Tissues of the human body - Epithelia Flashcards
1
Q
Describe Epithelia
A
It covers the body surfaces, lines hollow organs, tubes, cavities, and ducts as well as forms glands
2
Q
What is the primary function of the Epithelia?
A
Protection, filtration, secretion, absoption, and excretion
3
Q
True or false - epithelia lines the inside and outside of the bowels?
A
True
4
Q
What does epithelia look like?
A
It is arranged in continuous sheets as single or multiple layers
5
Q
What are the names for the different types of junctions
A
Tight junction
Adherens junction
Gap junction
Desmosomes
Hemidesmosomes
6
Q
What is your acronym for remebeing the junctions and their different types of proteins involved?
A
Today opera came Along cause chris Gave in on Doing catherines klingon Homework in lower Klingon
7
Q
What are the key functions of epithelial tissues?
A
Selective barriers that limit or aid transfer
Secrete waste onto a free surface
Protective against things like abrasions
8
Q
The apical layer is located…?
A
Inside our intestines or outside of the body - on the outer surface
9
Q
Lateral junctions include…?
A
Tight junction
Adherens junction
Gap junction
Desmosome
Hemidesmosome
10
Q
What is the basal attached to?
A
Attached to the basement membrane
11
Q
`Where are cytoskeletons located?
A
Inside of cells
12
Q
Where are microfilaments found?
A
Bundled beneath cell membrane and cytoplasm
13
Q
What is the primary function of the microfilaments?
A
Strength, alters shape, link cytoplasm to membrane, tie cells together, and muscle contraction.
14
Q
What is an example of microfilaments?
A
ACTIN - protein
15
Q
What makes up the cytoskeleton of a cell?
A
Microfilaments and intermediate filaments
16
Q
What is the primary function of the intermediate filaments?
A
Strength, move materials through cytoplasm and around cell
17
Q
What is an example of intermediate filaments?
A
Keratin
18
Q
Describe intermediate fillaments
A
They are thicker and more course in nature
19
Q
What would you say tight junctions looks like?
A
They look like they have been sewed together
20
Q
What is the primary function of the Tight Junctions
A
Provide a tight barrier so material can’t slip from lumen down beside the cells into the superstitious spaces.
It is electrically tight so that ions and other material cannot slip through
21
Q
True or false - the more strands the tighter the junction
A
True
22
Q
What are the 2 main proteins involved in tight junctions?
A
Claudins and Occludins (they act as a damming material)
23
Q
How do tight junctions keep cell polarity?
A
They do this by preventing migration of proteins between apical and basal surfaces
24
Q
What is the adherens junction also know as?
A
The belt junction
25
What are the main proteins involved in the adherens junction
Cadherin and catenins
26
What do catenins do within the adherens junction?
Catenins link the ACTIN to cadherins
27
Why do Adherens junctions have a plaque layer of proteins on the inside of the cell?
To help join ACTINS to cadherins
28
What is the main function of the adherens junction?
Prevents cell separation from tension forces, like contractions.
29
What is plaque?
Collection of proteins inside of the cell
30
True or False - the tight junction has more basal then the adherens
False
31
True or False - adherens junction the only junction with plaque
False - Desmosome junction also contains plaque
32
Where is the Desmosome junction most common?
Most common in skin epithelium and cardiac cells of the heart to prevent pulling apart
33
True or false - in the adherens junction, plaque attaches to microfilaments
True - plaque attached to the microfilament ACTIN
34
True or false - plaque in the desmosome layer attaches to microfilaments
False - plaque in adherens junction attaches to microfilaments (ACTIN). Plaque in desmosome junction attached to intermediate filaments consisting of the protein Keratin.
35
Intermediate filaments in desmosome perform what function?
They extend from plaque from one side of the desmosome to plaque on the other side, and provide stability to cells and tissue.
36
Keratin in the desmosome junction is...?
A cytoskeletal intermediate filament
37
What is the main function of the Gap junction?
They control transfer of nutrients and waste between cells, and allow cells in tissue to communicate with one another.
38
Where are Gap junctions most important and why?
Parts of the nervous system, muscles in the heart, gastrointestinal tract, and the uterus. They are important because information sharing in these spaces is crucial.
