Epithelium Flashcards
1
Q
general features of epithelia
A
linked tightly together by intracellular junctions, found in the lining of all cavities and surfaces
2
Q
major function of epithelia
A
barriers between two compartments
3
Q
epithelium
A
free apical surface, and basal surface that rests on a non-living layer of ECM (basement membrane)
4
Q
basement membrane
A
non living layer ECM, consists of true lamina (secreted by epi cells) and reticular lamina (secreted by conn. tissue cells)
5
Q
classification of epithelia
A
simple, stratified, pseudostratified // squamous, cuboidal, columnar
6
Q
simple epithelia
A
one layer of cells, all cells touch both free apical surface and basal surface touching basement membrane
7
Q
stratified epithelia
A
more than one layer of cells, In a stratified epithelium, the apical or superficial layer of cells faces the free surface and is separated from the basal lamina by one or more layers of cells.
8
Q
pseudostratified epithelia
A
all cells rest on the basal lamina, but only some have a free surface. arrangement of the nuclei is distinctive.
9
Q
squamous features
A
wide, flat, nuclei bulging out of apical surface
10
Q
cuboidal
A
cube-shaped. nucleus is round, and in the centre of the cell. cells that are wider than tall = low cuboidal
11
Q
columnar
A
taller than wide. nucleus is elongated, and on the basal side
12
Q
modifications
A
apical surface usually has modifications - microvilli, cilia, and stereocilia
13
Q
parenchyma
A
secretory section of glandular tissue
14
Q
types of tissues
A
epithelia, connective, nerve, muscle
15
Q
places you find epithlia
A
sheets of cells lining cavities and open spaces.
16
Q
functions of epithelium
A
barrier, protection, absorption, secretion, transport
17
Q
how does epithelia protect?
A
abrasion resistance - layers of dead cells (skin), mucous secreting cells; line outside of digestive organs and protect as they all slosh and bump into each other
18
Q
what does epi do to increase absorption + secretion?
A
fold a lot to increase SA
19
Q
how much blood vessel content?
A
no blood vessels
20
Q
types of apical specializations?
A
microvilli, cilia, stereocilia
21
Q
microvili features
A
cylindrical projections; 0.5-1.0 microns, increase surface area for absorption, create a “brush border” pattern, seen in digestive tract and kidney, <50% size of nucleus
22
Q
microvili structure
A
actin, hollow inside, cannot actively move, core joins actin cytoskeleton, cannot usually see individual microvili
23
Q
stereocilia features
A
modified microvilli, very long (75% cell), sparse and ragged looking, found in inner ear and male reproductive system
24
Q
cilia features
A
10x bigger microvilli, pinched appearance (beer bottle), sweeping motion moves material, found in respiratory and female reproductive (egg and uterus), has dark line beneath it (basal body)
25
cilia structure
microtubule skeleton (axenome), 9+2 arrangement of microtububles, anchor in cell = basal body = most important feature is dark line at the apical surface
26
epithelia are tightly packed. what holds them together?
cell junctions: tight junctions, adherens junctions, gap junction, and desmosomes IN THAT ORDER.
27
tight junction features
membranes are closely opposed, most apical of all the junctions, prevent movements between cells, chicken-wire/fishnet feature, occluding junction (no liquid can pass through)
28
adherens junction features
apical lateral cell junctions (just below tight junction), encircle cell completely, long parallel densities (space), NOT occluding aka liquid will get past them, consist primarily of cadherins
29
desmosome features
strong and lateral adhesion, static and structural, PROMINENT KERATIN FILAMENT WEB, parallel densities, usually straight, same cadherin famile as adherence junction, not concractile
30
gap junction features
tightly opposed membranes, generally below adherens junctions, collection of pores (connexons), regulates cell to cell communication through free movement of small molecules between cells
31
terminal bars features
all cell adhesion sites, artifact of fixation = vertical line with tiny little bulges
32
types of basal specialization
basement membrane, cell substrate adhesion
33
role of basement membrane
separates epithelium from connective tissue
34
basement membrane layers
basal lamina of epithelial origin (laminins), reticular lamina of connective tissue origin (often see collagen fibrils)
35
where find simple squamous? what surface modifications would you find?
