Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microanatomy > MA3 - Epithelia > Flashcards

MA3 - Epithelia Flashcards

1
Q

What is an epithelium?

A

sheet of cells that covers a surface, often enclosing a lumen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the two primary functions of an epithelium?

A

semipermeable barrier; protection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define parenchyma.

A

cells that mediate functional aspect of a tissue (i.e. hepatocyte of liver)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Define stroma.

A

cells that serve as support structures of a tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the three distinct surfaces of plasma membranes?

A

apical; lateral; basal (+ basolateral, but it’s not considered a distinct surface)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the function/location of the apical membrane.

A

commonly faces a lumen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe the function/location of the lateral membrane.

A

faces and binds to adjacent epithelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the function/location of the basal membrane.

A

commonly faces underlying connective tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

At which end/surface is the nucleus of a cell found?

A

basal end of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What structure connects the basal surface to the underlying connective tissue?

A

basement membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the two components of the basement membrane?

A

basal lamina; reticular lamina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The basal lamina is synthesized by

A

epithelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

The reticular lamina is synthesized by

A

fibroblasts of lamina propria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

The basement membrane is best visualized with what stain?

A

PAS, since basement membrane (specifically, the reticular lamina) is rich in proteoglycans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

(T/F) The basal lamina is completely acellular.

A

True.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the further subdivisions of the basal lamina? (2)

A

lamina lucida; lamina densa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe the lamina lucida.

A

rich in laminins which bind to junctions on cell surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe the lamina densa. (4)

A

rich in type IV collagen, fibronectin, proteoglycans, and linking fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Through which structures do cells bind to the basal lamina? (2)

A

through hemidesmosomes and focal adhesions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the external lamina?

A

variant of basal lamina that covers skeletal/smooth muscle and transmits force generated by these muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Compare the reticular and basal lamina in terms of thickness.

A

reticular lamina is much thicker than the basal lamina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

(T/F) The reticular lamina is not acellular.

A

False, the reticular lamina (like the basal lamina) is acellular.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What structures do hemidesmosomes use to connect epithelial cells to the basal lamina?

A

use integrins to connect intermediate filaments (keratins, cytokeratins, tonofilaments) of epithelial cells to basal lamina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the two types of basal membrane junctions?

A

hemidesmosomes; focal adhesions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Focal adhesions use integrins to connect what structures together?

A

use integrins to connect actin filaments of epithelial cells to the basal lamina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the four types of lateral membrane junctions?

A

zonula occludens (tight junction); zonula adherens (adherens junction); desmosomes (macula adherens); gap junctions (macula communicans)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Where are tight junctions located?

A

encircles epithelial cells at the top of lateral membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Tight junctions are connected to

A

actin filaments of the terminal web

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Which junction is responsible for apical/basolateral polarity?

A

tight junctions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is the function of tight junctions?

A

provides a barrier that blocks or restricts passage of solutes between epithelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Where are adherens junctions located?

A

encircle epithelial cells just basal to zonula occludens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Adherens junctions are connected to

A

actin filaments of the terminal web

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Contrast tight and adherens junctions.

A

actin linkages are more extensive at adherens junctions than at tight junctions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is the function of adherens junctions?

A

provide most of mechanical strength necessary to seal epithelium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Where are desmosomes located? (2)

A

present in small foci that are scattered along lateral membrane; common just basal to adherens junctions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Desmosomes connect

A

intermediate filaments (cytokeratins) of adjoining cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What are the functions of desmosomes?

A

provide mechanical strength; major mechanism holding adjacent cells together in epithelia, particularly epithelia subject to abrasion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What makes up the tripartite junction?

A

tight junction + adherens junction + desmosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Where are gap junctions found?

A

present in foci along lateral membrane

40
Q

Describe the linkage function of gap junctions.

A

do NOT have any cytoskeletal linkages and do NOT provide structural strength

41
Q

What is the function of gap junctions?

A

provide contiguous portal between cells and help to coordinate actions of epithelia

42
Q

(T/F) Gap junctions play an important role in providing structural strength to cells.

A

False

43
Q

What are the four possible morphologies of the apical membrane?

A

primary cilia; motile cilia; microvilli; stereocilia

44
Q

Describe the composition of motile cilia.

A

core of microtubules (9xdoublet+2 axoneme) that inserts into basal body

45
Q

What causes cilia to beat?

A

action of dyneins on axonemal microtubules

46
Q

Motile cilia are most common on

A

pseudostratified and simple columnar epithelia

47
Q

Describe the composition of primary cilia.

A

9+0 axoneme that inserts into centriole

48
Q

Contrast motile and primary cilia.

A

primary cilia lack motile structures and are longer than motile cilia

49
Q

What is the function of primary cilia?

A

play signaling/sensing roles

50
Q

Primary cilia are found on

A

most non-dividing epithelial cells

51
Q

(T/F) A cell can have more than one primary cilium.

A

False

52
Q

Describe the composition of microvilli.

A

core of actin filaments that insert into the terminal web

53
Q

Are microvilli motile?

