Epithelial Tissue Flashcards
1
Q
What is the common characteristic that categorizes tissues as “epithelial?”
A
Morphology
2
Q
What is a tissue:
- Aggregate of cells that are characterized by large amounts of intercellular materials?
- Aggreate of cells taht are characterized by small amounts of intercellular material?
- Collection of cells and cell product having one or more common function
A
3 - Collection of cells and cell product having one or more common function
3
Q
The [] line both the xternal and intrnal surfaces, of the body, developmentally and it invades the connective tissue to form the functional tissue of glands
A
Epithelium
4
Q
Epithelium is highly:
- Vascular
- Cellular
- anaerobic
- Partitioned
A
Cellular
5
Q
These are the most important epithelial functions:
A
- Protection
- Secretion
- Absorption
- Transport
6
Q
What type of “lower” membrane are all epithelia associated with?
A
Basement Membrane
7
Q
What are three examples of epithelial surface modifications?
A
Cilia
Stereocilia
Microvilli
8
Q
How does blood nourish the epithelia?
A
- FALSE - it doesnt
- Epithelial is avascular
- It receives its nourishment by diffusion from the connective tissue.
9
Q
Epithelial Cells must very diverse and resilient because they face many harsh climates on the body including:
- Skin - ?
- Lining Body Cavities - ?
- Secretory and Excretory - ?
- Lining Distensitble Organs - ?
A
- Skin - have to protect against dissecation, mechanical abrasion, bacterial infection, and radiation
- Lining Body Cavities - has to stay moist, absorb and secrete stt
- Secretory and Excretory - forms glandular tissue
- Lining Distensitble Organs - has to be able to change shape to accomdate the swelling and shrinking of things like the bladder
10
Q
What are the common characteristics of Epithelia?
A
- Highly Cellular
- Tightly Adherent
- Avascular
- High regenerative capacity
- highly polarized
- presence of basement membrane
- nuclei mirror cell shape
- derived from all 3 germ layers
11
Q
Which of the following is not a function of epithelia?
- Protection
- Transportation
- Secretion
- Action Potentials
- Lubrication
A
Action Potentials!
12
Q
Which of the following is not a function of Epithelia?
- Absorption
- Sensory Reception
- Reproduction
- Initiating Apoptosis
A
Initiating Apoptosis
13
Q
What is the difference between excretion and secretion?
A
- Excretion is getting rid of waste type products
- Secretion is an intentional release of a substance
14
Q
Why is it important for epithelia to regenerate so rapidly?
A
These cells occupy some harsh environments - ex: skin, lining of the GI tract, lining of esophagus…they get degraded quickly. So, they need to be able to reproduce/regenerate
15
Q
What are the 3 shapes and epithelial tissue can take?
A
Squamos
Cuboidal
Columnar
16
Q
How are epithelial cells named regarding their “layers?”
A
- Simple - 1 layer
- Pseudostratified - all cells are attach to a basement membrane, and not all can reach the free surface
- Stratified - 2 or more layers
- Transitional - distensible type cells that can change shape.
17
Q
Simple squamos cells:
- Normally play a passive role allowing for the exchange of [] and [] across their membrane
- 2 distinction
- [] lines all blood/lymphatic vessels and the heart in the body
- [] lines the body cavities
A
- gas and nutrients
- 2 distinctions
- Endothelial
- Mesothelial
18
Q
Simple Cuboidal Cells:
- Frequently engaged in [] transport or synthesis of [] products
- With increased cytoplasmic volume (compared to squamos cells) they have more [], [] (organelles)
A
- active; secretory
- Mitochondria, ER
19
Q
Simple Columnar Cells:
- Frequently have either [], [], or [] function
- Nuclei tend to line up in a [] fashion
- Occur on surfaces of [] curvature than cuboidal cells
- [] or [] cells occur in columnar cells…these are unicellular glands
A
- protective, absorptive, secretory
- Polarized
- Less
- Mucous or goblet cells
20
Q
T/F
Pseudostratified Epithelia still consists of cells that reach from the basement membrane to the free surface of the cell?
A
False
Not all cells reach the free surface in pseudostratified Epithelia
21
Q
Where are the main places you could find pseudostratified columnar epithelia?
A
- Respiratory Tract (with cilia AND Goblet cells
- Male Reproductive System
- Epididymus (with stereocilia)
- Efferent Ductules (with Cilia)
- Ductus deferens (with cilia)
22
Q
What type of pseudostratified columnar cells can be found in these locations?
- Respiratory Tract
- Epididymis
- Efferent Ductules
- Ductus Deferens
A
- ciliated pseudostratified columnar epithelium with goblet cells
- pseudostratified columnar epithelium with stereocilia
- Ciliated pseudostratified columnar epithelium
- Ciliated
23
Q
What is the function of stratified squamos cells?
A
Protection from abrasion, desiccation
24
Q
What type of cell layer is a cornified epithelial??
A
Keratinized dead cell layer
25
What characterization of cells would you find on large ducts of various glands like sweat glands, pancreas, and the parotid glands?
Stratified Cuboidal
26
Where you would find stratified columnar cells?
