Epithelium Flashcards
1
Q
What does all epithelium rest on?
A
basement membrane
2
Q
The epithelium forms the ______ of exocrine and endocrine glands.
A
parenchyma (secretory portion)
3
Q
Characterisitcs of Epithelium:
A
- Lines all surfaces (external and internal)
- Structural Polarity
- Avascular (Nutrients delivered by diffusion)
- Highly cellular
- Little intercellular space and closely apposed to one another by cell junctions.
- High regenerative capacity
4
Q
6 functions of the epithelium:
A
PASSRT
- protection
- absorption, secretion, excretion
- selective permeability barrier
- sensory reception
- reproduction
- transport of material via cilia
5
Q
Simple epithelium:
A
one cell layer thick
- can be:
- simple squamous (flat)
- simple cuboidal
- simple columnar
6
Q
Stratified Epithelium:
A
two or more cell layers thick
- can be:
- stratified squamous (flat)
- stratified cuboidal
- stratified columnar
7
Q
Transitional Epithelium:
A
- Stratified in appearance; however, surface cells can be dome shaped or flat.
Nuclei are rounded in appearance.
8
Q
Pseudostratified Columnar Epithelium:
A
- All cells rest on the basement membrane but not all cells reach the luminal surface.
Cell surface modifications are ALWAYS present: cilia, steriocilia.
9
Q
Basement Membrane/Basal lamina
A
- Supports the tissue and forms the boundary between epithelium and connective tissue
10
Q
What are the arrow pointing to?
A
- blue = cell
- purple = connective tissue
- black = basement membrane
11
Q
All blood vessels are lined with:
A
simple squamous epithelium
12
Q
Functions of simple squamous epithelium:
A
- fluid transport
- gaseous exchange
- lubrication
- reducing friction (viscera)
13
Q
Some notable locations of simple squamous epithelium:
A
- loop of henle
- parietal layer of Bowman’s capsule
- pulmonary alveoli
- lining of ventricles and atria
14
Q
What is the arrow pointing to?
A
simple squamous epithelium of the spleen
(mesothelium)
15
Q
Distinguishing characteristic of simple squamous epithelium:
A
- one cell layer thick
- flat cells
- flat nuclei
16
Q
What is the black arrow on the right pointing to?
A
simple squamous epithelium
bowman’s capsule renal corpuscle
17
Q
Distinguishing characteristics of simple cuboidal epithelium:
A
- one cell layer thick
- cube-shaped cells
- nuclei round and usually in center of cell
18
Q
Functions of simple cuboidal epithelium:
A
- absorption
- secretion
- protection
19
Q
Notable locations of simple cuboidal epithelium:
A
- lining of ducts in glands
- covering of ovaries
- kidney tubules
20
Q
What is the arrow pointing to?
A
simple cuboidal epithelium
(lining of kidney collecting duct)
21
Q
Distinguishing characteristics of simple columnar epithelium:
A
- one cell layer
- rectangular shaped cell
- round to oval nuclei
MAY have surface modifications
22
Q
Functions of simple columnar epithelium:
A
- absorption
- secretion
- protection
- transportation
23
Q
Notable locations of simple columnar epithelium:
A
- nasal sinuses
- oviducts
- uterus
- digestive tract
- gall bladder
24
Q
What cells are these?
A
simple columnar epithelium
25
What is the black arrow on the right pointing to?
junctional complex
26
What is the black arrow in the center pointing to?
simple columnar epithelium cell
microvilli brush border present
goblet cells present
27
What is the black arrow pointing to?
goblet cell
28
What kind of cell is this EM of?
goblet cell
29
What is the red arrow pointing to?
Simple Columnar epithelium with cilia
| (oviduct)
30
What is this a cross-section of?
cilia
(cilia made of microtubules; protein = tubulin)
31
Stratified epithelium is identified by what cell layer?
the cell layer closest to the lumen
32
Distinguishing characteristics of stratified epithelium:
* two or more cell layers thick
* NEVER cilia or stereocilia on cell surface
33
Function of stratified epithelium:
* absorption
* secretion
* protection
34
Distinguishing characteristics of stratified squamous epithelium:
* Cell layer closest to lumen is always nucleated
* Nuclei are flattened in appearance
35
Functions of stratified squamous epithelium:
* protection
* prevents dehydration
36
Notable locations of stratified squamous epithelium:
* vagina
* anal canal
* mouth
* vocal cords
* epidermis (keratinized)
37
What cells are the top cell layer?
stratified squamous epithelium
| (palentine tonsil)
38
What is the hot pink layer on top in this image?
