Epithelium/ Cell Surface

Question 1

What are the two main types of epithelial tissue?

Answer 1

Surface epithelium and some solid organs

Question 2

Where is surface epithelium found?

Answer 2

Lining the surfaces of the body and the cavities within the body

Question 3

What are the main functions of epithelial tissues?

Answer 3

Forming protective barriers, regulation and exchange of molecules between compartments, synthesis and secretion of glandular products, special sensation, and contractile component of myoepithelial cells

Question 4

What are the major characteristics of surface epithelia?

Answer 4

Formation of a continuous sheets with 1+ cell layers, bound to adjacent cells by cell junctions, supported by basement membrane, polarization of cells

Question 5

Which surface of the surface epithelial cell faces towards the lumen?

Answer 5

Apical surface

Question 6

What are the two major components of the basement membrane?

Answer 6

Basal lamina and reticular lamina

Question 7

What component of the basal lamina are large glycoproteins that form a lace like sheet and held in place by integrins?

Answer 7

Laminin

Question 8

What type of collagen is associated with the laminin of the basal lamina?

Answer 8

Type IV collagen

Question 9

What are the glycosylated proteins that link laminin and type IV collagen sheets in the basal lamina?

Answer 9

Entactin and perlecan

Question 10

What is the origin of the basal lamina?

Answer 10

It is secreted by the epithelial cells

Question 11

What is the origin of the reticular lamina?

Answer 11

It is secreted by the underlying connective tissue

Question 12

What are the components of the reticular lamina? What types of collagen make them?

Answer 12

Reticular fibers (type III) and anchoring fibrils (type VII)

Question 13

By what mechanism do metabolites and oxygen cross through the surface epithelial layer?

Answer 13

Diffusion

Question 14

What is the type of epithelium consists of only a single layer of cells? What is the typical purpose for this type of epithelia?

Answer 14

Simple epithelia; usually found at interfaces involving diffusion, absorption and/or secretion

Question 15

What type of epithelia consists of 2 or more layers?

Answer 15

Statified epithelium

Question 16

What are the classic intermediate filaments of epithelial cells?

Answer 16

Keratins

Question 17

What is the main protein of tight junctions? What is its function?

Answer 17

Claudin; changes permeability factor

Question 18

Where on the cell are tight junctions found?

Answer 18

At the luminal end of lateral cell membrane

Question 19

What is the most apical lateral junction between cells?

Answer 19

Tight junctions

Question 20

What is the major structural protein in zona adherens that crosses the intracellular space and attahes to actin filaments in the cell?

Answer 20

Cadherin

Question 21

What type of junction joins terminal webs of one cell to neighboring cells?

Answer 21

Zona adherens

Question 22

To what kind of filament do desmosomes attach?

Answer 22

Intracellular keratin filaments

Question 23

What type of adhering junction forms dense attachment plaques?

Answer 23

Desmosomes (heidesmosomes also form plaques)

Question 24

What is the function of hemidesmosomes?

Answer 24

Links cells to underlying basement membrane

Question 25

What is the major connecting protein in hemidesmosomes?

Answer 25

Integrins

Question 26

What are the functions of communicating (gap) junctions?

Answer 26

Passage of ions and small molecules between neighboring cells and for intercellular signaling

Question 27

What is the main protein utilized in communicating junctions?

Answer 27

Connexins

Question 28

What are the three types of apical epcializations of epithelial cells?

Answer 28

Cilia, microvilli, stereocilia

Question 29

Where are epithelial cells with motile cilia likely to be found?

Answer 29

Respiratory tract, reproductive tracts, ependymal cells

Question 30

What is the structure of a cilium?

Answer 30

20 microtubules arranged as a central doublet surrounded by 9 peripheral doublets

Question 31

How are the peripheral doublets of microtubules in cilia linked and attached to the central core?

Answer 31

Linked via nexin and attached to the central core by radial spokes

Question 32

What is the function of microvilli?

Answer 32

Increasing surface area of the apical portion of the cell

Question 33

What is the structural composition of microvilli?

Answer 33

Actin filaments attached to the terminal web

Question 34

What are the structural components of stereocilia?

Answer 34

Actin filaments

Question 35

What is the purpose of stereocilia?

Answer 35

Special sensation

Question 36

What kind of gland secretes contents into ducts?

Answer 36

Exocrine glands

Question 37

Secretions from what kind of glands travel in the bloodstream?

Answer 37

Endocrine glands

Question 38

What method of glandular secretion involves the process of exocytosis?

Answer 38

Merocrine (eccrine)

Question 39

What method of glandular secretion involves the discharge of free unbroken vesicles with product inside?

Answer 39

Apocrine

Question 40

What method of glandular secretion involes the discharge of the whole cell to release product?

Answer 40

Holocrine

Question 41

The secretory proteions of glands are sometimes surrounded by what kind of specialized epthelial cells?

Answer 41

Myoepithelial cells

Question 42

What type of epithelium is most appropriate for absorption?

Answer 42

Simple columnar