510-5 Epithelia

Question 1

Epithelia is sensitive and doesn’t bleed. How do we describe this?

Answer 1

Highly innervated and Avascular

Question 2

What are the two general layers of the basement membrane?

Answer 2

The Basal Lamina and the Reticular Lamina

Question 3

What type of collagen is found in basal lamina and what are its properties?

Answer 3

Type IV Collagen

a loose, gel-like collagen

Question 4

What are the two layers of Basal Lamina?

Answer 4

Lamina Lucida

Lamina Densa

Question 5

Where is Laminin found and what does it do?

Answer 5

Found in the Lamina Lucida

It’s a glycoprotein that binds the type IV collagen in the Lamina Densa

Question 6

What is the Lamina Densa largely compose of?

Answer 6

Type IV collagen

Question 7

How are the Basal Lamina and Reticular Lamina joined together?

Answer 7

Loops of type VII Collagen anchoring fibrils.

Question 8

Name the 3 types of Collagen found in the basement membrane.

Answer 8

Type I - Largest fibrils found deepest in Reticular Lamina
Type VII - loops found in the Reticular lamina anchoring into the Lamina Densa of the Basal Lamina.
Type IV - gel like collagen found in the Lamina Densa portion of the Basal Lamina

Question 9

Drawn correctly, is Transitional Epithelium (as in the lining of the bladder) Stratified or Psuedo-stratified?

Answer 9

Psuedo Stratified

Question 10

What’s the advantage to a simple squamous epithelium?

Answer 10

Rapid Diffusion

Question 11

What might staggering of cell nuclei in columnar epithelium suggest?

Answer 11

pseudo-stratification

found in upper respiratory tract (trachea, nasal cavities)

Question 12

What are the 3 layers of a mucous membrane?

Answer 12

Epithelial Cells
Lamina Propria    (vascular connective tissue)
Musculara Mucosae (thin layer of smooth muscle)

Question 13

Name a difference between non-keratinized and keratinized epithelium.

Answer 13

Nucleated (non-keratinized)

Non-nucleated (keratinized)

Question 14

Where is non-keratinized, stratified, squamous epithelium found?

Answer 14

Oral mucosa, esophagus, vagina

Question 15

Where do you find keratinized stratified squamous epithelium?

Answer 15

Skin

some Oral Epithelia

Question 16

Where do you find stratified cuboidal and stratified columnar epithelia?

Answer 16

Certain ducts (pancreas, salivary, sweat glands - uncommon)

Question 17

Where would you find Domed surface epithelium with protein plaques on the free surface?

Answer 17

Bladder.
Pseudostratified transitional epithelium

look for: pseudostratified, dark plaques on free surface

Question 18

What’s the only cell that lacks an intercellular junction?

Answer 18

Erythrocytes (red blood cells)

Question 19

What is the function of a tight junction?

Answer 19

Waterproofing
think caulking / magnets zipping up toward the apical end

AKA - Zona Occludens

Question 20

What is the function of an adhesive junction?

What role does Ca++ play?

Answer 20

Cell binding
think velcro or glue (uses actin filaments)
AKA - Zona Adherens
Ca++ allows binding of actin. Kelating inhibits Calcium from doing this

Question 21

What is the function of a Desmosome?

Answer 21

Very tight junction

think bolts (joins intermediate filaments)

Hold cells together against mechanical stresses

Question 22

What is the function of a hemi-desmosome?

Answer 22

Connects the cell to underlying connective tissue via intermediate filaments (in the cell), various collagen and proteins, and ultimately to the type VII collagen loops in the Reticular Lamina

Question 23

How many connexin = one connexon

Answer 23

Six

Question 24

What is a primary structural difference between exocrine and endocrine glands?

Answer 24

Exocrine glands have ducts, Endocrine glands don’t

Question 25

Name two mixed (endocrine/exocrine) glands.

Answer 25

Pancreas (endocrine hormones without ducts, exocrine products via ducts)
Liver

Question 26

Two structural types of exocrine glands

Answer 26

Simple and Compound (branched)

Question 27

Describe a tubuloacinar gland.

Answer 27

A compound gland with secretory cells at both bulged acinar regions AND throughout duct (tubed) regions.
I.e. Breast ducts

Question 28

What kind of gland releases whole cells into ducts?

Answer 28

Cytogenetic glands

Question 29

What is the mechanism of merocrine secretion?

Answer 29

Exocytosis at the apical end of the cell.
(Releases into a duct)
(Most common type of secretion)

Question 30

Sebaceous glands secrete by what process?

Answer 30

Holocrine

The cell swells then lyses, releasing contents.

Question 31

Name two surfaces of epithelia.

Answer 31

Basal surface and free surface