Epithelium Note Cards

Question 1

Zonula Occludens
(S,F,L)

Answer 1

Structure: occluding, tight, impermeable junctions; cell membranes of adjacent cells are in contact with each other forming a web-like seal

Function: Sealing epitheleal cells together, preventing paracellular diffusion of materials, maintaining cell polarity

Location: Apical-most level of the lateral cell membrane (wraps around)

Question 2

Zonula Adherens
(S,F,L)

Answer 2

Structure: adhesion junctions, band-like adhesion sites, close adjacent cell membranes, fuzzy plaques on cytoplasmic membrane made of actin filaments

Function: reinforcing cell-cell adhesion resisting separation between cells

Location: immediately below zona occuldens on lateral cell membrane

Question 3

Desmosomes (Macula Adherens)
(S,F,L)

Answer 3

Structure: space ebtween cells with electron-dense lins, dense plaque of intermediate filaments on cytoplasmic membrane

Function: anchoring adjacent cells together, reinforcing cell-cell adhesion, resisting separation

Location: scattered throughout lateral membrane below zonula adherens

Question 4

Gap Junctions
(S,F,L)

Answer 4

Structure: communicating junctions between adjacent cell membanes in close proximity

Function: allowing direct passage of signaling molecules between cells

Location: scattered throughout lateral membrane below zonula adherens

Question 5

Hemidesmosomes
(S,F,L)

Answer 5

Structure: intracellular plauqes similar to desmosomes with intermediate filaments

Function: anchoring epithelia to basement membrane and connective tissue, resisting abrasion force to prevent separating between epithelium and connective tissue

Location: basal cell surface

Question 6

Simple classifcation of cells
(S,F,L)

Answer 6

Structure: single layer of cells

Function: lining body cavity or glands, absorption, secretion

Location: areas that require quick transport of materials, large amounts of absorption or secretion

Question 7

Stratified classifcation of cells
(S,F,L)

Answer 7

Structure: more than one layer of cells

Function: lining, protecting areas of the body that need more strength and resistance

Location: areas that require more protection and strength

Question 8

Pseudostratified classifcation of cells
(S,F,L)

Answer 8

Structure: cells that appea stratfied but every cell contacts the basement membrane

Function: lining, absorption, secretion, creating current across epithelium

Location: areas that require movement of secretion or fluids, absorption and secretion

Question 9

Squamous shape of cells
(S,F,L)

Answer 9

Structure: flat cells with thin and wide cytoplasm and nuclei

Function: fast transport of molecules across cytoplasm, or protection in many layers

Location: areas that require rapid exchange of molecules or protection in many layers

Question 10

Cuboidal shape of cells
(S,F,L)

Answer 10

Structure: cube-shaped cells with central, spherical nuclei

Function: relatively fast absorption and secretion

Location: some exocrine and endocrine glands and ducts

Question 11

Columnar shape of cells
(S,F,L)

Answer 11

Structure: tall cells with central to basal, oval nuclei

Function: large amount of absorption and secretion

Location: lining of the intestine and respiratory tract

Question 12

Transitional epithelium
(S,F,L)

Answer 12

Structure: Number of layers and shape of the cells change based on the distention of the organ. Often have a “dome-like” appearance on apical surface; sometimes binucleate cells protruding out into the lumen on apical surface

Function: allowing distention an recoil of an organ

Location: urinary bladder, ureter, calyces, urethra

Question 13

Keratinazation
(S,F,L)

Answer 13

Structure: Layer of flattened, dead cells

Function: forming a protective layer against, force friction, and dessication

Location: areas exposed to repeated and prolonged exposure to force, friction, and air (outside of the body only

Question 14

Microvilli
(S,F,L)

Answer 14

Structure: Short, numerous cellular projections, contain actin

Function: increasing surface area of the luminal border

Location: areas the require large amount of absorption and secretion

Question 15

Cilia
(S,F,L)

Answer 15

Structure: Specialized cellular projections with motile mechanisms (axonemes)

Function: generating movements to create current

Location: areas that require movement of fluids over the epithelium

Question 16

Stereocilia
(S,F,L)

Answer 16

Structure: long, immotile cellular projections (have actin)

Function: increasing surface area for absoprtion and serving as mechano-receptors

Location: epididymis an special sensory epitheliun (inner ear)

Question 17

Simple squamous epithelium
(S,F,L)

Answer 17

Structure: single layer of flattened cells

Function: rapid exchange of gas, small lipid-soluble molecules and fluid

Location: luminal lining of vessels, lung alveoli, body cavity serous lining

Question 18

Simple cuboidal epithelium
(S,F,L)

Answer 18

Structure: single layer of cube-shaped cells

Function: relatively quick absorption and secretion

Location: kidney tubules, pancreatic acini, small ducts, thyroid follicles

Question 19

Non-ciliated Simple columnar epithelium
(S,F,L)

Answer 19

Structure: single layer of rectangular cells

Function: large amount of absorption, secretion, protection

Location: lining of glands of majority of gastrointestinal (GI) tracts

Question 20

Ciliated simple columnar epithelium
(S,F,L)

