A & P - Epithelial Tissue

Front 1

What is the etymology of "epithelium"?

Back 1

Greek, above the nipple (thel = teat)

Front 2

What is epithelial tissue?

Back 2

Tissue that forms the innermost and outermost surfaces of body structures (coverings and linings) and forms glands

In other words, surface tissue or glandular tissue.

Front 3

What are 3 main functions of epithelial tissue?

Back 3

1) Selective barriers between distinct compartments of the body

2) Secretory surfaces that release products produced by cells onto their free surfaces

3) Protective surfaces that resist the abrasive properties of the environment

Front 4

What are the different sides of epithelial cells called?

Back 4

Apical (free) surface - faces the body surface or cavity, or duct

Lateral surface - Face adjacent cells on either side

Basal surface - Opposite the apical surface

Front 5

What is the basement membrane of an epithelium?

Back 5

Thin extracellular layer that adheres to the basal surface of epithelial cells

Commonly consists of two layers: basal lamina (adheres to cell) and reticular lamina (further from epithelial cells)

Front 6

What are the distinctive properties of epithelial tissue?

Back 6

1) Avascular
2) Always has a free surface
3) Sits on an extracellular basement membrane

Front 7

Is epithelial cell division rapid or slow?

Back 7

Rapid because of the physical stress and injury that it is repeatedly subjected to

Front 8

What are the two types of epithelial tissue?

Back 8

1) Covering and lining epithelium - forms outer and inner linings of body

2) Glandular epithelium - makes up secreting portion of glands such as the thyroid gland, adrenal glands, and sweat gland

Front 9

By which 2 properties are subtypes of covering/lining epithelium classified?

Back 9

1) Arrangement of cells in layers (simple, pseudostratified, stratified)

2) Cell shapes (squamous, cuboidal, columnar, transitional)

Front 10

Name the 3 ways in which the cells of covering/lining epithelium are arranged:

Back 10

1) Simple epithelium
2) Pseudostratified epithelium
3) Stratified epithelium

Front 11

What is simple epithelium?

Back 11

Single layer of epithelium in which all cells sit on basement membrane and all cell nuclei are at approximately the same level

Front 12

What is pseudostratified epithelium?

Back 12

Simple epithelium that appears to have multiple layers because the cell nuclei lie at different levels and not all cells reach the apical surface

Still a single layer of cells with each cell attached to the basement membrane (simple epithelium)

Cells reaching apical surface may have cilia or be mucous secreting goblet cells)

Front 13

What is stratified epithelium?

Back 13

Epithelium consisting of 2 or more cell layers with only the bottom layer attached to basement membrane

Front 14

What are the 4 different cell shapes of epithelial tissue?

Back 14

1) Squamous
2) Cuboidal
3) Columnar
4) Transitional

Front 15

Describe the shape of squamous epithelial cells:

Back 15

Thin, flat cells arranged like floor tiles

Like scales

Front 16

Describe the shape and features of cuboidal epithelial cells:

Back 16

Tall as they are wide, shaped like cubes or hexagons

May have microvilli at surface

Front 17

Describe the shape and features of columnar epithelial cells:

Back 17

Much taller than they are wide

May have cilia or microvilli

Front 18

What are transitional epithelial cells?

Back 18

Epithelial cells that change shape from flat to cuboidal and back as organs such as the urinary bladder stretch to a larger size and then collapse to a smaller one