39
How many Connexin's make up a single Connexon?
6
40
How many Connexon's make up a hemichannel?
2
41
How many Hemichannels make up a Gap junction?
2
42
True or false - Gap junctions allow all molecules to pass through?
False - Gap junctions only allow ions and small molecules to diffuse through. Large molecules such as vital intercellular protein is not allowed.
43
Describe how Gap junctions form
6 connexins come together and form a connexon.
They then go out into the membrane and look for another connexon.
Once they find another connexon, they change orientation and join together.
They form a tunnel that connects neighboring cells - helps with diffusion of molecules and communication.
44
True or false - each connexin is made up of the same protein
False - each connexin is a different protein
45
Describe how proteins link in the hemidesmosome
Integrin works as the linking protein - it binds itself to laminin in the basement membrane - then to keratin intermediate filament in cytoplasm
46
What are the 2 main functions of the hemidesmosome?
Connects epithelia to basement membrane
Links cellular basal intermediate filament (keratin) to basement membrane (BM)
47
Where does the name "hemidesmosome" arise from?
Comes from the fact that they look like half a desmosome
48
True or false - cadherin is the transmembrane glycoprotein in hemidesmosome
False - it is integrin
49
True or false - cadherin is the transmembrane glycoprotein in hemidesmosome
False - integrin is the linking transmembrane glycoprotein in the hemisdesmosome
50
What comprises a "junctional complex"?
Tight junction, adherens junction, and the desmosome.
51
What are the different surfaces of the epithelial cells?
Apical, Lateral, and Basal
52
True or false - only some epithelia overlay the basement membrane.
False - ALL epithelia overlay the basement membrane
53
What are the 2 parts of the basement membrane?
Basal lamina and Reticular lamina
54
What does the basal lamina contain?
Contains collagen, laminin, other proteoglycans, glycoproteins, etc.
55
What secretes basal lamina?
Epithelial cells
56
What does reticular lamina contain?
Contains fibrous proteins such as fibronectin, collagen, etc.
57
What is the reticular lamina produced by?
Produced by cells of the underlying connective tissue known as fibroblasts.
58
Where does the apical layer of the epithelia face?
Apical (free) surfaces face the bodies surface, a body cavity, the lumen (interior space) of an internal organ, or a tubular duct that receives cell secretions
59
True or false - Apical layers may sometimes contain cilia or micovilli
True
60
What do the lateral surfaces of the epithelia face?
They face the adjacent cells on either side.
61
What can the lateral surfaces of epithelia contain?
They can contain:
Tight junctions, adherens junctions, desmosomes, and/or gap junctions
62
True or false - the basal surface is opposite the apical surface in the epithelia cells?
True
63
Describe the relationship between the basal layer, the basement membrane, and the hemidesmosome
The basal surface adheres to the deepest layer of epithelial cells such as the basement membrane. Hemidesmosomes in the basal surfaces of the deepest layer of epithelial cells anchor the epithelium to the basement membrane.
64
True or false - epithelia contain blood vessels but not nerves
False - epithelia contain nerves not blood vessels
65
What does epithelia combine with to form special sense organs?
Combines with nervous tissue to make special sense organs for smell, hearing, vision, and touch.
66
What are the 2 types of epithelia tissue?
Covering and lining
Glandular epithelium
67
What are the functions of the basement membrane
Supports the overlying epithelium
68
True or false - Once malignant melanoma penetrates the basement membrane and goes into the surface, there is a lower risk of melanoma/sickness spreading.
False - once penetrated there is a higher risk of metastasis (spread)
69
What are the ABCD's of melanoma
Asymmetry: One half of a mole doesn't match the other
Border irregularity: edges are ragged, notched, or blurred
70
What are the ABCD's of melanoma
Asymmetry: One half of a mole doesn't match the other
Border irregularity: edges are ragged, notched, or blurred
Color: Mix of brown, black, red, white, or blue.
Diameter: Greater then 6mm
71
How is covering and lining epithelia classified?
2 categories: a.) the arrangement of cells in layers and b.) the shapes of the cells
72
What are the 3 different arrangements for covering and lining epithelia?
