides a migration surface during growth and healing
• Acts as a physical barrier
• Participates in filtration in kidneys

Question 15

What are the two main types of epithelial tissue?

Answer 15

• Covering and Lining Epithelia
• Glandular Epithelia

Question 16

What is the function of covering epithelia?

Answer 16

Cover exposed surfaces and internal cavities.

Question 17

What distinguishes glandular epithelia?

Answer 17

Secretory cells predominate.

Question 18

What are the two types of glands formed by glandular epithelia?

Answer 18

• Exocrine
• Endocrine

Question 19

What do exocrine glands secrete?

Answer 19

Onto external surfaces and into passages (ducts).

Question 20

What do endocrine glands release?

Answer 20

Hormones or precursors into interstitial fluid.

Question 21

How are covering and lining epithelia classified?

Answer 21

According to the arrangement and shapes of cells.

Question 22

What are the arrangements of cells in epithelial tissues?

Answer 22

• Simple: single layer
• Stratified: two or more layers
• Pseudostratified: appears to have multiple layers

Question 23

What are the shapes of epithelial cells?

Answer 23

• Squamous: flat and thin
• Cuboidal: about as tall as wide
• Columnar: taller than wide
• Transitional: changes shape

Question 24

What are examples of simple squamous epithelium locations?

Answer 24

• Bowman’s capsule of kidney
• Lining of blood vessels
• Mesothelium

Question 25

What is the appearance of simple cuboidal epithelium?

Answer 25

Cuboidal or hexagonal boxes.

Question 26

Where is simple columnar epithelium commonly found?

Answer 26

* Lines gut mucosa * Ducts of many glands * Gall bladder

Question 27

What is a characteristic feature of ciliated simple columnar epithelium?

Answer 27

Contains goblet cells and moves materials.

Question 28

What is the function of stratified squamous epithelium?

Answer 28

Protection against abrasion and microbes.

Question 29

What distinguishes keratinized stratified squamous epithelium?

Answer 29

Apical cells are packed with keratin.

Question 30

Where can non-keratinized stratified squamous epithelium be found?

Answer 30

* Mouth * Throat * Tongue * Esophagus * Vagina

Question 31

What is the function of non-keratinized stratified squamous epithelium?

Answer 31

Protection from abrasion and defense from microbes. ## Footnote Examples include mouth, throat, tongue, esophagus, anus, and vagina.

Question 32

Where is keratinized stratified squamous epithelium typically found?

Answer 32

Skin in dry trauma areas. ## Footnote This type of epithelium is adapted to resist mechanical stress.

Question 33

What characteristic distinguishes pseudostratified columnar epithelium?

Answer 33

Nuclei at different levels, giving an appearance of multiple layers. ## Footnote It is actually a simple epithelium.

Question 34

What are the two specialized subtypes of pseudostratified columnar epithelium?

Answer 34

* Pseudostratified ciliated columnar epithelium * Pseudostratified non-ciliated columnar epithelium

Question 35

What is the function of ciliated pseudostratified columnar epithelium?

Answer 35

Secretion of mucus and movement of mucus. ## Footnote Found in most of the upper airways.

Question 36

Fill in the blank: Simple squamous epithelium is found in the _______.

Answer 36

[endothelium lining blood vessels]

Question 37

What are the examples of simple cuboidal epithelium?

Answer 37

* Pancreas ducts * Parts of kidney ducts * Secretory chambers of thyroid * Lens surface * Pigmented epithelium at posterior of retina

Question 38

What is a key example of non-ciliated simple columnar epithelium?

Answer 38

Gastrointestinal tract from stomach to anus. ## Footnote Also found in ducts of many glands and the gall bladder.

Question 39

What distinguishes keratinized from non-keratinized stratified squamous epithelium?

Answer 39

Keratinized contains keratin; non-keratinized does not. ## Footnote Keratinized epithelium is found in skin, while non-keratinized is in moist areas.

Question 40

What is the primary function of glandular epithelia?

Answer 40

Secretion.

Question 41

How are glands classified based on secretion pathways?

Answer 41

* Endocrine glands: secrete directly into blood * Exocrine glands: secrete into ducts

Question 42

What are examples of endocrine glands?

Answer 42

* Pituitary * Pineal * Thyroid * Parathyroid

Question 43

What are examples of exocrine glands?

Answer 43

* Sweat glands * Salivary glands * Oil glands * Wax glands * Pancreas

Question 44

What is a single-cell exocrine gland example?

Answer 44

Goblet cells. ## Footnote Goblet cells are a type of mucous gland.

Question 45

What are the three characteristics used to describe the structure of multicellular exocrine glands?

Answer 45

* Structure of duct * Structure of secretory area * Relationship between the two

Question 46

True or False: All multicellular glands use the term 'branched' to describe their structure.

Answer 46

False.

Question 47

What type of epithelium is found in the bladder?

Answer 47

Stratified transitional epithelium. ## Footnote Also found in some parts of the ureter and urethra.