Answer 20

Structure: Single layer of rectangular cells with cilia on apical surface

Function: absorption, secretion, generation of current across the epithelium

Location: lining of fallopian tube

Question 21

Ciliated pseudostratified columnar epithelium
(S,F,L)

Answer 21

Structure: Single layer of ciliated colunar cells, other types of cells intermixed

Function: absorption, secretion, generation of current across the epithelium

Location: most of respiratory tract

Question 22

Keratinized stratified squamous epithelium
(S,F,L)

Answer 22

Structure: Thick layer of cells - flatted eosinophilic anucleate cells on apical surface, thick layer of cells below (may be in cuboidal shape on basement membrane)

Function: protection from repeated, prolonged exposure to force and friction, preventing dessication

Location: skin

Question 23

Non-Keratinized stratified squamous epithelium
(S,F,L)

Answer 23

Structure: Thick, layer of cells with flattened, nucleated cells on apical surface (may be cuboidal on basement membrane)

Function: protection from repeated, prolonged exposure to force and friction

Location: oral cavity, esophagus, vagina, anal canal

Question 24

Stratified cuboidal epithelium
(S,F,L)

Answer 24

Structure: Two or more layers of cuboidal cells

Function: maintaining the shape and patency of ducts

Location: interlobular and intralobular ducts

Question 25

Stratified colunar epithelium
(S,F,L)

Answer 25

Structure: two or more layers of rectangular cells

Function: maintaing the shape and patency of larger ducts

Location: terminal ducts

Question 26

Exocrine gland: Unicellular, single goblet shaped
(S,F,L)

Answer 26

Structure: within the lining epithelium, goblet shaped, nucleus near the bottom, clear near the top and eosinophilic on the sides; secreted directly into the lumen

Function: mucous secretion

Location: scattered withinin the lining of the epithelia of respiratory and GI tracts

Question 27

Exocrine gland: Simple tubular
(S,F,L)

Answer 27

Structure: test-tube shaped glands with simple columnar epithelium as the secretory unit

Function: mucous secretion

Location: small and large intestine

Question 28

Exocrine gland: Simple branched tubular
(S,F,L)

Answer 28

Structure: more than one test-tube shaped gland sharing a common duct or opening into a lumen; secretory units: simple colunar epithelium

Function: mostly mucous secreting

Location: stomach, pylorus

Question 29

Exocrine gland: simple coiled tubular
(S,F,L)

Answer 29

Structure: long, convoluted gland; secretory unit: simple cuboidal to stratified cuboidal epithelium, large, pale staining cells; duct: stratified cuboidal epithelium, smaller, dark staining cells

Function: sweat secretion

Location: skin sweat glands

Question 30

Exocrine gland: simple acinar
(S,F,L)

Answer 30

Structure: single, spherical gland draining into a short duct, secretory unit: simple cuboidal to columnar epithelium

Function: mucous secretion

Location: glands of litre near penile urethra

Question 31

Exocrine gland: simple branched acinar

Answer 31

Structure: more than one spherical gland draining into a common duct; secretory units: stratified cuboidal epithelium, cells are large and vacuolated

Function: sebum secretion

Location: skin sebaceous glands

Question 32

Exocrine gland: Compound tubular
(S,F,L)

Answer 32

Structure: More than one tubular gland and more than one duct opening into a lumen; secretory unit: simple columnar epithelium, pale-staining cells; ducts: simple columnar epithelium, dark-staining cells

Function: mucus secretion

Location: brunner glands of duodenum

Question 33

Exocrine gland: Compound acinar
(S,F,L)

Answer 33

Structure: More than one spherical gland, more than one duct of varying size; secretory units: simple cuboidal to pyramindal, most serous secreting cells filled with secretory granules; ducts: simple cuboidal, simple columnar, stratified columnar

Function: Watery proteinaceous secretion

Location:parotid glands, pancreas, mammary glands

Question 34

Exocrine gland: Compound tubuloacinar

Answer 34

Structure: More than one tubular and spherical gland, more than one duct of varying size; secretory units: simple columnar, simple cuboidal; demilunes (simple cuboidal columnar capped by hemispherical simple cuboidal acinar gland on ends); ducts: simple cuboidal, simple columnar, stratified columnar

Function: Mucous and serous secretion

Location: Sublingual and Submandibular salivary glands

Question 35

Endocrine gland: Unicelluar

Answer 35

Structure: Single cells often with glandular epithleia, subnuclear secretory vesicles released into underlying connective tissue

Function: release of hormons affecting the epithelium they reside in

Location: Scattered throuhgout GI tract

Question 36

Endocrine gland: cord

Answer 36

Structure: Plates of polygonal cells supported by reticular tissue and surrounded by abundant capillaries

Function: release of various hormones

Location:pituitary, parathyroid, and adrenal glands; islets of langerthans

Question 37

Endocrine gland: follicles

Answer 37

Structure: Spherical secretory units lined by simple cuboidal endocrine cells filled with gelatinous colloid

Function: Storage of iodide, production and secretion of thyroid hormones

Location:Thyroid gland