Ch 4: Epithelium & Connective Tissues

Question 1

Papillae

Answer 1

Small evaginations that serve as irregularities between the epithelium and connective tissue.

They serve where tissue is subject to friction.

Question 2

Do epitheail cells show Polarity?

Answer 2

Yes

Question 3

What does the lamina propria do?

Answer 3

The connective tissue that underlies the
epithelia lining of the organs of the digestive, respiratory, and
urinary systems.

Question 4

the opposite end, usually facing a space,
is the….

Answer 4

Apical Pole

Question 5

Regions of cuboidal or columnar cells
that adjoin the neighboring cells are called

Answer 5

The Lateral Surfaces.

cell membranes here often have numerous infoldings to increase
the area of that surface, increasing its functional capacity.

Question 6

All epithelial cells in contact with subjacent connective tissue
have at their basal surfaces a specialized, feltlike sheet of extracellularmaterial referred to as….

Answer 6

basement membrane

Question 7

Nearest the epithelial basal poles is an electron-dense layer,
20-100 nm thick, consisting of a network of fine fibrils that
comprise

Answer 7

The Basal Lamina:

This lamina is made up of fine fibrils near the epithelial basal pole

Question 8

reticular lamina

Answer 8

Lies Beneath the Basal lamina and is a more diffuse and fibrous.

Question 9

The 3 parts that make up the Basal Lamina are?

Answer 9

Laminin: These are large glycoproteins that self-assemble
as a lacelike network immediately below the cells’ basal
poles where they are held in place by the transmembrane
integrins.
■■ Type IV collagen: Monomers of type IV collagen contain
three polypeptide chains and self-assemble further
to form a feltlike layer.
■■ The laminin and type IV collagen networks are held
together by the adhesive glycoprotein entactin/
nidogen, and by perlecan, a proteoglycan.

Question 10

lateral surfaces of epithelial cells exhibit several specialized
intercellular junctions, which serve different functions

The 3 are:

Answer 10

Tight or occluding junctions form a seal between
adjacent cells.
■■ Adherent or anchoring junctions are sites of string cell
adhesion.
■■ Gap junctions are channels for communication
between adjacent cells.

Question 11

The seal between the membranes is due to
interactions between the transmembrane proteins known as?

Answer 11

claudin
and occludin of each cell.

Question 12

Review the joint complexes of epithelial cells:

Answer 12

Question 13

Most cuboidal or columnar epithelial cells have four major
types of intercellular junctional complexes. At the apical end,

Answer 13

You have tight junctions (zonulae
occludens) and adherent junctions (zonulae adherens) are
typically close together and each forms a continuous ribbon
around the cell. Multiple ridges of the tight junction prevent
passive flow of material between the cells but are not very
strong

Question 14

Gap junctions,
each a patch of many __________in the adjacent cell membranes,
have little strength but serve as intercellular channels
for flow of molecules.

Answer 14

connexons

Question 15

Desmosomes (macula adherens)

Answer 15

Surface structure that helps with matching adjacent cells

Question 16

What bind epithelial cells to the underlying basal lamina?

Answer 16

Hemidesmosomes

Question 17

Adherent of anchoring junctions (Zonula Adherens) is done with?

Answer 17

Cell adhesion is mediated by cadherins in the presence of Ca2+.

Question 18

After Tight Junctions, you have a second kind of junction, known as Zonula Adherens, what do they do?

Answer 18

encircles the epithelial cell,
usually immediately below the zonula occludens. This is an
adherent junction, firmly anchoring a cell to its neighbors.

Question 19

What do Cadherins do?

Answer 19

They mediate cell adhesion and transmembrane
glycoproteins of each cell that interact in the presence
of Ca2+. At their cytoplasmic ends, cadherins bind catenin
that is linked via actin-binding proteins to actin filaments

Question 20

What are Maculae adherens or desmosomes?

Answer 20

are discshaped
structures at the surface of one cell that are matched
with identical structures at an adjacent cell surface

Question 21

Desmosomes (macula adherens) also contain:

Answer 21

larger members of the
cadherin family called desmoglein and desmocollin. On the
cytoplasmic side of each cell membrane, these proteins insert
into a dense attachment plaque of anchoring proteins (plakoglobin and desmoplakin) that bind intermediate filaments
rather than actin filaments.

Question 22

The gap junction proteins, called connexins do what?

