Epithelia Flashcards

1
Q

Sheets of cells that cover external surfaces and line internal surfaces of the body

A

Surface Epithelium

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2
Q

Secretory cells of glands

A

Glandular Epithelium

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3
Q

Where is epithelium present?

A

Present on surface of skin as well as organs who have communication with external environment

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4
Q

Single layer of flattened, scale-, or plate-like cells - nuclei often flattened or ovoid

A

Simple Squamous Epi. - the large body cavities such as heart, blood vessels, and lymph vessels typically have this

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5
Q

Simple cuboidal epi

A

cells appear cuboidal in sections perpendicular to surface - from surface look like small polygons -Occurs in small excretory ducts of many glands, follicles of thyroid glands, tubules of kidney and on surface of ovaries

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6
Q

Cells that are taller than wide - single layer

A

Simple Columnar Epi: - nuclei of cells within epi are usually located at the same height within cells - often close to base of the cells - internal surface of large and small intestine

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7
Q

What type of epithelium layer is this?

A

Stratified squamous Epi:

  • named from the cells at the surface
  • appear like flat scales - same as simple squamous but more layered now
  • most apical layer lose nucleus = dead, make up a tough layer called keratin instead
  • specialized in mammalian skin
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8
Q

What type of epi layer is this?

A

Transitional Epi:

  • is unique and found exclusively in the excretory urinary passage
  • in a relaxed state: appear cubidal or columnar in shape
  • in a distended state: resemble a stratified squamous epi
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9
Q

What type of epi layer is this?

A

Pseudostratified columnar epithelium:

  • all cells are in contact with basement membrane - BUT - not all reach the surface of the epi.
  • the nuclei of cells that do not reach the surface are often located in different heights within the epithelium and give it a stratified appearance but it is NOT

- found in the excretory ducts of many glands

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10
Q

Name the 3 difference surfaces of a cell:

A

top: apical (free) surface
middle: lateral (or contact) surfaces - neighbourning epithelial cells
bottom: basal surface
- rests on basement membrane

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11
Q

What is the basement membrane?

A

membrane that the basal surface of cells is connected to.

  • made up of an extracellular supporting layer = function is support
  • basement membrane also acts as a selectively permeable filter between epithelium and connective tissue
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12
Q

What are microvilli and stereocilia?

A
  • non-motile finger- or thread-shaped extensions of epithelial cells
  • main function: increase surace area of cells active in absorption
  • micro are much shorter than stereo
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13
Q

What are motile strucutres that beat in a synchronous manner to move material across epi surfaces?

A

Cilia

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14
Q

Name an Occuluding type junctional complex

A
  • Tight junctions: connects adjacent cells; close to apical surface
  • form very tight connection with neighbouring cells
  • stop all movement to basement membrane
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15
Q

What are teh 2 adhering type junctional complexes?

A
  • Desmosomes/zonulae adherens: anchor cells to each other; connected to cytoskeleton
  • Hemidesmosomes: connect cells to basement membrane
    • not combining with another cell - but binding into place
  • both are found in lateral surfaces
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16
Q

What is a Gap junction?

A
  • A communicating type junctional complex
  • allows movement of small molecules from one cell to an adjacent cell
17
Q

What are the two type of glands?

A

Exocrine

Endocrine

18
Q

Release secretory product via a system of ducts that open onto the surfaces of the body which are in contact with the external world?

A

Exocrine glands

  • e.g. milk, mucus, sweat
  • derived from epi layer same as endo - but maintains it’s connection with the surface epithelium
19
Q

release their secretory product (typically hormones) into the spaces between the secretory cells from which it enters the bloodstream

A

Endocrine glands

  • derives from epi layer but loses its connection with the surface epithelium
20
Q

Secretory method that product moves to cell membrane, joins it and released into surrounding duct without any structural loss

A

Merocrine

21
Q

secretory method that moves to surface, surrounded by membrane - then loss of some of its cytoplasm

A

Apocrine

22
Q

secretory method where whole cell explodes basically

A

Holocrine

23
Q

what type of muscle is this?

  • mononucleus
A

Smooth muscle

24
Q

What type of muscle is below?

  • mononucleic
A

Cardiac muscle:

mononucleic, striated

25
Q

What type of muscle is below?

striated, multiple nuclei

A

Skeletal muscle

  • very long muscle fibres = striations
  • mutlinucleic cells, peripherally located
26
Q

What are intercolated discs?

A

junctional complexes of cardiac muscle = area of iron transfer