Epithelium

Question 1

What is epithelium

Answer 1

highly cohesive sheet of cells that lines the cavities of organs, covers or lines body surfaces and forms the functional units of secretory glands.

Question 2

Basic functions of epithelium.

Answer 2

protection sand covering of surfaces
lubrication of surfaces
absorption
secretion 
exchange of substances

Question 3

What surfaces of the body do epithelium line?

Answer 3

All external and internal surfaces of the body. All substances that ever to leave tissues and organs must cross and epithelium.

Question 4

What mechanism do epithelial cells renew?

Answer 4

by mitosis at a variable rate and lack blood supply.

Question 5

how are nutrients delivered to epithelium?

Answer 5

by diffusion from tissue

Question 6

How are the cell layers of epithelium maintained?

Answer 6

Specific cell adhesion molecules and intercellular junctions and the cells are attached or anchored to a connective tissue striation called basal lamina

Question 7

What are the 8 different types of epithelium?

Answer 7

Pseudostratified 
Transitional (urothelium)
simple squamous
simple cuboidal 
simple columnar
stratified squamous
stratified cuboidal 
stratified columnar

Question 8

Characteristics of simple squamous?

Answer 8

single layer of flat cells with spinal-shaped nucleus

Question 9

Function of simple squamous?

Answer 9

lining, exchange, lubrication

Question 10

Location fo simple squamous?

Answer 10

lining of blood vessels (endothelium), lining of body cavities (mesothelium), lining of organs (serosa), lining of respiratory spaces (alveoli) in the lung.

Question 11

Characteristics of simple cuboidal?

Answer 11

single layer of cells of equal height and width with a round centrally placed nucleus

Question 12

Function of simple cuboidal?

Answer 12

absorption; secretion

Question 13

Location fo simple cuboidal?

Answer 13

small ducts of exocrine glands, surface of ovary, kidney tulles, thyroid gland follicles

Question 14

Characteristics of simple columnar?

Answer 14

single layer of cells taller than they are wide with a round or oblong nucleus located centrally or toward the basal region of the cell.

Question 15

Function of simple columnar?

Answer 15

absorption and secretion, protection, lubrication

Question 16

Location fo simple columnar?

Answer 16

lining of gastrointestinal system, lining of gallbladder, lining of some large ducts

Question 17

Characteristics of stratified squamous?

Answer 17

multiple layers of cells with the outermost layer of cells squamous-shaped

Question 18

Function of stratified squamous?

Answer 18

protection and secretion

Question 19

Location of stratified squamous?

Answer 19

epidermis, lining of oral cavity, esophagus and vagina

Question 20

Characteristics of stratified cuboidal?

Answer 20

multiple layers of cells with outermost layer cuboidal-shaped

Question 21

Function of stratified cuboidal?

Answer 21

absorption and secretion

Question 22

Location fo stratified cuboidal?

Answer 22

sweat glands and ducts, larger ducts of exocrine glands

Question 23

Characteristics of stratified columnar?

Answer 23

multiple layer of cells with outermost layer columnar-shaped

Question 24

Function of stratified columnar?

Answer 24

secretion, absorption, and protection

Question 25

Location fo stratified columnar?

Answer 25

largest ducts of exocrine glands and conjunctiva of eye

Question 26

Characteristics of pseudostratified?

Answer 26

although it appears stratified is composed of only one cell layer of vernally columnar cells. ALL cells tough the basement membrane even though they do not all reach the luminal surface. typically have cilia on apical surface.

Question 27

Function of pseudostratified?

Answer 27

section and absorption; lubrication

Question 28

Location of pseudostratified?

Answer 28

lining of trachea, bronchi, nasal cavity, reproductive tract (ductus deferent, oviduct)

Question 29

Characteristics of transitional (urothelium)?

Answer 29

stratified epithelium found exclusively in part of the renal system. the shape of the top layer can change based on dissension of the underlying tissue. Accurate classification depends on knowing where it is found.

Question 30

Function of transitional (urothelium)?

Answer 30

distensibility (capacity to swell as result from pressure inside)

Question 31

Location of transitional (urothelium)?

Answer 31

urethra, bladder, ureters, renal calyces

Question 32

Merocrine/Eccrine

Answer 32

product released by exocytosis from membrane-bound granules or vesicles that fuse with the apical cell membrane (e.g pancreas)

Question 33

Apocrine

Answer 33

product released with a small portion of apical cytoplasm and membrane (e.g mammary gland secretion of mild lipids)

Question 34

Holocrine

Answer 34

the secretory product constitutes the entire cell and its products (e.g sebaceous gland)

Question 35

What are the classifications of cell junctions?

Answer 35

symmetrical junctions or asymmetrical junctions

Question 36

What junctions constitutes symmetrical junctions?

Answer 36

tight junctions desmosomes and gap junctions

Question 37

What junctions constitutes asymmetrical junctions?

Answer 37

hemidesmosomes