Epithelium

Question 1

name the functions of epithelium (7)

Answer 1

protection, absorption, secretion (glands), transcellular transport, sensation, contractility

Question 2

components of basement membrane (3)

Answer 2

basal lamina, reticular fibers, hemidesmosomes

Question 3

what composes the basal lamina (3)

Answer 3

type IV collagen , laminin, proteoglycans

Question 4

what are reticular fibers made from

Answer 4

type III collagen

Question 5

which cells generate hemidesmosomes and basal lamina?

Answer 5

epithelial cells

Question 6

which cells generate reticular fibers?

Answer 6

the underlying connective tissue

Question 7

what is unique about the basement membrane in renal glomerular cells?

Answer 7

two basal laminae

Question 8

functions of basal lamina (3)

Answer 8

gives polarity to cells resting on it, forms a boundary between tissues, attaches epithelial to connective tissue

Question 9

what is important about the function of basal lamina forming a boundary between tissues?

Answer 9

restricts the epithelial cells from entering the connective tissue and protects against tumor invasion/mets

Question 10

why are epithelial cells associated with increased risk of cancer, especially later in life?

Answer 10

continuous renewal of epithelial cells makes them susceptible to malignancy

Question 11

what are the 3 general regions of an epithelial cell?

Answer 11

apical, lateral, basal

Question 12

where do epithelial cells get their nutrients?

Answer 12

epithelial cells are avascular, get nutrients from underlying connective tissue

Question 13

what gives epithelial cells their “polyhedral” shape?

Answer 13

little extracellular space (tight packing)

Question 14

what is “lamina propria”?

Answer 14

type of connective tissue

Question 15

where is lamina propria found?

Answer 15

digestive, respiratory and urinary systems

Question 16

describe tight junctions (zonula occludens)

Answer 16

near the apical side of the cell, prevent passive flow of material between epithelial cells

Question 17

name some pathogens that attack the zonula occludens

Answer 17

h. pylori and c. perfinges

Question 18

describe the zonula adherens

Answer 18

hold adjacent cells together, usually under ZO, encircle entire cell

Question 19

describe macula adherens

Answer 19

cell-to-cell attachments, made of intermediate filaments, facilitated by cadherins (CAMs)

Question 20

what is another name for macula adherens?

Answer 20

desmosome

Question 21

in which types of cells would you expect lots of macula adherens?

Answer 21

epithelial exposed to high physical stress

Question 22

describe gap junctions

Answer 22

patch of connexons that are intracellular channels for the flow of substances between cells

Question 23

what are gap junctions most permeable to?(3)

Answer 23

cAMP, cGMP, Ca2+

Question 24

what are terminal bars?

Answer 24

appearance of ZO and ZA under LM is described as “terminal bar”

Question 25

what are hemidesmosomes?

Answer 25

part of basement membrane, connect cell to basal lamina, binding is facilitated by integrins

Question 26

what is the primary purpose of microvilli?

Answer 26

increase SA for absorption

Question 27

what are microvilli composed of?

Answer 27

actin core that is linked to the terminal web via intermediate filaments

Question 28

what is the terminal web composed of?

Answer 28

web of microfilaments at the apical end of a cell

Question 29

describe the "brush border"

Answer 29

thick layer of glycocalyx associated with microvilli, contains digestive enzymes

Question 30

what are stereocilia?

Answer 30

longer, more branched microvilli

Question 31

what are the main functions of stereocilia?

Answer 31

absorption (epididymis) and mechanosensation (inner ear)

Question 32

what are stereo cilia composed of?

Answer 32

actin bundles and glycocalyx coats

Question 33

what is the primary function of cilia?

Answer 33

movement

Question 34

what are cilia composed of?

Answer 34

microtubules (9+2 arrangement) anchored to basal bodies in cytoplasm

Question 35

what determines the classification of an epithelial tissue?

Answer 35

the TOP layer

Question 36

define "simple"

Answer 36

one layer of cells

Question 37

describe squamous cells

Answer 37

flat, thin cells with a pancake shaped nucleus

Question 38

where are squamous cells commonly found?

Answer 38

typically line cavities and vessels where the specialize in transport processes

Question 39

describe cuboidal cells

Answer 39

equally tall and wide

Question 40

why do cuboidal cells contain lots of mitochondria?