Simple, stratified, and pseudostratified
73
Describe "Simple" arrangement of epithelia and its functions
Single layered: Used in secretion, absorption, osmosis, and filtration
74
Describe "Stratified" arrangement of epithelia and its functions
Two or more layers: Acts as a protective barrier for underlying tissue in places where there is significant wear and tear
75
Describe "pseudostratified" arrangement of epithelia and its functions
Appears to have multiple layers of cells because the nuclei lie at different levels and not all cells reach the apical surface.
However - all cells reach the BM and are therefore ACTUALLY simple epithelium
76
What are the 3 different shapes of epithelia cells
Squamous
Cuboidal
Columnar
Transitional
77
Describe squamous shape in epithelia as well as its function
Flat and thin - helps allow passage via diffusion
78
Describe Cuboidal shape in epithelia as well as its function
About as tall as they are wide (square) - may have microvilli at apical surface and assists with secretion and absorption
79
Describe columnar shape in epithelia cells and their function
More tall then wide (columns) - assit with secretion and absorption and assist with protection of underlying tissues.
-Their apical surfaces may have microvilli or cilia
80
Describe transitional shape in epithelia cells and their function
A stratified epithelium in which cells can change shape from cuboidal to flat and back depending on the organ shap
81
Describe transitional shape in epithelia cells and their function
A stratified epithelium in which cells can change shape from cuboidal to flat and back depending on organ shape
82
Where are transitional epithelium found?
Only in the urinary bladder which needs to change shape constantly to allow for urination
83
What are microvilli and what is their function
They are cellular membrane protrusions that increase the surface area for diffusion and minimize any increase in volume
83
What are microvilli and what is their function
They are cellular membrane protrusions that increase the surface area for diffusion and minimize any increase in volume
84
Name the 3 types of Simple epithelia
Simple squamous
Simple cuboidal
Simple columnar
85
Name the 4 types of stratified epithelia
Stratified squamous (keratinized and non-keratinized)
Stratified cuboidal
Stratified columnar
Transitional
86
Name the different types of pseudostratfied epithelia
Pseudostratified columnar is the only one (ciliated or non - ciliated)
87
Describe the features of simple squamous epithelium
Most delicate epithelium
Where their is filtration (kidneys) and diffusion (lungs); and secretion - it is where lubrication or slippery surfaces are needed
88
What is the appearance of simple squamous epithelium
Thin, flat, and somewhat irregular like a jigsaw. Look similar to fried eggs or paving stones.
89
What are some specialized subtypes of simple squamous epithelium
Mesothelium: lines the pericardial, pleural, and peritoneal cavities (eg heart for pericardium, plural space around lungs, etc)
Endothelium: Lines inside of heart and blood lymphatic vessels
90
Where are simple squamous epithelium located?
In Bowmans capsule in the kidney
Lines the cardiovascular and Lymphatic Systems
Inside of the eye
Alveoli of lungs
Visceral cavity linings
Inside blood vessels
Inside heart
91
Where is simple squamous epitheliam NOT found
In body areas subject to mechanical stress or wear and tear
92
Where is simple squamous epithelia NOT found
In body areas subject to mechanical stress or wear and tear
93
What is the function of a serous membrane and how does it perform this function
To reduce friction within the body. It does this by lining organs and body cavities with a layer of slick, lubricated cells
94
Describe the function of simple cuboidal epithelium
Provides secretion and absorption
95
Describe the appearance of simple cuboidal epithelium
Cuboidal or hexagonal boxes
96
What are the specialised subtypes of simple cuboidal epithelium
There are none
97
`Where is simple cuboidal epithelium located
Pancreas ducts
Parts of kidney tubules
Smaller ducts of many glands
Secretory chambers of thyroid
Anterior surface of lens
Pigmented epithelium at posterior retina
Secretory part of some glands like thyrroid
98
What are cilia, what is there function and where are the located.
Like seaweed in the sea.