Keratinized Stratified Squamous Epithelium
(Cell layer closest to lumen lack nuclei)
39
Distinguishing features of stratified cuboidal epithelium:
* 2 cell layers thick
* cells are cuboidal
40
Functions of stratified cuboidal epithelium:
* absorption
* secretion
* protection
41
Notable locations of stratified cuboidal epithelium:
lines ducts of sweat glands
42
What kind of cell is circled?
stratified cuboidal epithelium
| (layer closest to lumen is cuboidal)
43
Distinguishing features of stratified columnar epithelium:
* 2 cell layers thick
* cells are columnar
44
Functions of stratified columnar epithelium:
* secretion
* protection
45
Notable locations of stratified columnar epithelium:
* mammary glands
* salivary glands
* male urethra
* conjunctiva of eye
46
What cell is boxed in blue?
stratified columnar epithelium
47
What kind of cells are outlined in red?
stratified columnar epithelium
## Footnote
**with goblet cells**
48
Distinguishing features of pseudostratified epithelium:
* All cells touch basement membrane
* Not all cells touch the luminal surface
* Nuclei in all different planes of section
* Apical area devoid of nuclei
* Always has a surface modification: Cilia or Stereocilia
49
Pseudostratified epithelium always has:
cilia or sterocilia
50
Functions of pseudostratifed epithelium:
* Secretion
* Absorption
* Lubrication
* Protection
* Transportation via cilia
51
What cells are pictured here?
pseudostratified epithelium with cilia
## Footnote
**with goblet cells**
52
What cells are pictured here?
pseudostratified epithelium with sterocilia
53
What cell surface modification is pictured?
microvilli
| (brush border)
54
What cell surface modification is pictured?
cilia
| (airy; made of microtubules)
55
What cell surface modification is pictured?
stereocilia
56
Distinguishing features of transitional epithelium:
* Stratified
* Top layer of cells is dome shaped
* Top layer of cells can be flat
* **_Nuclei are rounded_** whether top layer of cells are domed or flat
* Occasional binucleated cells
57
Location of transitional epithelium:
lines urinary tract
58
What epithelium is pictured here?
transitional epithelium
| (empty bladder)
59
What type of epithelium is pictured here?
transitional epithelium (nuclei still rounded)
(full bladder)
60
What are the black arrows pointing to?
* unit membrane in the bladder
* invaginations of the plasma membrane in the bladder that allow the bladder to expand when/if it becomes full
61
What type of epithelium is pictured?
stratified squamous epithelium
62
What type of epithelium is pictured?
transitional epithelium
63
What are the arrows/circle outlining?
junctional complex/terminal bar
64
Function of Zonula Occludens (Tight Junction):
* Maintains selective passage of substances from one side of the epithelium to the other.
65
What is the red arrow pointing to?
zona occludens (tight junction)
66
What are the red arrows pointing to?
zona occludens (tight junction)
67
Function of zonula adherens (belt desmosome):
Belt-like attachment that anchors cell to cell
68
What is the red arrow pointing to?
zonula adherens (belt desmosome)
69
Key molecules in the zonula occludens:
Occludin and claudins
| (tight junction)
70
Key molecules in the zonula adherens:
actin, cadherins, and catenins
| (belt desmosome)
71
Key molecules in macula adherens:
intermediate filaments, desmoplakin, desmoglein
72
What are the black arrows pointing to?
macula adherens
(spot desmosomes)
ladder-like appearance
73
What is this an image of?
zonula adherins
| (belt desmosome)
74
What is this an image of?
zonula occludens
| (tight junction)
75
What is this an image of?
macula adherens
| (spot desmosome)
76
What is this an image of?
hemidesmosome
77
Hemidesmosome function:
cell to matrix attachment
78
What is this an image of?
gap junction between two muscle cells
| (connexins)
79
What kind of glands are pictured?
exocrine glands
(secrete products into ducts to the surface)
80
What kind of glands are pictured?
endocrine glands
(secretes products directly into blood stream via capillaries and lymphatic vessels)