They are rare, but you'd find them in large ducts and in **transition zones** in the pancreas and parotid gland
Ex: Rectal-anal junction
27
1. Transitional cells are almost exculsively found in these 3 places?
2. Function Example: if the bladder is full...what would these cells look like?
3. Can these cells be bi-nucleated?
1. Bladder, Ureter, Renal Pelvis
2. They would be flattened. If the bladder was empty, these would be scalloped
3. Yes!
28
What apical modifications are made to epethial for, protection, absorption, locomotion?
* Protection
* Cornified
* Absorption
* Microvilli
* stereocilia
* Locomotion
* Flagella
* Cilia
29
The glycocalyx helps being what process for epithelia cells?
Absoprtion
30
Microvilli
1. Have a [] core
2. Are involved in the process of []
3. In the intestines it is called [] and in the kidneys it is called []
4. They are attached to [] [] within the cell to give structural strength
1. actin core
2. absoprtion
3. striated border; Brush Border
4. Intermediate Filaments
31
Stereocilia
1. Mainly found in the []
2. Much longer than [] @ 3-120 um!
3. Its core is [] (but less than microvilli)
4. The protein [] anchors the filaments
5. It has a [] in function except for in the []
1. Hear it helps keep balance using the the ear []
1. epididymus
2. Microvilli
3. actin
4. ezrin
5. Absorptive; ear
1. ear fluids
32
[] are complex hair like motile structures, .25 um in diameter and up to 10 um long.
Cilia
33
Cilia:
1. Originate from an MTOC called the []
2. Have [] pairs of microtubules and a set of [] as the core of the cilia
1. This structure is known as []
3. Movement of cilia in "circular" motion is driven by [] which is attached to the seperate 9+2 microtubule pieces
1. Basal Body
2. 9; 2
1. Axoneme
3. Dynein
34
What is the structure of the axoneme of the basal body in which Cilia arise from?
9 + 0 triplets.
So, 9 tripleys make a ring around the outside with not MTs in the middle
35
What are the 3 types of Lateral Membrane Modifications?
1. Barrier-Seal
2. Mechanical Anchors
3. Communicating Junctions
36
What type of lateral modification is responsible for intercellular adhesion?
What are some specific examples of these?
1. Mechanical Anchors
1. Zonula Adherens, Macula Adherens (Cell-to-Cell)
2. Focal Adhesions, Hemidesmosomes (Cell-to-Extracellular
37
What type of lateral modification is a Gap Junction?
What is the gap junction's function?
* Communicating Junctions
* Function is to allow cell sto communicate with each other using different small, ionic signals
38
What are the 3 surface cellular attachments?
What is each attachment used for
1. Intercellular Glu - **Glycocalyx**
1. ****Cell-to-cell adhesion
2. Apical Junction Complex
1. Used for adhesion to each and for communication
3. Gap Junction
1. Used for communication
39
The [] is involved in regulating cell-cell adhesion, paracellular permeability and cell polarity. It has 3 parts...
Apical Junction Complex
40
What are the 3 parts to the Apical Junction complex?
1. Zonula Occludens
2. Zonula Adherens
3. Macula Adherens
41
1. Zonula Occludens is another name for []
2. These restrict passage of materials [] the cells
3. Possess 3 protiens
1. [], [], and []
1. Tight Junction
2. between
3. Claudin, Occludens, JAMs (Junctional Adhesion Molecules
42
Zonal Occludens Proteins do what...
1. Claudin
2. Occluden
3. Junctional Adhesion Molecule
1. Allows for some passage. But is regulated/**specific**
2. Does not allow anything through between cells
3. provide a transmemebrane linkage
43
The expression and localization of Zonula Occludens proteins are regulated by signaling pathways including:
[], [], and []
Calcium
Phosphorylation
G-proteins
44
T/F
The Zonula Occludens is a passive structure, especially around the brain?
* False!
* It is an active structure that is regulated by calcium, phosphorylation, and G-proteins
45
1. Another name for Zonula Adherens - []
2. These provide lateral adhesion by linking together the [] [] between the cells
3. The protein that defines their location is []
1. This is regulated by []
2. It binds to the [] of adjacent cells
1. Close Junction
2. **actin cytoskeleton**
3. Cadherin
1. Calcium
2. Microfilament
46
The actin connections to which Lateral junction provide the anchor site for actin based filament cores of microvilli??
Zonula Adherens
47
1. These junctions are punctate sites of mechanical cell adhesion
2. Commonly found in [] squamos epithelial
3. Another name for them is []
4. Their mechanical adhesion is due to the linkage of [] [] via the glycoproteins
1. [] and []
1. Macula Adherens
2. stratified
3. desmosomes
4. intermediate filaments
1. desmocollin
2. desmoglein
48
Desmosomes regulate:
1. Morphogenetic []
2. Cell []
3. Wound []
1. morphogenetic development
2. Cell Differntiation
3. Wound regeneration
49
[] are found on cell surfaces that face the basement membranes
Hemidesomosomes
50
Hemidesmosome:
1. Provide for mechanical adhesion to [] []
2. The junction is made up of [] proteins
1. basal lamina
2. Integrin
51
How do desmosomes and hemidesmosomes differ?
