Epithelial Tissue

Question 1

Avascular tissue is composed of cells that: (4)

Answer 1

o cover the exterior body surfaces
o line the internal closed cavities including the vascular system
o line body tubes that communicate with the exterior (GIT, urogenital and respiratory tracts)
o form secretory portions and ducts of glands

Question 2

What are the defining characteristics of epithelial tissue?

Answer 2

1. Cells are in close apposition and have little extracellular matrix
2. Functional and morphologic polarity
   o Cells have 3 domains- apical domain, lateral domain and basal domain
3. Cells adhere strongly by specialized cell junctions
4. Cell basal surface attaches to basement membrane

Question 3

What is epithelioid tissue? (2)

Answer 3

o Cells that are closely apposed and have a basement membrane but lack a free surface
o Present as most endocrine glands

Question 4

How does epithelium function as a selective barrier?

Answer 4

Epithelia covering and lining surfaces form a sheet-like cellular investment that separates underlying connective tissue from the external environment, internal cavities or fluid connective tissue (blood or lymph)

Question 5

What are the functions of epithelia? (5)

Answer 5

Question 6

How does the classification of epithelial tissue take place?

Answer 6

Question 7

Simple squamous:
Image
Locations
Functions

Answer 7

Question 8

Simple cuboidal:
Image
Locations
Functions

Answer 8

Question 9

Simple columnar:
Image
Locations
Functions

Answer 9

Question 10

Pseudostratified columnar:
Image
Locations
Functions

Answer 10

Question 11

Stratified squamous:
Image
Locations
Functions

Answer 11

Question 12

Stratified cuboidal:
Image
Locations
Functions

Answer 12

Question 13

Transitional (urothelium):
Image
Locations
Functions

Answer 13

Question 14

• Epithelia may also be classified according to its _____ specialisations if present
• Some exocrine glands have cells that are _____ in shape
• These cells are still classified as either columnar or cuboidal

Answer 14

apical
pyramidal

Question 15

In stratified epithelium:
o The cell ____ and ____ vary from layer to layer
o Only the shape of the cells that form the surface layer is used in classification.

Answer 15

height
shape

Question 16

What are the SPECIAL classifications of epithelia? (2)

Answer 16

1. Pseudostratified epithelium
   o Nuclei are at different levels and some cells do not reach the free surface
   o Since all cells rest on the basement membrane, it is regarded as a simple epithelium
2. Transitional epithelium (urothelium)
   o Stratified epithelium with special

Question 17

Simple squamous epithelia in specific locations:
1. Endothelium-
2. Endocardium-
3. Mesothelium-

Answer 17

lining of the blood and lymphatic vessels

lining of the ventricles and atria of the heart

lining of the walls of the abdominal, pericardial and pleural cavities

Question 18

• Specific _____ characteristics are associated with each cell surface
• The free apical domain is always directed toward the exterior surface of the lumen of an enclosed cavity or tube
• The lateral domain ________ with adjacent cells and has specialised attachment areas
• The basal domain rests on the ______ _____ anchoring the cell to underlying connective tissue

Answer 18

biochemical
communicates
basal lamina

Question 19

What are the Apical Domain Specializations? (3)

Answer 19

1. Microvilli
2. Stereocilia (stereovilli)
3. Cilia

Question 20

What are microvilli? (5)

Answer 20

• Cytoplasmic processes containing a core of actin filaments
• Functions in increasing surface area for absorption
• In kidney tubules- brush border
• In GIT- striated border
• Also located in brain ependyma

Question 21

What are Stereocilia (stereovilli)? (3)

Answer 21

• Microvilli of unusual length (very long)
• Functions in facilitating absorption and mechanoreception
• Limited to male reproductive system and sensory hair cells in the ear

Question 22

What are cilia? (4)

Answer 22

• Motile cytoplasmic processes
• Contains the motor protein dynein
• Core of microtubules in 9+2 pattern
• Functions in transportation

Question 23

Where are cilia found? (4)

Answer 23

o Oviducts
o Trachea and bronchi
o Brain ependyma
o Olfactory epithelium

Question 24

Zonula Occludens (tight junction):
Image
Cytoskeleton Component
Functions

Answer 24

Question 25

Zonula Adherens: Image Cytoskeleton Component Functions

Answer 25

Question 26

Macula Adherens (desmosome): Image Cytoskeleton Component Functions

Answer 26

Question 27

Focal adhesions vs Hemidesmosomes Image Cytoskeleton Component Functions

Answer 27

Question 28

Gap junction (nexus) Image Cytoskeleton Component Functions

Answer 28

Question 29

True or false Basement membrane * Visible on light microscope with Periodic Acid-Schiff staining technique as magenta

Answer 29

True

Question 30

What is the structure and composition of the basal lamina? (2)

Answer 30

o Structural attachment site for overlying epithelial cells and underlying connective tissue o Composed of laminins, type IV collagen, proteoglycans and glycoproteins

Question 31

What is the function of basal cell membrane infoldings? (4)

Answer 31

* Increase surface area of basal domain * Allows for more transport proteins and channels to be present * Prominent in cells that participate in active transport of molecules (kidney tubules and salivary glands) * Orientation of mitochondria together with infoldings results in striated appearance

Question 32

What are the staining techniques?

Answer 32

Question 33

What are the types of Glandular Epithelium?

Answer 33

Question 34

Classification by mode of secretion: (3)

Answer 34

1. Merocrine secretion 2. Apocrine secretion 3. Holocrine secretion

Question 35

What is Merocrine secretion? (4)

Answer 35

* Delivered in membrane-bound vesicles to the apical surface * Vesicles fuse with cell membrane * Contents are extruded via exocytosis * Most common mode of secretion

Question 36

What is Apocrine secretion? (3)

Answer 36

* Product is release in apical portion of the cell * A thin layer of cytoplasm within an envelope of cell membrane pinches off from the cell * Found in lactating mammary gland and armpit and groin area

Question 37

What is Holocrine secretion? (4)

Answer 37

* Product accumulates within the maturing cell * The cell undergoes apoptosis and lyses * Product and cell debris is released into the lumen of the gland * Found in sebaceous glands and tarsal (Meibomian) glands of the eyelid

Question 38

What are the types of simple glands?

Answer 38

Question 39

What are the types of compound glands?

Answer 39

Question 40

Simple tubular gland: Image Typical Location Features

Answer 40

Question 41

Simple coiled tubular gland: Image Typical Location Features

Answer 41

Question 42

Simple branched tubular gland: Image Typical Location Features

Answer 42

Question 43

Simple alveolar gland: Image Typical Location Features

Answer 43

Question 44

Simple branched alveolar gland: Image Typical Location Features

Answer 44

Question 45

Compound tubular gland: Image Typical Location Features

Answer 45

Question 46

Compound alveolar gland: Image Typical Location Features

Answer 46

Question 47

Compound tubulo-alveolar gland: Image Typical Location Features

Answer 47

Question 48

What is mucus secretion? (6)

Answer 48

Question 49

What is serous secretion? (5)

Answer 49

Question 50

Where is Mucoserous found?

Answer 50

Found in submandibular (tubule-alveolar) glands

Question 51

What are Myoepithelial cells? (6)

Answer 51

* Contractile * Have actin filaments * Surround SEPs * Located in between basement membrane and basal part of secretory cells * Have a squashed appearance * Stain darkly