lining all cavities, and all blood vessels, found where exchange occurs; no surface modifications
36
what is mesothelium
lines all organs; simple squamous
37
what is endothelium
lines all blood vessels; simple squamous
38
where find simple cuboidal? what are its functions? what surface modifications would you find?
lining tubes and glands; secretory and absorpative; mv/c/sc
39
where find simple columnar? what surface modifications would you find?
lines tubes (kidney, gallblader); apical modifications (mc/c/sc)
40
where would you find ciliated simple columnar cells?
oviduct only; no goblet cells present
41
where would you find simple columnar cells with microvili?
digestive tract - goblet cells are present here
42
where would you find pseudostratified columnar cells? what surface modifications would you see?
respiratory tract - will be ciliated; male reproductive tract - will be stereociliated
43
what layer should you look to in identifying which epithelium it is?
apical
44
where would you find stratified squamous epithelium?
moist areas: nose, mouth, reproductive tract; where skin meets interior
45
what distinct feature does keratonized stratified squamous epithelium have?
no nuclei
46
where would you find transitional epithelium? why?
bladder - transition is very stretchy
47
what features does transitional epithelium have?
pillow-like apical cells; these are flat when stretched (full) bladder
48
what are the different glands? contrast them
exocrine and endocrine; exocrine secretes to free surface + is connected to surface + can form ducts; endocrine secretes to circulatory system + is not connected to surface + cannot form ducts + always round
49
what are the different types of exocrine glands? define them.
merocrine/eccrine (secretes directly), apocrine (vesicle), and holocrine (whole cell)
50
what is a goblet cell? what does it do?
unicellular exocrine gland; secretes mucous in the digestive and respiratory system
51
what is a duct?
multicellular exocrine gland; it's a specialised secretory unit
52
which types of glands do you find in pancreas?
both exocrine and endocrine; the exocrine are secreting digestive enzymes and are arranged into ducts, while the endocrine are secreting insulin and arranged into cords
53
why is epithelia so prone to cancer?
highly mitotic
54
adenocarcinoma?
glandular cancer, excessive glandular tissue
55
skin carcinoma?
common and metastatic, treated by excision
56
are moles carcinoma?
no, they are a proliferation of melanocytes, and do increase susceptibility to cancer
57
what do different burn degrees mean?
1st = surface epi 2nd = penetrates epi 3rd = penetrates connective tissue
58
linked tightly together by intracellular junctions, found in the lining of all cavities and surfaces
general features of epithelia
59
barriers between two compartments
major function of epithelia
60
free apical surface, and basal surface that rests on a non-living layer of ECM (basement membrane)
epithelium
61
non living layer ECM, consists of true lamina (secreted by epi cells) and reticular lamina (secreted by conn. tissue cells)
basement membrane
62
simple, stratified, pseudostratified // squamous, cuboidal, columnar
classification of epithelia
63
one layer of cells, all cells touch both free apical surface and basal surface touching basement membrane
simple epithelia
64
more than one layer of cells, In a stratified epithelium, the apical or superficial layer of cells faces the free surface and is separated from the basal lamina by one or more layers of cells.
stratified epithelia
65
all cells rest on the basal lamina, but only some have a free surface. arrangement of the nuclei is distinctive.
pseudostratified epithelia
66
wide, flat, nuclei bulging out of apical surface
squamous features
67
cube-shaped. nucleus is round, and in the centre of the cell. cells that are wider than tall = low cuboidal
cuboidal
68
taller than wide. nucleus is elongated, and on the basal side
columnar
69
apical surface usually has modifications - microvilli, cilia, and stereocilia
modifications
70
secretory section of glandular tissue
parenchyma
71
epithelia, connective, nerve, muscle
types of tissues
72
sheets of cells lining cavities and open spaces.
places you find epithlia
73
barrier, protection, absorption, secretion, transport
functions of epithelium
74
abrasion resistance - layers of dead cells (skin), mucous secreting cells; line outside of digestive organs and protect as they all slosh and bump into each other
how does epithelia protect?
75
fold a lot to increase SA
what does epi do to increase absorption + secretion?
76
no blood vessels
how much blood vessel content?
77
microvilli, cilia, stereocilia
types of apical specializations?
