Topic 7: Tissue Level of Organization - Epithelial Tissue

Question 1

What is epithelial tissue? AKA where would you find it (2)

Answer 1

• covers body surface (skin)
• lines body/ organs cavities

Question 2

What are organ cavities generally called?

Answer 2

lumen

Question 3

What are the characteristics of epithelial tissue? (4)

Answer 3

• has one free surface (what you are protecting the organ from)
• little extracellular space between cells
• avascular (no blood vessels)
• Basement membrane

Question 4

What are the characteristics of a basement membrane? (2)

Answer 4

• extracellular layer (not inside cell)
• attaches epithelium to underlying CT layer (formed by both tissues = “velcro”)
• blistering is an example

Question 5

How is epithelial tissue classified and named? (2)

Answer 5

• according to the number of cell layers sitting on the basement membrane
• shape of the cells in the apical layer

Question 6

What is the apical layer?

Answer 6

• layer touching the free surface

Question 7

How would you classify epithelial tissue with:
1) one layer
2) more than one layer
of cell layers sitting on the basement membrane?

Answer 7

one layer = simple
more than one layer = stratified

Question 8

How would you classify epithelial tissue with the shape of cells in the apical layer being:
1) flattened
2) cube/round
3) rectangular

Answer 8

1) flattened = squamous
2) cube/round = cuboidal
3) rectangular = columnar

Question 9

What does the simple epithelia (1 layer) allow for?

Answer 9

• allow exchange of molecules (gasses, nutrients, etc.) for absorption/secretion

Question 10

What is simple squamous epithelia? Give an example

Answer 10

1 layer of squished (flat) cells
ex. lungs

Question 11

What is simple cuboidal epithelia? Give an example.

Answer 11

1 layer of cube shaped cells
ex. kidneys

Question 12

What is simple columnar epithelia? Give an example

Answer 12

• 1 layer of column shaped (tall and thin) cells
  ex. stomach, small intestine

Question 13

What is stratified squamous epithelia? Give an example and how often you can find it

Answer 13

• apical cells squished (flat)
• common
• ex. skin

Question 14

What is stratified cuboidal epithelia? Give an example and how often you can find it

Answer 14

• apical cells cube shaped
• rare
  ex. duct of salivary gland

Question 15

What is stratified columnar epithelia? Give an example and how often you can find it

Answer 15

• apical cells column shaped (tall and thin)
• Rare
  Ex. lining of the urethra

Question 16

What is pseudostratified epithelia?

Answer 16

• appears stratified (nuclei at different levels; not all cells reach apical surface) but all cells sit on basement membrane (= simple!)

Question 17

Where in the body can you find pseudostratified epithelia?

Answer 17

• lines most of the respiratory tract and is ciliated

Question 18

What is transitional epithelia? (3)

Answer 18

• cell shape (and layering) varies with stretching
• only found in inner lining of urinary system
• goes from cuboidal to squamous when stretched
  ex. bladder

Question 19

What is glandular epithelium?

Answer 19

• if the epithelia cells form a gland, the cell layer(s)/cell shape classification is no longer used, and tissue is classified as this

Question 20

What is the purpose of glandular epithelium?

Answer 20

for secretion

Question 21

What are two examples of glandular epithelium?

Answer 21

• exocrine glands
• endocrine glands

Question 22

What are exocrine glands? (2)

Answer 22

• secrete products onto body surface or into a body cavity
• can be unicellular or multicellular

Question 23

What are unicellular exocrine glands? (3)

Answer 23

• ex. goblet cells
• secrete mucus (into a cavity)
• found in the digestive, urinary, reproductive, and respiratory tract

Question 24

What are multicellular exocrine glands? (2)

Answer 24

• consists of secretory and duct cells (ducts connect secretions to surface or cavity)
• ex. glands: sodoriferous (sweat), sebaceous (oil), mammary, difestive

Question 25

What are endocrine glands?

Answer 25

• no ducts (ductless)
• secretes hormones that will circulate in the blood
  ex. thyroid gland secretes thyroid hormone

Question 26

What are the functions of epithelia?

Answer 26

1. Protection
2. Secretion
3. Control of Permeability

Question 27

What type of epithelia would be used for protection?

Answer 27

• often stratified squamous
  ex. epidermis of skin

Question 28

What type of epithelia would be used for secretion?

Answer 28

• glandular epithelium
  ex. thyroid, sweat glands