A

No.

54
Q

What is the function of microvilli?

A

serve to increase apical membrane surface area

55
Q

Microvilli are present on

A

most epithelial cells

56
Q

What is a brush border?

A

when highly abundant, microvilli form a “brush border”

57
Q

Describe the composition of stereocilia.

A

core of actin filaments that insert into the terminal web

58
Q

Contrast stereocilia and microvilli.

A

stereocilia are much longer than microvilli and can be branched

59
Q

Where are stereocilia found?

A

since they have specialized functions, present at only a few locations, like the testes or inner ear

60
Q

What does it mean to have a simple epithelium?

A

all cells touch the basement membrane

61
Q

What does it mean to have a stratified epithelium?

A

multiple layers but only the most basal cells touch the basement membrane

62
Q

Epithelia are classified according to

A

the shape of the most superficial layer

63
Q

What are the two types of special morphologies of cells?

A

pseudostratified epithelia; transitional epithelia

64
Q

What is the composition of pseudostratified epithelia?

A

both short cuboidal and tall columnar cells

65
Q

Describe the location of pseudostratified epithelia.

A

all cells sit on basement membrane but not all cells reach the lumen

66
Q

Where is pseudostratified epithelium prevalent?

A

in the respiratory system

67
Q

Describe the appearance of transitional epithelia.

A

appearance transitions from stratified cuboidal (relaxed state) to stratified squamous (distended state)

68
Q

Keratinization occurs in what kind of epithelium?

A

normally only occurs in stratified epithelia exposed to dry conditions or subject to abrasion (i.e. skin or tongue)

69
Q

An epithelium is termed “keratinized” when

A

the most superficial layer fills with keratins and cells lose their nuclei

70
Q

Give an example of a keratinized epithelium.

A

epidermis

71
Q

What is metaplasia?

A

conversion of epithelium into abnormal form in response to stress

72
Q

How does metaplasia differ from neoplasia or dysplasia?

A

cells in metaplastic state are NOT transformed, unlike dysplasia or neoplasia

73
Q

Describe how smoking causes metaplasia.

A

smoking causes pseudostratified epithelium of trachea and bronchi to adopt stratified squamous morphology, which provides better abrasion resistance

74
Q

Describe how acid reflux causes metaplasia.

A

acid reflux causes stratified squamous epithelium of esophagus to adopt simple columnar morphology, which has better resistance to acid because of more mucus production

75
Q

Describe how puberty causes metaplasia.

A

puberty causes simple columnar epithelium of endocervix into stratified squamous morphology similar to surrounding ectocervix and vagina

76
Q

Endothelium refers to

A

simple squamous epithelium that lines blood vessels

77
Q

Mesothelium refers to

A

simple squamous epithelium on surface of most organs and lines body cavities such as the peritoneum

78
Q

Urothelium refers to

A

transitional epithelium in urinary tract

79
Q

Explain how glands form.

A

epithelial sheet invaginates and grows into underlying connective tissue

80
Q

Define exocrine.

A

secretory products leave cell via apical surface, where they enter environment directly or via duct

81
Q

Define endocrine.

A

secretory products leave cell via basal surface, where they diffuse into bloodstream

82
Q

Define paracrine.

A

like endocrine, but products act on nearby cells rather than via bloodstream

83
Q

What are the three mechanisms of exocrine secretion?

A

merocrine; holocrine; apocrine

84
Q

Define merocrine.

A

secretory vesicles/granules fuse with plasma membrane and expel products into lumen

85
Q

Define holocrine.

A

cell fills with secretory products and then undergoes apoptosis, rupturing its plasma membrane and releasing secretory products into lumen

86
Q

Define apocrine.

A

exocrine mechanism in which cytosolic secretory products are packaged and budded off from apical surface of cell

87
Q

What are the three possible shapes of the secretory portion of the exocrine gland?

A

tubular; acinar; alveolar

88
Q

Define tubular [shape of secretory portion of exocrine gland].

A

secretory elements line a tubular lumen

89
Q

Define acinar [shape of secretory portion of exocrine gland].

A

secretory elements line a small spherical lumen (i.e. the lumen is smaller than the secretory epithelial cells)

90
Q

Define alveolar [shape of secretory portion of exocrine gland].

A

secretory elements line a large spherical lumen (i.e. lumen is wide and is usually bigger than the secretory epithelial cells)

91
Q

What are the three types of secretory content of exocrine glands?

A

serous; mixed; mucous

92
Q

Define serous [content of secretory portion of exocrine gland].

A

secretory elements secrete watery protein products

93
Q

Define mucous [content of secretory portion of exocrine gland].

A

secretory elements secrete mucin, a heavily glycosylated protein that is the principal component of mucus

94
Q

Define mixed [content of secretory portion of exocrine gland].

A

both serous and mucous secretory elements that combine in a common duct

95
Q

Differentiate between simple and compound ducts.

A

simple = single non-branching duct; compound = has a branching ductal system

Microanatomy (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions