4.4 The Tissue Level Of Organization: Epithelial Tissue

Front 1

What is epithelial tissue?

Back 1

The tissue that forms the innermost and outermost surfaces of body structures and forms glands. Also called epithelium.

Front 2

What are the 3 major function of epithelial tissue?

Back 2

(1) a selective barrier that limits or aids the transfer of substances into and out of the body; (2) a secretory surface that releases products produced by the cells onto its free surfaces; and (3) a protective surface that resists the abrasive influences of the environment.

Front 3

The apical (free) surface faces what?

Back 3

Faces the body surface, a body cavity, the lumen (interior space) of an internal organ, or a tubular duct that receives cell secretions.

Front 4

Apical surfaces may contain what?

Back 4

cilia or microvilli

Front 5

The lateral surfaces of an epithelial cell faces what?

Back 5

face the adjacent cells on either side

Front 6

The lateral surface may contain what kind of junctions?

Back 6

Tight junctions, adherens junctions, desmosomes, and/or gap junctions.

Front 7

The basal surface of an epithelial cell is opposite of what?

Back 7

The apical surface.

Front 8

The basal surface adheres to what?

Back 8

Adhere to extracellular materials such as the basement membrane.

Front 9

What are the functions of the basement membrane?

Back 9

The basement membrane provides physical support for the epithelial tissue and plays a part in growth and wound healing, restriction of molecular movement between tissues, and blood filtration in the kidneys.

Front 10

The basal lamina is secreted by what? It contains what?

Back 10

Secreted by epithelial cells. It contains proteins such as laminin and collagen, as well as glycoproteins and proteoglycans.

Front 11

The reticular lamina is closer to what? It contains what?

Back 11

Closer to the underlying connective tissue and contains proteins such as collagen produced by connective tissue cells called fibroblasts.

Front 12

Epithelial tissue may be divided into two types. What are they?

Back 12

(1) Covering and lining epithelium

(2) Glandular epithelium

Front 13

Types of covering and lining epithelial tissue are classified according to two characteristics. What are they?

Back 13

The arrangement of cells into layers and the shapes of the cells.

Front 14

What are the possible arrangements of cells into layers? Briefly define.

Back 14

Simple epithelium: single layer of cells (functions in diffusion, osmosis, filtration, secretion, or absorption)

Pseudostratified epithelium: appears to have multiple layers of cells; actually a simple epithelium

Stratified epithelium: 2 or more layers protect underlying tissues

Front 15

What are the possible cell shapes? Briefly define.

Back 15

Squamous cells: thin

Cuboidal cells: cubes or hexagons, may have microvilli

Columnar cells: like columns, may have microvilli or cilia

Transitional cells change shape, from squamous to cuboidal and back in organs that stretch and collapse

Front 16

What type of arrangement of layers is this?

Back 16

Simple

Front 17

What type of arrangement of layers is this?

Back 17

Pseudostratified

Front 18

What type of arrangement of layers is this?

Back 18

Stratified

Front 19

What type of cell shape is this?

Back 19

Squamous

Front 20

What type of cell shape is this?

Back 20

Cuboidal

Front 21

What type of cell shape is this?

Back 21

Columnar

Front 22

Which cell shape is best adapted for the rapid movement of substances from one cell to another?

Back 22

Because the cells are so thin, substances move most rapidly through squamous cells.

Front 23

What type of tissue is this?

Back 23

Simple Squamous Epithelium

Front 24

Where do you find simple squamous epithelium?

Back 24

Most commonly (1) lines the cardiovascular and lymphatic system (heart, blood vessels, lymphatic vessel linings, called endothelium)

(2) forms the epithelial layer of serous membranes (peritoneum, pleura, pericardium), where it is called mesothelium. Also found in air sacs of lungs, glomerular (Bowman's) capsule of kidneys, inner surface of tympanic membrane.

Front 25

What is the function of simple squamous epithelium?

Back 25

Present at sites of filtration, diffusion, secretion. Not found in body areas subject to mechanical stress (wear and tear).

Front 26

What type of tissue is this?

Back 26

Simple Cuboidal Epithelium

Front 27

Where would you find simple cuboidal epithelium?

Back 27

Ovary, lens of the eye, retina of the eye, kidney tubules, secreting portion of thyroid gland and ducts of some glands such as pancreas.

Front 28

What are the functions of simple cuboidal epithelium?

Back 28

Secretion and absorption.

Front 29

What type of tissue is this?

Back 29

Nonciliated simple columnar epithelium

Front 30

Where would you find nonciliated simple columnar epithelium?

Back 30

Lines gastrointestinal tract (from stomach to anus), ducts of many glands, and gallbladder.