Take material and move it along in places like the lungs and fallopian tubes
99
Describe the features of Simple Columnar Epithelium
Has more cytoplasm so more organelles
Is a bigger cell therefore more metabolically active
More cytoplasm
100
Describe the features of Simple Columnar Epithelium
Has more cytoplasm so more organelles
Is a bigger cell therefore more metabolically active
More cytoplasm
101
Describe the 2 major subtypes of Simple columnar epithelium
Non ciliated and ciliated
102
Describe the appearance of Simple columnar epithelium
Rectangular
Often hexagonal but taller and more slender than cuboidal
Nuclei often elongated and near the base of the cell
Height of cell is several times the distance between adjacent nuclei
103
True or false - Simple columnar epithelium can have cilia OR microvilli
True
104
What is a goblet cell?
A goblet cell is a modified columnar cell that secretes mucus at the apical surface to aid with lubrication
105
Describe the features of Non-ciliated simple columnar epithelium
Single layer
Micorvilli on apical surface
Have goblet cells interspersed
106
What does "non-motile" mean?
Not capable of movement
107
Describe the function of microvilli in non-ciliated simple columnar epithelium
Non-motile cytoplasmic projections
Increase surface area of plasma membrane thus increasing rate of absorption
108
Where are non-ciliated simple columnar epithelium found?
In places in need of secretion and absoprtion - eg linings of the digestive, respiratory, and reproductive tracts and most of the urinary tract.
109
Describe the features of ciliated simple columnar epithelium
Single layers
Have goblet cells as well
110
Describe the appearance of microvilli
Finger-like appearance
111
Describe the function of cilia within ciliated simple columnar epithelium
Cilia beat in unison, moving mucus and foreign particles towards throat where they can be coughed up and swallowed or spit out.
112
What can speed up the movement of mucus or foreign particles into the throat to be ejected?
Sneezing or coughing
113
How does ciliated simple columnar epithelium help within the ovaries
Cilia on the epithelium help move oocytes expelled from ovaries through uterine (fallopian) tubes into the uterus
114
Where is Stratified Squamous epithelium mostly located
Located where mechanical or chemical stresses are severe (lining of mouth, esophagus, etc)
115
What is a microbe?
A bacteria that can cause disease or fermentation
116
Why are Stratified squamous epithelium sometimes packed with keratin?
In some places where mechanical stress and dehydration is a major issue, apical cells are packed with keratin which makes the surface tough and waterproof (skin)
117
Describe the appearance of simple stratified epithelium
Cells form layers like plywood or pancakes in upper layers
Lower layers may be cuboidal or columnar
Cells furthest from nutrition are thinner and less active
118
What are the 2 specialized subtypes of Stratified squamous epithelia
Keratinized and non-keratinized
119
Where is keratinized stratified squamous epithelia found?
Skin
120
Where is non-keratinized squamous epithelia found?
Mouth, throat, tongue, esophagus, anus, and vagina
121
Why do places like the mouth, throat etc not contain keratinized stratified squamous epithelium
Keratinized version is only found on skin as it works to protect against abrasion and UV light and then sheds. You do not want dead skin shedding in your mouth.
122
True or false - it is the appearance of the innermost cells in epithelium that determine their name.
False - it is the appearance of the outermost cells that determine whether it is squamous/cuboidal/columnar
123
Describe the function of Keratinized stratified squamous epithelium
Keratinized protects against abrasion, water loss, UV light, and foreign invasion. As keratinized cells push towards surface, they become thinner and less active. They dry up and eventually peal of the apical layer as dead skin.
124
True or false - only non keratinized stratified squamous epithelium protects against abrasion, water loss, UV light, and microbes.
False - both keratinized and Non-keratinized protect against these things. Both are the first line of defense against microbes.
125
Describe the features of pseudo-stratified columnar epithelium
All cells reach the BM but not all reach the apical surface of the tissue
It is actually a simple epithelium (thus the pseudo=fake)
126
Describe the appearance of the pseudostratified columnar epithelium
Nuclei at all different levels
Appears to have several layers but it is not actually the case
127
Name the 2 specialized subtypes of Pseudostratified columnar epithelium
Pseudostratified CILIATED columnar epithelium
AND
Pseudostratified NON-CILIATED columnar epithelium
128
Describe the features of pseudostratified ciliated columnar epithelium
Cilia on some cells
Secrete mucus from goblet cells
129
Describe the features of pseudostratified non-ciliated columnar epithelium
No cilia and no goblet cells
130
Where are non-ciliated pseudostratified columnar epithelium found and what is there function?
