Epithelial Tissue

Question 1

Endothelium

Answer 1

Simple stratified; lines blood vessels

Question 2

Endothelium

Answer 2

Simple squamous; lines ventricles of the heart

Question 3

Mesothelium

Answer 3

Simple stratified; lines the body cavities (peritoneal, pericardial, pleural)

Question 4

Endothelium

Answer 4

Simple squamous; lines ventricles of the heart

Question 5

Mesothelium

Answer 5

Simple squamous; lines the body cavities (peritoneal, pericardial, pleural)

Question 6

Transitional epithelium - location, structure, and functions

Answer 6

AKA Urothelium

Question 7

Transitional epithelium - location, layering(?), and key feature

Answer 7

AKA Urothelium

Located lining the lower urinary tract

Structure: stratified

Key feature: special morphology with distensible properties

Question 8

Pseudostratitfied epithelium

Answer 8

Appears stratified b/c some cells do not reach the free surface, but ALL cells rest on the basement membrane (which is why it is considered simple)

Question 9

What key feature does an epithelial lining have to have to be considered “simple?”

Answer 9

ALL cells must be in contact/resting on the basement membrane

Question 10

Tarsal (Meibomian) glands

Answer 10

In eyelid; use holocrine secretion to expel lubricating substance onto the surface of the eye

Question 11

State the main 3 functions of the epithelium

Answer 11

Protection, absorption, secretion

Question 12

Name the five types of apical specialization

Answer 12

Ciliated, microvilli, stereociliated, keratinized, and secretory (lots of sub-types)

Question 13

Basal lamina - location, composition, functions

Answer 13

Part of the basement membrane that is closest to the epithelial layer.

Contains type IV collagen and laminin (large glycoproteins that bind with integrin proteins in the basal cell membrane of epithelia

Functions: scaffolding, filtration

Question 14

Laminin

Answer 14

Large glycoproteins in the basal lamina that bind to integrin proteins on basal side of the epithelial cells

Question 15

Reticular lamina - location, composition, and functions

Answer 15

Layer of basement membrane that is closest to the connective tissue layer

Composed of type III collagen

Main function: anchoring the BM to the connective tissue

Question 16

Zonula Occludens - common name, function, major transmembrane link proteins, and cytoskeleton components

Answer 16

Tight Junction

Functions: SEALS adjacent cells together; separates apical and basolateral membrane domains;

Transmembrane proteins: occludins, claudins, ZO proteins

Cytoskeleton: actin filaments

Question 17

Name the essential cell junction in the fetal blood-brain barrier

Answer 17

Zonula occludens (tight junctions) - defects in occludin proteins in the fetal BBB can cause severe neuro defects

Question 18

Zonula Adherens

Answer 18

Adherens Junctions

Function: strengthens and stabilizes nearby tight junctions by linking neighboring cells’ cytoskeletons

Transmembrane proteins: E-cadherins, catenin complexes

Cytoskeleton comp: actin

Question 19

Macula Adherens

Answer 19

Desmosomes

Function: strengthening tissues via strong intermediate filaments coupling between neighboring cells

Transmembrane link proteins: Desmogleins, desmocolin (parts of the Cadherin family of proteins)

Cytoskeleton components: intermediate filaments, including desmoplakin