Front 31

What are the functions of nonciliated simple columnar epithelium?

Back 31

Secretion and absorption

Front 32

What type of tissue is this?

Back 32

ciliated simple columnar epithelium

Front 33

Where would you find ciliated simple columnar epithelium?

Back 33

Lines some bronchioles (small tubes) of respiratory tract, uterine (fallopian) tubes, uterus, some paranasal sinuses, central canal of spinal cord, and ventricles of brain.

Front 34

What are the functions of ciliated simple columnar epithelium?

Back 34

Moving mucus and foreign particles, move oocytes expelled from ovaries through uterine (fallopian) tubes into uterus..

Front 35

What type os tissue is this?

Back 35

pseudostratified columnar epithelium

Front 36

Where would you find pseudostratified columnar epithelium?

Back 36

Ciliated variety lines airways of most of upper respiratory tract; nonciliated variety lines larger ducts of many glands, epididymis, and part of male urethra.

Front 37

What are the functions of pseudostratified columnar epithelium?

Back 37

Ciliated variety secretes mucus that traps foreign particles, and cilia sweep away mucus for elimination from body; nonciliated variety functions in absorption and protection.

Front 38

What type of tissue is this?

Back 38

stratified squamous epithelium

Front 39

Where would you find stratified squamous epithelium?

Back 39

Keratinized variety forms superficial layer of skin; nonkeratinized variety lines wet surfaces (lining of mouth, esophagus, part of epiglottis, part of pharynx, and vagina) and covers tongue.

Front 40

What are the functions of stratified squamous epithelium?

Back 40

Protection against abrasion, water loss, ultraviolet radiation, and foreign invasion. Both types form first line of defense against microbes.

Front 41

What type of tissue is this?

Back 41

stratified cuboidal epithelium

Front 42

Where would you find stratified cuboidal epithelium?

Back 42

Ducts of adult sweat glands and esophageal glands, part of male urethra.

Front 43

What are the functions of stratified cuboidal epithelium?

Back 43

Protection; limited secretion and absorption.

Front 44

What type of tissue is this?

Back 44

stratified columnar epithelium

Front 45

Where would you find stratified columnar epithelium?

Back 45

Lines part of urethra; large excretory ducts of some glands, such as esophageal glands; small areas in anal mucous membrane; part of conjunctiva of eye.

Front 46

What are the functions of stratified columnar epithelium?

Back 46

Protection and secretion.

Front 47

What type of tissue is this?

Back 47

transitional epithelium

Front 48

Where would you find transitional epithelium?

Back 48

Lines urinary bladder and portions of ureters and urethra.

Front 49

What are the functions of transitional epithelium?

Back 49

Allows urinary organs to stretch and maintain protective lining while holding variable amounts of fluid without rupturing.

Front 50

What is an endocrine gland?

Back 50

A gland that secretes hormones into interstitial fluid and then the blood; a ductless gland.

Front 51

What is an exocrine gland?

Back 51

A gland that secretes its products into ducts that carry the secretions into body cavities, into the lumen of an organ, or to the outer surface of the body.

Front 52

What are unicellular glands? Multicellular glands? Simple glands? Compound glands? Tubular glands? Acinar glands? Tubuloacinar glands?

Back 52

Unicellular: single-celled

Multicellular: multi-celled

Simple: duct does not branch

Compound: duct branches

Tubular: tubular secretory part

Acinar: rounded secretory part

Tubuloacinar: tubular and rounded secretory parts

Front 53

How do simple multicellular exocrine glands differ from compound ones?

Back 53

Simple multicellular exocrine glands have a nonbranched duct; compound multicellular exocrine glands have a branched duct.

Front 54

What kind of secretion is this?

Back 54

Merocrine secretion

Front 55

What is a merocrine gland?

Back 55

Gland made up of secretory cells that remain intact throughout the process of formation and discharge of the secretory product, as in the salivary and pancreatic glands.

Front 56

What kind of secretion is this?

Back 56

Apocrine secretion

Front 57

What is an apocrine gland?

Back 57

A type of gland in which the secretory products gather at the free end of the secreting cell and are pinched off, along with some of the cytoplasm, to become the secretion, as in mammary glands.

Front 58

What kind of secretion is this?

Back 58

Holocrine secretion

Front 59

What is a holocrine gland?

Back 59

A type of gland in which entire secretory cells, along with their accumulated secretions, make up the secretory product of the gland, as in the sebaceous (oil) glands.

Front 60

To what class of glands do sebaceous (oil) glands belong? Salivary glands?

Back 60

Sebaceous (oil) glands are holocrine glands, and salivary glands are merocrine glands.