78
cylindrical projections; 0.5-1.0 microns, increase surface area for absorption, create a "brush border" pattern, seen in digestive tract and kidney, \<50% size of nucleus
microvili features
79
actin, hollow inside, cannot actively move, core joins actin cytoskeleton, cannot usually see individual microvili
microvili structure
80
modified microvilli, very long (75% cell), sparse and ragged looking, found in inner ear and male reproductive system
stereocilia features
81
10x bigger microvilli, pinched appearance (beer bottle), sweeping motion moves material, found in respiratory and female reproductive (egg and uterus), has dark line beneath it (basal body)
cilia features
82
microtubule skeleton (axenome), 9+2 arrangement of microtububles, anchor in cell = basal body = most important feature is dark line at the apical surface
cilia structure
83
cell junctions: tight junctions, adherens junctions, gap junction, and desmosomes IN THAT ORDER.
epithelia are tightly packed. what holds them together?
84
membranes are closely opposed, most apical of all the junctions, prevent movements between cells, chicken-wire/fishnet feature, occluding junction (no liquid can pass through)
tight junction features
85
apical lateral cell junctions (just below tight junction), encircle cell completely, long parallel densities (space), NOT occluding aka liquid will get past them, consist primarily of cadherins
adherens junction features
86
strong and lateral adhesion, static and structural, PROMINENT KERATIN FILAMENT WEB, parallel densities, usually straight, same cadherin famile as adherence junction, not concractile
desmosome features
87
tightly opposed membranes, generally below adherens junctions, collection of pores (connexons), regulates cell to cell communication through free movement of small molecules between cells
gap junction features
88
all cell adhesion sites, artifact of fixation = vertical line with tiny little bulges
terminal bars features
89
basement membrane, cell substrate adhesion
types of basal specialization
90
separates epithelium from connective tissue
role of basement membrane
91
basal lamina of epithelial origin (laminins), reticular lamina of connective tissue origin (often see collagen fibrils)
basement membrane layers
92
lining all cavities, and all blood vessels, found where exchange occurs; no surface modifications
where find simple squamous? what surface modifications would you find?
93
lines all organs; simple squamous
what is mesothelium
94
lines all blood vessels; simple squamous
what is endothelium
95
lining tubes and glands; secretory and absorpative; mv/c/sc
where find simple cuboidal? what are its functions? what surface modifications would you find?
96
lines tubes (kidney, gallblader); apical modifications (mc/c/sc)
where find simple columnar? what surface modifications would you find?
97
oviduct only; no goblet cells present
where would you find ciliated simple columnar cells?
98
digestive tract - goblet cells are present here
where would you find simple columnar cells with microvili?
99
respiratory tract - will be ciliated; male reproductive tract - will be stereociliated
where would you find pseudostratified columnar cells? what surface modifications would you see?
100
apical
what layer should you look to in identifying which epithelium it is?
101
moist areas: nose, mouth, reproductive tract; where skin meets interior
where would you find stratified squamous epithelium?
102
no nuclei
what distinct feature does keratonized stratified squamous epithelium have?
103
bladder - transition is very stretchy
where would you find transitional epithelium? why?
104
pillow-like apical cells; these are flat when stretched (full) bladder
what features does transitional epithelium have?
105
exocrine and endocrine; exocrine secretes to free surface + is connected to surface + can form ducts; endocrine secretes to circulatory system + is not connected to surface + cannot form ducts + always round
what are the different glands? contrast them
106
merocrine/eccrine (secretes directly), apocrine (vesicle), and holocrine (whole cell)
what are the different types of exocrine glands? define them.
107
unicellular exocrine gland; secretes mucous in the digestive and respiratory system
what is a goblet cell? what does it do?
108
multicellular exocrine gland; it's a specialised secretory unit
what is a duct?
109
both exocrine and endocrine; the exocrine are secreting digestive enzymes and are arranged into ducts, while the endocrine are secreting insulin and arranged into cords
which types of glands do you find in pancreas?
110
highly mitotic
why is epithelia so prone to cancer?
111
glandular cancer, excessive glandular tissue
adenocarcinoma?
112
common and metastatic, treated by excision
skin carcinoma?
113
no, they are a proliferation of melanocytes, and do increase susceptibility to cancer
are moles carcinoma?
114
1st = surface epi 2nd = penetrates epi 3rd = penetrates connective tissue
what do different burn degrees mean?
