Epithelial Tissue Flashcards

1
Q

What are the different types of epithelia?

A

Surface (lining) epithelia

Glandular Epithelia

Germinal Epithelia

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2
Q

What is the function of surface (lining) epithelia?

A

Form external surface - body and many organs

Form internal lining of hollow tubes - ducts, vessels, tracts

Form internal lining of body cavities

Specialized surface epithelia contain touch receptors and may contain receptors for senses

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3
Q

What is the function of glandular epithelia?

A

Secrete glandular products exocrine and endocrine

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4
Q

What is the function of germinal epithelia?

A

Generate gametes and foster their maturation/development (ovaries, testes only)

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5
Q

What epithelia are highly active both metabolically and synthetically?

A

Glandular and germinal

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6
Q

All epithelia have high ___

A

Turnover

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7
Q

Where do most tumors derive from?

A

Epithelial Tissue

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8
Q

What are 3 benign epithelial tumors?

A
  1. Adenomas
  2. Papillomas
  3. Polyps
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9
Q

What are defining characteristics of epithelia? x 7

A

Highly cellular - high cells to ECM ratio

Basement Membrane (BM)

Polarity: Apical, Lateral, and Basal Domains

Cell Junctions

Avascular

Intermediate Filaments made of keratin

Often have apical surface modifications - cilia

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10
Q

What is the basement membrane of epithelium?

A

Interface between epithelium and underlying connective tissue. Most of ECM of epithelia

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11
Q

What are the functions of the basement membrane?

A

Provides structural support

Physical Barrier

Metabolite diffusion

Helps regulates epithelial growth and differentiation

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12
Q

What are three layers of the basement membrane?

A

Lamina Lucida

Lamina Densa

Lamina fibroreticularis

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13
Q

What are the characteristics of the lamina lucida?

A

Multi-adhesive glycoproteins - laminins

Electron lucent

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14
Q

What are the characteristics of lamina dense?

A

Collagen IV - mesh forming collagen, abundant in basement membrane

GAGs

Electron dense

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15
Q

What are the characteristics of lamina fibroreticularis?

A

Collagen III fibrils - reticular fibers

Collagen VII - anchoring fibrils. Helps anchor lamina densa to underlying connective tissue

Collagen I - small amounts

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16
Q

What is the basal lamina? What is its function?

A

Lamina lucida and lamina densa only

Flexible support for overlying epithelium. Anchors cells to basement membrane. Molecular filter

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17
Q

How does the lamina lucida stain?

A

Laminins - PAS positie

18
Q

How does the lamina densa stain?

A

Collagen IV - IHC and PAS positive

Sulfated GAGs - metachromatic and PAS+

19
Q

How does the lamina fibroreticularis stain?

A

Collagen III - Argyrophilic and PAS positive

Collagen VII

Collagen I - weakly acidophilic

20
Q

What are simple epithelia?

A

1 layer of cells

21
Q

What are stratified epithelia?

A

2 or more cell layers

22
Q

What is pseudostratified epithelia?

A

Have 1 layer but looks like more than 1 layer

23
Q

What are the functions and locations of simple squamous epithelia?

A

Functions - Diffusion, form linings, and secrete serous fluid for lubrication

Locations: Lining body cavities, vessels, alveoli, Bowman’s capsules, and heart chambers

24
Q

What is the structure and what are the functions and locations of simple cuboidal cells?

A

Square - as tall as it is wide

Functions - absorption, secretion, and conduits (forms wall of small ducts)

Locations - Ducts in exocrine glands, renal tubes, thyroid follicles

25
What is the structure, function, and location of simple columnar epithelia?
Appear like columns, taller than they are wide Functions - absorption, secretion, conduits Locations (noncilia) - stomach, intestines, gallbladder Locations (cilia) - Oviducts
26
What is the structure, function, and location of stratified squamous?
2 or more layers with cells near basal domain being more cuboidal and get flatter as you go towards apical domain. Functions - barrier and protections and abrasion Locations (nonkeratinized) - esophagus, vagina, cervix, distal anal canal Locations (keratin) - epidermis
27
What is the function and location of stratified cuboidal and columnar epithelia?
Function - barrier and conduit Locations - largest ducts of exocrine glands, anal-rectal junction
28
What is the structure, function, and location of transitional (urothelium) epithelia?
Appear pillow-like Function - stretching and urine-proof barrier, proteins on surface allow it to stretch Locations - Ureters, urinary bladder, urethra
29
What is the function and location of pseudostratified columnar?
Functions - secretion, absorption, barrier, conduit Locations - trachea, bronchi, and ducts of male reproductive system
30
What are examples of apical surface specialization in the apical end of epithelial tissue?
Keratinization Goblet cells
31
What are examples of apical surface specialization in the apical end of individual cells?
Cilia Microvilli Stereocillia
32
Where does keratinization occur and how do they appear in TEM?
Stratified Squamous Keratinized tissue will have no nuclei in apical most layers and apical layers appear flakey
33
What are goblet cells? What is their function and where are they located?
Goblet cells are modified simple columnar cells Function - Secrete mucinogen Locations - Respiratory tract, Intestinal tract, conjunctiva of eyelid
34
What are the 3 kinds of cilia?
Motile (M) Primary (P) Nodal (N)
35
What is the function, location, and movement of motile cilia and flagella?
Function - transport (of eggs, mucus, ) and movement (sperm) Locations - many Movement - Active, back and forth, synchronous waves, flagella undulate
36
What is the structure of cilia?
9x2 array with 2 microtubules in middle Linker proteins Microtubules - tubulin Motor proteins - dynein Basal body - 9x3 array that stabilizes microtubules and secretes tubulin Striated rootlet - anchors basal body into cytoplasm
37
What is the structure, function, location, and movement of monocilia?
9x2 microtubule array with no motor proteins. 1 per cell Function - sensory antenna, role in tissue morphogenesis Location - nearly every cell Movement - no active movement, passive bending in fluid
38
What is the structure, function, location, and movement of nodal cilia?
Structure - 9x2 array with motor proteins (dynein) Function - helps develop R to L asymmetry of internal organs in the embryo by circulating morphogens (Shh, retinoic acid) Location - Embryo- gastrulation from primitive node Movement - Active. Rotate counterclockwise
39
What is the function, location, and movement microvilli?
Striated border in LM Function - increase surface area for absorption Locations - most epithelial cells -> more obvious in LM in kidney tubules and intestine Movement - nonmotile, can be moved passively by contracting the terminal web
40
What is the structure of microvilli?
Core of each microvillus has 20-30 vertical and parallel actin (thin) filaments anchored by proteins (fimbrin, espin) to maintain parallel oritentation. Anchored to cell membrane at tips and sides by villin and myosin I. No motor proteins. Myosin II in terminal web - contracts and draws base close together, tips spread, and fluid flow increases between microvilli
41
What is the structure, function, location, and movement stereocilia?
Structure - Very long microvilli Function - absorption (male reproductive tract), mechanoreception (ear) Locations - epididymis, proimal ductus deferens, inner ear Movement - nonmotile, no motor proteins, no myosin, can be moved passively by fluid flow or fluid vibration