Chapter 4: Epithelial Tissue

Front 1

Epithelial Tissue

Back 1

- covers or lines every body surface and all body cavities

Front 2

Characteristics of Epithelial Tissue

Back 2

- composed entirely of cells

- polarity: ezposed to external surface or interanl body cavity

- the basal surface of epithelial tissue is bound to a thin basement membrane

- avasculairty: lack blood vessels obrains nutrients directly acroos apical sufcae of by difussion thorugh basal layer

- richly innervated

- highly regerneration capacity

Front 3

Functions

Back 3

- physical proteciton

- Selecive permeability

- secretion

- sensations

Front 4

Basement Membrane

Back 4

- three layer between epithelial and connective tissue

- two laminae: closest to epithelium contain collagen fibers

recticular lamina: cells underlying connective tissue

Front 5

Basement Membrane Functions

Back 5

- Physical support for epithelium

- anchoring epithelium to connective tissue

- barrier that regulates moelcule between epithelium and connective tissue

Front 6

Intercellular Junctions

Back 6

- specialized connections in the plasma membrane of their lateral surfaces

- four types of junctions

Front 7

Tight Junctions

Back 7

- encircles epithelial cells near their apical surface and compleltely attaches eahc cell together

Front 8

Adhering Junctions

Back 8

- formed completely around the cell type of support for the cell provides the only means of junctional support for the aprical surface

Front 9

Desmososes

Back 9

- a button or snap between adjacent epithelial cells

- holds cells together only at stress points

Front 10

Gap Junctions

Back 10

- across intercellular hap between neighbor cells

Front 11

Simple Epithelium

Back 11

one cell layer thick and in direct contact with basement cell

- apical surface is often covered by mucus to prevent form friction

- found where primary function is filtration, absorption, or secretion

Front 12

Stratified Epithelium

Back 12

- two or more layers of epithelium cells

- found where areas are subjected to stress or abrasive actvities

Front 13

Squamos Cells

Back 13

- are flat, wide, irregular in shape

- nuclesu is flattened disk

Front 14

Cubodial Cells

Back 14

- tall as they are wide

- nucleus is oval

- located in bassal layer region

Front 15

Transitional Cells

Back 15

- change thier shape depending how stretched epithelial tissue becomes

Front 16

Simple squamos epithelial

Back 16

- single layer of flattened cells

- extremely delicated and highly specialized to allwo rapid movement of moelcules across the surface

- only found in protected regions where moist surfaces reduce friction

Front 17

Simple Cubodial Epithelium

Back 17

- fucntions pirmarily to absorb fluids and other subtances across apical membrane

Front 18

Simple Columnar Epithelium

Back 18

- has two forms with cilia and with out

- noncilitated: absorption and secretion of mucin

- Ciliated: Mucus covers the surface, secretion of msucin by action of cilia

Front 19

Stratified Squamos Epithelium

Back 19

- exists in two forms: nonkeratinized and keratinized

- nonkeratinized: remian alive all the way to apical suface and kept moist

Keratinized: apical surface is composed of cells that are dead/lack nucei and/or organelles

Front 20

Stratified Cubodial Epithelium

Back 20

- function is mainly protective, its strengthens wall of gland ducts

Front 21

Stratified Columnar Epithelium

Back 21

- found in large ducts of salivary glands

Front 22

Pseudostrafied Columnar Epithelium

Back 22

- found in two forms: ciliated and nonciliated

- ciliated: secrete mucins

- nonciliated: no goblet cells

Front 23

Transitional Epithelium

Back 23

- handful presense of binucleated cells

Front 24

Glands

Back 24

- individual cells or mulitcellular organs compsoed mostly of epithelial cells

Front 25

Endocrine Cells

Back 25

- secrete products directly into the blood stream

Front 26

Exocrine Glands

Back 26

- maintain contact with epithelial surface by meand of a duct

Front 27

Simple Gland

Back 27

- have single branched ducts

Front 28

Compound Glands

Back 28

- exhbit branched ducts

Front 29

Serous Glands

Back 29

- produce watery fluid like sweat, milk, tears

Front 30

Muccus Glands

Back 30

- secret mucin which forms mucus when mixed with water

Front 31

Mixed Gland

Back 31

- contain both serous and mucous cells

Front 32

Merocrine Glands

Back 32

- package secertion in secretory vesciles and travel to apical surface and release by exocytosis

Front 33

Holocrine Glands

Back 33

- cell accumulates a product then disintegrats

Front 34

Aprocrine Glands

Back 34

- cells acculate thier secreoty product within apical proitonof thier cytoplasm