* Desmosome
* Plaque is made of cadherins
* Mechanical adhesion to intermediate filaments --\> Plasma Membrane
* Hemidesmosome
* Plaque is made of integrins
* Mechanical adhesion to basal lamina
52
How many **connexins** are on each side of a gap junction?
6
53
What are the purposes of Gap Junctions?
* Cell-to-Cell communication via ionic cell coupling
* Allow cell-cell direct cytoplasmic coninuity
* Close on death
* Nexus - muscle/nerve interactions
54
Are Gap Junctions inactive or active?
* These junctions are **active**
* They can be regulated to open/close via pH and C2+ ions
55
What causes basal infoldings in a cell?
* These are infoldings meant to increase the surface area of the membrane.
* These membranes are found in cells that are active in fluid transportation (Na+, K+ ATPase)
* Found in salivary glands
* Mitochondria provide energy
56
What are the 2 components of the Basement Membrane?
Where does each component originate from?
1. Basal Lamina
1. Epithelial origin
2. Reticular Lamina
1. CT origin
57
Another name for the basal lamina - []
Lamina Densa
58
What are the 2 types of basal anchoring junctions?
How dow they anchor?
1. Hemidesmosomes
1. Anchors **intermediate filaments** to extracellular matrix
2. Focal Adhesions
1. Binds **actin** to extracellular matrix
59
Functions of the Basement Membrane:
1. Highway for cell []
2. Stabilize cell [] (acts as an anchor)
3. Control growth- [] in malignancy
4. [] & Filtration
5. Selective [] barrier
6. Signaling - [] adhesions
1. migration
2. shape
3. breakdown
4. nutrition
5. permeability
6. Focal adhesions
60
The Focal adhesions bind actin to extracellular components via which protiens...
* integrins
* alpha-actinin
* Vinculin
* Paxillin
* talin
61
Glands develop from an [] surface and are composed of 2 final types:
1. Exocrine - (explain)
2. Endocrine (explain)
* epithelial
* **Exocrine** - develop and then stay associated with epithelium
* **Endocrine** - develop and then differentiate from epithelium
* usually surrounded by vascular tissues and stuff
62
What are the 2 types of cellsin glandular epithelia, and what are their functions?
1. **Parenchyma -** functional (secretory), epithelia
2. **Stroma -** supporting cells, connective tissue
63
Glands that invaginate from the epithelial surface then create and release products into a duct system are referred to as [] glands
exocrine
64
Glandular epithelia that release their product into the blood stream via CT are referred to as [] glands
Endocrine
65
1. What is an example of a unicellular gland
2. What does it produce
3. It is [] polarized
4. Where is it located?
1. Goblet Cells
2. Mucus
3. Highly
4. Respiratory & GI systems
66
Multicellular glands are composed of two populations...what are they?
* Parenchyma
* Stroma
67
How do we classify Exocrine glands?
* **Ducts**
* Simple-unbranched
* Compound - branched
* **Morphology**
* Tubular - short/long
* Acinous or alveolar - round
* Compound - both acinous or alveolar
* **Nature of Secretion**
* Serous - round nuclei, water, enzymes
* Mucous - flatten nuclei
* Mixed
68
Serous glands are usually [] in shape and will be stained [] by an Eosin stain?
Why does Eosin stain these?
1. cuboidal; red
2. Eosin stains these becuase it is an Acidic stain. Proteins, and enzymes are basic. A a serous gland is producing product to release, which probably takes a lot of proteins/enzymes....
69
What color stain do the mucous secreting cells of the exocrine gland produce?
None really. The mucus doesnt stain.
70
The products of serous glands are usually stored as what?
**Zymogen granules** (secretory precursor)
71
Mucous Glands have a [] nuclei
flattened
72
Where are mixed mucous and serous glandular tissue found?
* Pancrease and salivary gland (submandibular)
73
What are the 3 types of exocrine gland secretion release?
How does each work?
1. **Apocrine**
1. The product is secreted in a "bleb" from the parent cells plasma membrane
2. **Holocrine**
1. Product is released and cell basically breaks apart and dies
3. **Merocrine**
1. Exocytosis - no loss of parent cell parts
74
What is an example of...?
Apocrine Secretion
Merocrine Secretion
Holocrine Secretion
1. Apocrine - mammary gland
2. Merocrine - most glands
3. Holocrine - sebaceous gland
75
These cell's population is....
Static:
Expanding:
Renewing:
1. Muscle/Nerve
2. Liver/Kidney
3. Blood, skin gut
76
What is the time to replace these region of epithelial?
1. Small Intestine
2. Epidermis
3. Trachea
4. Bladder
1. 3.4 days
2. 19.2 days
3. 47.6 days
4. 66.5 days
77
What are the 2 distinct type of Endocrine glands?
Examples of each?
* **Cords/Clusters**
* Islets of Langerhans in the pancrease
* Adrenal Cortex
* **Follicles**
* Secretory products are stored in a hallow chamber
* Thyroid gland