Lines larger ducts of many glands, epididymis, and parts of the male urethra.
Their function is absorption and protection.
131
Where are Ciliated pseudostratified columnar epithelium found and what is their function?
Most of the upper airways. Function: secretes mucus that traps foreign particles and cilia sweep away mucus for elimination from body
132
True or false - stratified cuboidal epithelium is rare
True
133
Describe the appearance of stratified cuboidal epithelium
Two or more layers of cells and are cube shaped in the apical layer
134
Where are stratified cuboidal epithelium found?
Ducts of adult sweat glands and esophageal glands as well as the male urethra
135
What is the function of stratified cuboidal epithelium?
Protection; they also provide a limited amount of secretion and absorption
136
Describe the appearance of stratified columnar epithelium
Basal layer usually consist of shortened, irregular shaped cells. Shaped like columns
137
True or false - stratified columnar epithelium are common
False - they are uncommon and only found in the apical layer
138
Where are stratified columnar epithelium found?
Lines part of urethra, large excretory duct of some glands (esophageal gland), small areas in anal mucous membrane, part of conjunctiva in eye
139
What is the function of Stratified columnar epithelium
Protection and secretion
140
Describe the appearance of transitional epithelium
Varies: in relaxed or unstretched state it looks like stratified cuboidal epithelium except that the apical layers tend to be large and rounded.
As it is stretched, cells become flatter and look like stratified squamous epithelium.
141
Where is transitional epithelium found?
Lines the urinary bladder and portions or urethra and ureters.
142
Why is transitional epithelium important within the bladder?
Allows urinary organs to stretch and maintain protective lining while holding variable amounts of fluid without rupturing.
Multiple layers make and elasticity make it ideal for hollow lining structure subject to expansion.
143
Define glandular epithelia
They are glands that consist of a single cell or a group of cells that secrete substances into ducts, onto a surface or into blood.
144
How are glandular epithelia classified?
They are classified according to where they secrete their substances
145
True or false - the function of all glandular epithelia is secretion
True
146
Describe the secretion pathway of the endocrine gland
Secretes directly into blood usually via traversing interstitial fluid
147
Describe the secretion pathway of the exocrine gland
Secretes into ducts that empty onto the surface of a covering or lining epithelium
148
Give example of an endocrine gland
Pituitary, pineal, thyroid, parathyroid - effect things over a distance
149
Give an example of an exocrine gland
Sweat and salivary glands, oil glands, wax glands, pancreas - generally effects things locally
150
How do endocrine glands excrete fluid?
Usually through diffusion directly into the bloodstream
151
How do exocrine glands secrete fluid?
Directly onto the surface eg sweat gland and skin
152
What is a single cell gland
They are Epithelia that have independent, scattered gland cells. Individual secretory cells are called mucous cells and they secrete mucin. The apical cytoplasm is filled with large secretory vesicles that look clear or foamy in a light micrograph.
153
What is an example of a single cell exocrine gland?
Goblet cell
154
Name the 8 different types of multicellular exocrine glands
Simple tubular
Simple branched tubular
Simple coiled tubular
Simple branched acinar (alveolar)
Compound tubular
Compound acinar (alveolar)
Compound Tubuloacinar
155
What are the 3 characteristics used to describe structure of multicellular glands
Structure of duct
Structure of secretory duct
Relationship between the two
156
When is an exocrine gland called "simple"?
A gland is simple if it has a single duct that does not divide on its way to the gland cells
157
What is an example of a simple tubular gland?
Intestinal glands
158
What is an example of simpled coiled tubular?
Merocrine sweat glands
159
What is an example of a simple branched tubular?
Gastric glands
Mucous glands of esophagus, tongue, duodenum
160
What is the difference between simple alveolar (acinar) and simple tubular?
Simple alveolar (acinar) form sack-like pockets at the ends
161
What is an example of a simple branched alveolar?
Sebaceous (oil) glands
162
When is an exocrine gland "compound"?
A gland is compound if the duct divides one or more times on it's way to the gland ells
163
What is an example of a compound tubular gland?
Mucous glands in mouth
164
What is an example of compound alveolar (acinar)
Mammary glands