Answer 22

form hexameric
complexes called connexons, each of which has a central
hydrophilic pore about 1.5 nm in diameter.

When two
cells attach, connexins in the adjacent cell membranes move
laterally and align to form connexons between the two cells
(Figure 4–4), with each junction having dozens or hundreds
of aligned connexon pairs.

Question 23

If you have Abnormal desmosome function, it causes

Answer 23

Blisters

Question 24

What are Hemidesmosomes?

Answer 24

These adhesive structures
resemble a half-desmosome ultrastructurally, but, unlike
desmosomes, they contain abundant integrins rather than
cadherins. The transmembrane integrin proteins bind the
extracellular macromolecules laminin and collagen type IV.

Question 25

If you have a Defect of hemidesmosomes…..

Answer 25

bullous pemphigoid.

Question 26

What do Microvili do and where are they located?

Answer 26

These modifications are specialized for absorption e.g. Small intestines where they appear as brush/striated border

Question 27

If you lose the small intestine brush border…..

Answer 27

You will have Celiac disease

Question 28

Stereocilia are a much less common type of apical process,
restricted to absorptive epithelial cells lining the epididymis
(Figure 4–9) and the proximal part of ductus deferens in the
male reproductive system.

What do they do??

Answer 28

Like microvilli, stereocilia increase
the cells’ surface area, facilitating absorption. More specialized
stereocilia with a motion-detecting function are important
components of inner ear sensory cells.

Question 29

What do Complexes with axonemal dyneins do?

Answer 29

bound to a microtubule in each doublet extend as “arms”
toward a microtubule of the next doublet. With energy from
adenosine triphosphate (ATP), dynein-powered sliding of
adjacent doublets relative to each other bends the **axoneme** and a rapid series of these sliding movements produces the beating motion of epithelial cilia.

Question 30

Cilia,

Answer 30

… are larger than microvilli, and have the 9+2 conformation called...axoneme, which are continuous with basal bodies, which areapical cytoplasmic structures just below the cell membrane
Basal bodies have a structure similar
to that of centrioles, with triplets of microtubules and dynamic
tubulin protofilaments forming rootlets anchoring the entire
structure to the cytoskeleton.

Question 31

Exocrine glands

Answer 31

These glands retain connection with the surface epithelium and have ducts.

Question 32

Endocrine glands

Answer 32

These glands lose connection to their original epithelium. and lack ducts. Capillaries absorb hormones from these glands

Question 33

List the differences between these glands:

Simple glands

Compound glands

Tubular secretory glands

Acinar secretory glands​

Answer 33

These glands have unbranched ducts

These glands have branched ducts

These glands are short, long or coiled

These glands are round and sac-like

Question 34

What is a Merocrine secretion

Answer 34

This secretion involves exocytosis mostly with proteins

Question 35

Describe the Holocrine secretion

Answer 35

cells undergo terminal differentiation and eventually release product and cell debris in lumen of gland.

Example: is sebaceous gland of skin involved in acne.

Question 36

Describe Apocrine secretion

Answer 36

products accumulate at cell apical end with portions extruded to release product with some cytoplasm and plasma membrane. Example includes lipid droplets in mammary gland.

Question 37

Serous exocrine glands with merocrine secretion do what?

Answer 37

secrete nonglycosylated proteins and include pancreatic acinar and salivary parotid glands

Question 38

Mucous exocrine glands with merocrine secretion do what?

Answer 38

secrete glycosylated proteins called …..Mucins

Question 39

Pseudostratified epithelium

Answer 39

lines the trachea

Question 40

Pseudostratified epithelium

Answer 40

Although truly composed of one layer, this epithelium appears otherwise

Question 41

Cilia

Answer 41

This apical surface modification is comprised of microtubules

Question 42

Holocrine

Answer 42

This type of secretion occurs in the sebaceous gland

Question 43

Transitional epithelium/ urothelium

Answer 43

This form of epithelium lines the urinary tract and contains umbrella cells

Question 44

Embryonic connective tissue is a form of

Answer 44

Wharton’s jelly or mucous connective tissue.

Question 45

Identify where the Epithelium, basment membrane, Lamina propia, and capillaries are.

Answer 45

Question 46

Products to be secreted are generally stored in the
cells within small membrane-bound vesicles called

Answer 46

secretory
granules.

Question 47

abundant in the lining
of the small intestine and respiratory tract,
which secretes lubricating mucus that aids the function of
these organs.

Answer 47

goblet cells