Epithelial Tissues

Question 1

Role of epithelial tissues?

Answer 1

Selective diffusion
Absorption
Secretion
Physical protection
Containment

Question 2

Epithelial cells are closely bound to one another by?

Answer 2

Cell junctions

Question 3

Role of epithelial cell junctions?

Answer 3

Provide physical strength

Mediate exchange of “information” and metabolites

Question 4

Epithelial are supported by…?

Answer 4

Basement membrane

Question 5

Role of basement membrane

Answer 5

Separate epithelia from underlying support tissues

Question 6

How is epithelia classified?

Answer 6

1. Number of cell layers (simple vs stratified)
2. Cell shape (squamous, cuboidal, columnar)
3. Presence of surface specializations (cilia, villi, microvilli)

Question 7

Where is simple squamous epithelium found?

Answer 7

Lung (pleural), heart (pericardial), or abdominal (peritoneal) cavities

Question 7

Where is simple squamous epithelium found?

Answer 7

Lung (pleural), heart (pericardial), or abdominal (peritoneal) cavities

Question 8

What is the function of simple squamous epithelium?

Answer 8

Passive transport of either gases or fluids

Question 9

Where is simple cuboidal epithelium found?

Answer 9

On small ducts and tubules

Question 10

Function of simple cuboidal epithelium?

Answer 10

Has excretory, secretory, or absorptive functions

Question 11

Where is simple columnar epithelium found?

Answer 11

highly absorptive surfaces like the small intestine

Question 12

What is the function of simple columnar epithelium?

Answer 12

Absorption and secretion

Question 13

What is the function of simple columnar ciliated epithelium?

Answer 13

Cilia move in a wave-like manner to propel fluid or minute particles

Question 14

Where is pseudostratified columnar ciliated epithelium found?

Answer 14

Large airways in the respiratory tract (which is why its also known as respiratory epithelium)

Question 15

Why is respiratory epithelium called “pseudostratified”

Answer 15

All cells lie on one basement membrane but the nuclei are on different levels

Question 16

What is the main function of stratified epithelia?

Answer 16

Protection

Question 17

Where is stratified squamous epithelium located?

Answer 17

Oral cavity, pharynx, esophagus, anal canal, uterine cervix, and vagina

Question 18

Where is keratinized stratified squamous epithelium found? How does the keratin help?

Answer 18

Found on epithelial surface of skin (epidermis). Helps withstand constant abrasion and desiccation

Question 19

Where is stratified cuboidal epithelium located?

Answer 19

Lines larger excretory ducts (eg. salivary glands)

Question 20

Where is transitional epithelium located? What is its other name?

Answer 20

Urinary tract, urothelium

Question 21

Where is transitional epithelium located? What is its other name?

Answer 21

Urinary tract, urothelium

Question 22

What makes transitional epithelium unique?

Answer 22

Has both features from stratified cuboidal and stratified squamous epithelium

Question 23

What are the three types of cell junctions?

Answer 23

Occluding (tight) junctions, Adhering junctions, communicating (gap or nexus) junctions

Question 24

What is the role of tight junctions?

Answer 24

Seal intercellular spaces and prevent migration of "floating" membrane proteins

Question 25

What is the role of adhering junctions?

Answer 25

Tightly bind constituent cells of epithelium together and act as anchorage sites for cytoskeleton of each cell

Question 26

What are the types of adhering junctions and their respective roles?

Answer 26

Zonula adherens - forms a continuous band and provides structural reinforcement Desmosomes - provide stability and strength

Question 27

What is the role of the communicating junctions?

Answer 27

Permits passage of small molecules between adjacent cells

Question 28

What is the role of the communicating junctions?

Answer 28

Permits passage of small molecules between adjacent cells

Question 29

What are the luminal surface specializations?

Answer 29

Cilia, microvilli, stereocilia

Question 30

What is the structure and role of cilia?

Answer 30

Structure: long, motile structures, has a central core axoneme made of 20 microtubules arranged as a central pair surrounded by nine peripheral doublets. Each complete tubule has arms made of dynein that extend towards incomplete tubule of adjacent doublet and towards the central microtubule pair. Role: moves in a wave-like motion to propel surface films of mucus or fluid in a consistent direction

Question 31

What is the structure and role of microvilli?

Answer 31

Structure: minute finger-like projections, cytoplasmic core of each microvillus has fine actin filaments that insert into terminal web. Terminal web anchored to zonula adherens Role: increase surface area available for absorption

Question 32

What is the structure and role of stereocilia?

Answer 32

Structure: extremely long microvilli, internal structure is a filamentous skeleton, found in small numbers in parts of the male reproductive tract Role: facilitate absorption

Question 33

What are the basal surface specializations?

Answer 33

hemidesmosomes

Question 34

Role of hemidesmosomes

Answer 34

Means of anchorage of cell via its cytoskeleton to basement membrane + underlying support tissues

Question 35

What are exocrine glands?

Answer 35

glands that discharge secretory product via duct onto epithelial surface

Question 36

What are endocrine glands?

Answer 36

ductless glands with secretory products that diffuse directly into the bloodstream

Question 37

What's the difference between a simple and compound gland?

Answer 37

Simple glands don't have a branched duct. Compound branches do have a branched duct

Question 38

What are the types of secretion from exocrine glands?

Answer 38

Eccrine - mainly proteins secreted via exocytosis Apocrine - discharge of membrane-bound vesicles containing secretory product, mainly lipids Holocrine - disintegration of secretory cell to release secretory product

Question 39

Secretory products of some exocrine glands are embraced by contractile cells called ______

Answer 39

Myoepithelial cells

Question 40

The secretory products of endocrine glands are called hormones. True or False?

Answer 40

True

Question 41

Endocrine gland products only affect activity locally. True or False?

Answer 41

False, controls activity of cells and tissues far removed from site of secretion

Question 42

How do endocrine glands release spread hormones?

Answer 42

Via the network of small blood vessels that surround them