Answer 40

they tend to specialize in active transport

Question 41

describe columnar cells

Answer 41

taller than they are wide

Question 42

what is the typical function of columnar cells?

Answer 42

absorprtion (with microvilli)

Question 43

what organelles are abundant in columnar cells? (2)

Answer 43

mitochondria, transport organelles (vesicles)

Question 44

define "stratified"

Answer 44

multiple cell layers

Question 45

what is the protective function of stratified squamous epithelium?

Answer 45

protects gainst water loss and microorganisms

Question 46

describe "keratinized"

Answer 46

filled with keratin, loss of organelles, helps to block water loss and prevent pathogen entry

Question 47

describe "non-keratinized"

Answer 47

allow for movement of water

Question 48

where would you expect to find keratinized epithelium?

Answer 48

external structures (skin)

Question 49

where would you expect to find non-keratinized epithelium?

Answer 49

cells lining interior cavities

Question 50

describe "transitional" epithelium

Answer 50

superficial layer of "dome-like"/"umbrella" cells

Question 51

where is transitional epithelium located?

Answer 51

lumens of urinary system

Question 52

what happens to the appearance of transitional epithelial cells when the vessel they line is full?

Answer 52

they appear more flat

Question 53

described pseduostratified

Answer 53

only one cell layer, but it looks like it is stratified because the nuclei are at different levels and not all of the cell penetrate to the apical side of the cell

Question 54

name a unicellular gland

Answer 54

goblet cell

Question 55

what do goblet cells secrete?

Answer 55

mucin by exocytosis (mucin then interacts with water in the lumen to form mucus)

Question 56

what is the typical appearance of a goblet cell?

Answer 56

RER localized to basal side, nucleus and large golgi, apical end filled with mucins in sec granules

Question 57

contrast endocrine vs. exocrine glands

Answer 57

endocrine glands secrete hormones into blood, exocrine glands have ducts and secrete substances onto surfaces

Question 58

define "simple gland"

Answer 58

unbranched duct

Question 59

name the types of simple glands discussed (5)

Answer 59

tubular, branched tubular, coiled tubular, acinar, branched acinar

Question 60

define "compound gland"

Answer 60

branched duct

Question 61

name the types of compound ducts discussed (3)

Answer 61

tubular, acinar, tubuloacinar

Question 62

describe a merocrine gland

Answer 62

secretes products via exocytosis

Question 63

describe a holocrine gland

Answer 63

secretion via cell death and product release

Question 64

describe an apocrine gland

Answer 64

secretion via loss of a large membrane-enclosed portion of apical cyptoplasm

Question 65

give and example of a merocrine gland

Answer 65

salivary gland

Question 66

give and example of a holocrine gland

Answer 66

sebaceous gland

Question 67

give and example of a apocrine gland

Answer 67

mammary gland

Question 68

define dysplasia

Answer 68

change in cell shape/size/organization (pre-cancerous)

Question 69

define hyperplasia

Answer 69

increase in number of cells

Question 70

define hypertrophy

Answer 70

increase in size of cells

Question 71

define hypoplasia

Answer 71

decreased number of cells

Question 72

define hypotrophy

Answer 72

decreased size of cells

Question 73

define pleomorphism

Answer 73

many different cell sizes/shapes

Question 74

define anaplasia

Answer 74

loss of differentiation of a given cell type (neoplastic cells are less differentiated than expected)

Question 75

define metaplasia

Answer 75

change from one cell or tissue type to another secondary to physical or chemical stress

Question 76

describe Barrett's Esophagus

Answer 76

change in the lower esophagus to a gastric-like epithelium secondary to chronic acid exposure (intestinal metaplasia)

Question 77

define papilloma

Answer 77

benign tumor from surface epithelium

Question 78

define adenoma

Answer 78

benign tumor form glandular epithelium

Question 79

define carcinoma

Answer 79

malignant tumor from surface epithelium

Question 80

define adenocarcinoma

Answer 80

malignant tumor from glandular epithelium

Question 81

how does mitotic activity relate to malignancy

Answer 81

increased mitotic activity, increased malignancy

Question 82

define "invasion"

Answer 82

ability to reach the basal lamina

Question 83

what shape are the nuclei of cuboidal cells?

Answer 83

spherical