Varb 5180 Micro Anatomy: Epithelium

Front 1

Define: Tissue

Back 1

A group of cells and cell products which have similar structure and perform similar functions.

Front 2

What are the four basic tissue types?

Back 2

1) Epithelium
2) Connective tissue
3) Muscle
4) Nervous tissue

Front 3

Where are each of the four basic tissue types derived from?

Back 3

1) Epithelium= ectoderm, endoderm, mesoderm (special)
2) Connective tissue= mesoderm
3) Muscle= mesoderm
4) Nervous tissue= ectoderm

Front 4

Define: Parenchyma

Back 4

The cells which make the functional units of an organ.

Front 5

Define: Stroma

Back 5

The connective tissue framework associated with the epithelium.

Front 6

Define: Serosa (serous membrane)

Back 6

Specialized epithelia and its associated connective tissue which line the external surfaces of body tubes with an external connection.

Front 7

Define: Mucosa (mucous membrane)

Back 7

Specialized epithelia and its associated connective tissue which line the luminal surfaces of body tubes with an external connection and secrete thick viscous fluid.

Front 8

Define: Lumen

Back 8

Space contained within a tube, cylinder, or sphere.

Front 9

Define: Polarity

Back 9

Fixed segments of the cell's borders different from one another.

Front 10

Define: Apex/apical

Back 10

The luminal border or surface.

Front 11

Define: Base/basal

Back 11

Adjacent to the basement membrane and underlying connective tissue matrix.

Front 12

Define: Lateral

Back 12

Lateral side of cell, attachment to adjacent cells.

Front 13

Characteristic of Epithelium

Back 13

Lines surfaces of organs, forms individual glands and entire glandular organs.Very little intercellular space; contiguous, high density. Rest ona basal lamina.

Front 14

Define: Basal lamina

Back 14

A highly specialized connective tissue matrix which attaches cells to underlying substrata.

Front 15

List the functions of epithelial tissues

Back 15

1) Protection
2) Absorption
3) Excretion
4) Secretion
5) Surface reception
6) Reproduction

Front 16

List the ways epithelial tissue is classified

Back 16

1) Number of layers
a) Simple
b) Stratified
2) Cell shape
a) Squamous
b) Cuboidal
c) Columnar

Front 17

What are the special types of simple squamous epithelium?

Back 17

1) Mesothelium
2) Endothelium

Front 18

Define: Mesothelium

Back 18

Specialized simple squamous epi. that lines the inner surfaces of some body cavities, and out surfaces of internal organs. Makes smooth surfaces between mobile viscera. Mesoderm derived.

Front 19

Define: Endothelium

Back 19

Specialized simple squamous epi. that lines all blood vessels, heart, and lymphatics. Prevents spontaneous clotting. Site of attachment for migrating inflammatory cells. Mesoderm derived.

Front 20

What are some characteristics of simple cuboidal epithelium?

Back 20

-Line kidney tubules, parts of the respiratory tract.
-Duct lining
-Functions: secretion and absorption

Front 21

What are some characteristics of simple columnar epithelium?

Back 21

-Line the stomach, intestines, parts of the respiratory tract, and glands.
-Functions in secretion and absorption.

Front 22

What are some characteristics of stratified squamous epithelium?

Back 22

-Basally located cells often thicker in appearance than apically located.
-Specialized to resist forces of friction.
-2 types: Keratinized and non-keratinized

Front 23

What are some characteristics of keratinized stratified squamous epithelium?

Back 23

-Lines external body surfaces, buccal cavity, forestomach in ruminants.
-Cell nuclei not visible in apical layers; replaced with a substance that resists abrasive forces and resists loss of water.

Front 24

What are some characteristics of non-keratinized stratified squamous epithelium?

Back 24

-Lining the vestibular region of the respiratory tract, esophagus, cornea, and portions of the urogenital tract.
-Cell nuclei are present in apical layers.

Front 25

What are some characteristics of pseudostratified columner epithelium?

Back 25

-Cells irregular in shape and size, nuclei located at various levels.
-Simple, NOT stratified
-Can be ciliated
-Found in respiratory and urogenital tracts, and lining some ducts.

Front 26

What are some characteristics of transitional epithelium?

Back 26

-Simple in classification
-Found in urogenital tract
-Can stretch
-Cobblestone appearance

Front 27

What are the types of anchoring junctions?

Back 27

1) Desmosomes (macula adherens)
-Hemidesmosomes
2) Zonula adherens

Front 28

What are some characteristics of desmosomes?

Back 28

-"adhering spot"
-Space between adjacent plasma membranes
-Have cytoplasmic dense plaques (adhesion plaques)
-Intermediate filaments mechanically reinforce area of attachment by anchoring the plaques to the structural proteins of the cell cytoplasm

Front 29

What is a hemidesmosome?

Back 29

-"Half a desmosome"
-Between a cell and the extracellular matrix (basement membrane) at the basilar surface

Front 30

What are some characteristics of zonula adherens?

Back 30

Lack a visible attachment plaque between the adjacent cells which is replaced by an "adhesive" material and circumscribe whole cell

Front 31

What are the types of intercellular junctions?

Back 31

1) Anchoring junctions
2) Occluding junctions
3) Communicating junctions

Front 32

What are some characteristics of occluding junctions?

Back 32

-aka tight junctions, zonula occludens
-External laminae of plasma membrane of contiguous cells are shared at periodic points
-Act as an effective barrier against materials passing from luminal to basilar sides between adjacent cells

Front 33

What are some characteristics of communicating (gap) junctions?

Back 33

-Chemical synapses
-2 nm space b/t adjacent cells
-interrupted by small, regularly spaced arrays of hexagonal subunits which form actual channels between cells

Front 34

What are junctional complexes?

Back 34

-A dense region at the apical pole of adjacent epithelial cells as seen by LM.
-Resolvable to a group of 3 structures: macula adherens, zonula adherens, and zonula occludens

Front 35

What are the types of surface modifications?

Back 35

1) Intercellular junctions
2) Basal infoldings and lateral interdigitations
3) Basal lamina
4) Apical surface modifications

Front 36

What are the types of apical surface modifications?

Back 36

1) Microvilli
2) Stereocilia
3) Cilia
4) Flagella

Front 37

What are some characteristics of basal infoldings and lateral interdigitations?

Back 37

-Parallel convolutions of the opposing plasma membranes
-Increase intercellular contact surface area to facilitate attachment and "communication"

Front 38

What are the functions of the basal lamina?

Back 38

Cell adhesion, diffusion barrier, and cell growth.

Front 39

What are some characteristics of basal lamina?

Back 39

-Composed of unique molecules not found in other CT matrices such as type IV collagen, laminin, entactin, and specific proteoglycans.

Front 40

What are some characteristics of microvilli?

Back 40

-Increase SA and involved in absorption
-Tiny surface projections at the apical pole of the cell.
-Plasma membrane anchored to microfilaments found in the core of the process.

Front 41

Define: Glycocalyx

Back 41

A coating of glycoproteins and other complex sugars which cover the external surface of the apical plasma membrane.

Front 42

What are some characteristics of stereocilia?

Back 42

-Increase SA
-Non-motile, specialized surface projections
-Considered to be very long microvilli

Front 43

What are some characteristics of cilia?

Back 43

-Highly motile, apical surface projection

Front 44

What is an axoneme?

Back 44

A cylindrical array of microtubules, consisting of 9 "doublets" of microtubules around two single centrally located microtubules.

Front 45

What are some characteristics of flagellum?

Back 45

-Same structure, but fewer in number than cilia