Epithelial Tissue Flashcards

1
Q

Avascular tissue is composed of cells that: (4)

A

o cover the exterior body surfaces
o line the internal closed cavities including the vascular system
o line body tubes that communicate with the exterior (GIT, urogenital and respiratory tracts)
o form secretory portions and ducts of glands

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2
Q

What are the defining characteristics of epithelial tissue?

A
  1. Cells are in close apposition and have little extracellular matrix
  2. Functional and morphologic polarity
    o Cells have 3 domains- apical domain, lateral domain and basal domain
  3. Cells adhere strongly by specialized cell junctions
  4. Cell basal surface attaches to basement membrane
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3
Q

What is epithelioid tissue? (2)

A

o Cells that are closely apposed and have a basement membrane but lack a free surface
o Present as most endocrine glands

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4
Q

How does epithelium function as a selective barrier?

A

Epithelia covering and lining surfaces form a sheet-like cellular investment that separates underlying connective tissue from the external environment, internal cavities or fluid connective tissue (blood or lymph)

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5
Q

What are the functions of epithelia? (5)

A
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6
Q

How does the classification of epithelial tissue take place?

A
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7
Q

Simple squamous:
Image
Locations
Functions

A
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8
Q

Simple cuboidal:
Image
Locations
Functions

A
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9
Q

Simple columnar:
Image
Locations
Functions

A
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10
Q

Pseudostratified columnar:
Image
Locations
Functions

A
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11
Q

Stratified squamous:
Image
Locations
Functions

A
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12
Q

Stratified cuboidal:
Image
Locations
Functions

A
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13
Q

Transitional (urothelium):
Image
Locations
Functions

A
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14
Q
  • Epithelia may also be classified according to its _____ specialisations if present
  • Some exocrine glands have cells that are _____ in shape
  • These cells are still classified as either columnar or cuboidal
A

apical
pyramidal

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15
Q

In stratified epithelium:
o The cell ____ and ____ vary from layer to layer
o Only the shape of the cells that form the surface layer is used in classification.

A

height
shape

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16
Q

What are the SPECIAL classifications of epithelia? (2)

A
  1. Pseudostratified epithelium
    o Nuclei are at different levels and some cells do not reach the free surface
    o Since all cells rest on the basement membrane, it is regarded as a simple epithelium
  2. Transitional epithelium (urothelium)
    o Stratified epithelium with special
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17
Q

Simple squamous epithelia in specific locations:
1. Endothelium-
2. Endocardium-
3. Mesothelium-

A

lining of the blood and lymphatic vessels

lining of the ventricles and atria of the heart

lining of the walls of the abdominal, pericardial and pleural cavities

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18
Q
  • Specific _____ characteristics are associated with each cell surface
  • The free apical domain is always directed toward the exterior surface of the lumen of an enclosed cavity or tube
  • The lateral domain ________ with adjacent cells and has specialised attachment areas
  • The basal domain rests on the ______ _____ anchoring the cell to underlying connective tissue
A

biochemical
communicates
basal lamina

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19
Q

What are the Apical Domain Specializations? (3)

A
  1. Microvilli
  2. Stereocilia (stereovilli)
  3. Cilia
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20
Q

What are microvilli? (5)

A
  • Cytoplasmic processes containing a core of actin filaments
  • Functions in increasing surface area for absorption
  • In kidney tubules- brush border
  • In GIT- striated border
  • Also located in brain ependyma
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21
Q

What are Stereocilia (stereovilli)? (3)

A
  • Microvilli of unusual length (very long)
  • Functions in facilitating absorption and mechanoreception
  • Limited to male reproductive system and sensory hair cells in the ear
22
Q

What are cilia? (4)

A
  • Motile cytoplasmic processes
  • Contains the motor protein dynein
  • Core of microtubules in 9+2 pattern
  • Functions in transportation
23
Q

Where are cilia found? (4)

A

o Oviducts
o Trachea and bronchi
o Brain ependyma
o Olfactory epithelium

24
Q

Zonula Occludens (tight junction):
Image
Cytoskeleton Component
Functions

A
25
Q

Zonula Adherens:
Image
Cytoskeleton Component
Functions

A
26
Q

Macula Adherens (desmosome):
Image
Cytoskeleton Component
Functions

A
27
Q

Focal adhesions vs Hemidesmosomes
Image
Cytoskeleton Component
Functions

A
28
Q

Gap junction (nexus)
Image
Cytoskeleton Component
Functions

A
29
Q

True or false
Basement membrane
* Visible on light microscope with Periodic Acid-Schiff staining technique as magenta

A

True

30
Q

What is the structure and composition of the basal lamina? (2)

A

o Structural attachment site for overlying epithelial cells and underlying connective tissue
o Composed of laminins, type IV collagen, proteoglycans and glycoproteins

31
Q

What is the function of basal cell membrane infoldings? (4)

A
  • Increase surface area of basal domain
  • Allows for more transport proteins and channels to be present
  • Prominent in cells that participate in active transport of molecules (kidney tubules and salivary
    glands)
  • Orientation of mitochondria together with infoldings results in striated appearance
32
Q

What are the staining techniques?

A
33
Q

What are the types of Glandular Epithelium?

A
34
Q

Classification by mode of secretion: (3)

A
  1. Merocrine secretion
  2. Apocrine secretion
  3. Holocrine secretion
35
Q

What is Merocrine secretion? (4)

A
  • Delivered in membrane-bound vesicles to the apical surface
  • Vesicles fuse with cell membrane
  • Contents are extruded via exocytosis
  • Most common mode of secretion
36
Q

What is Apocrine secretion? (3)

A
  • Product is release in apical portion of the cell
  • A thin layer of cytoplasm within an envelope of cell membrane pinches off from the cell
  • Found in lactating mammary gland and armpit and groin area
37
Q

What is Holocrine secretion? (4)

A
  • Product accumulates within the maturing cell
  • The cell undergoes apoptosis and lyses
  • Product and cell debris is released into the lumen of the gland
  • Found in sebaceous glands and tarsal (Meibomian) glands of the eyelid
38
Q

What are the types of simple glands?

A
39
Q

What are the types of compound glands?

A
40
Q

Simple tubular gland:
Image
Typical Location
Features

A
41
Q

Simple coiled tubular gland:
Image
Typical Location
Features

A
42
Q

Simple branched tubular gland:
Image
Typical Location
Features

A
43
Q

Simple alveolar gland:
Image
Typical Location
Features

A
44
Q

Simple branched alveolar gland:
Image
Typical Location
Features

A
45
Q

Compound tubular gland:
Image
Typical Location
Features

A
46
Q

Compound alveolar gland:
Image
Typical Location
Features

A
47
Q

Compound tubulo-alveolar gland:
Image
Typical Location
Features

A
48
Q

What is mucus secretion? (6)

A
49
Q

What is serous secretion? (5)

A
50
Q

Where is Mucoserous found?

A

Found in submandibular (tubule-alveolar) glands

51
Q

What are Myoepithelial cells? (6)

A
  • Contractile
  • Have actin filaments
  • Surround SEPs
  • Located in between basement membrane and basal part of secretory cells
  • Have a squashed appearance
  • Stain darkly