Week 2 Epithelium

Question 1

What are the 3 domains of epithileum?

Answer 1

Apical, lateral and basal

Question 2

Classes of epithelium?

Answer 2

Simple, cuboidal, columnar, squamous, stratified

Question 3

Pseudostratified epithelium is in what class?

Answer 3

Simple! Appears stratified bc the nucleii are far away from basal membrane but still connected (Ex: trachea)

Question 4

endothelium

Answer 4

lining of blood and lymph

Question 5

endocardium

Answer 5

lining of ventricles and atria

Question 6

mesothelium

Answer 6

lining of surfaces and closed cavitites

Question 7

urothelium

Answer 7

TRANSITIONAL EPITHELIUM. stratified. allows stretch. lining of bladder

Question 8

3 specialized structural features of apical domain?

Answer 8

microvilli, stereocilia, cilia

Question 9

Microvilli

Answer 9

actin core
transport fluid
*structure/function similar but organization different
villin and terminal web

Question 10

villin

Answer 10

localized to the tip of microvilli

barbed end biding protein

Question 11

terminal web

Answer 11

actin found at the base of microvilli that allows spectin and myosin to bind microvilli to plasma membrane

Question 12

spectin and myosin

Answer 12

proteins that attach actin microvilli to the plasma membrane

Question 13

stereocilia

Answer 13

mechano-receptors =sense movement
found in ear
NO villin protein at tip, but actin core
long, not wiidely distributed

Question 14

cilia

Answer 14

NOT actin based
microTUBULE based internal structure called axoneme connected to MTOC (made of alpha and beta tubulin)
3 types of cilia; motile, primary, nodal

Question 15

3 types of cilia

Answer 15

motile, primary, nodal

Question 16

motile cilia

Answer 16

9+2 axonemal microtubule based internal structure
found in LARGE numbers ( trachea, oviducts)
Dynein motor protein

Question 17

dynein

Answer 17

motor protein associated with motile cilia (and nodal cilia)
causes cilia to beat
USES ATP

Question 18

primary cilia

Answer 18

9+0 axonemal microtubule based internal structure
do NOT move, no motor proteins
mechano-receptors for fluid flow (liver)
SINGLE aka MONOCILIA
coordinated with cell cycle (must remake every division)

Question 19

nodal cilia

Answer 19

contain motor protein dynein
found in EMBRYO and important for development
Found around primitive node

Question 20

3 juntional complexes

Answer 20

occluding= tight
anchoring= adherens and desmosome
communicating= gap

Question 21

tight juntion/ occluding

Answer 21

most APICAL

a junctional COMPLEX made of occludin and claudins to form a SEAL

Question 22

occludin and claudins and JAM

Answer 22

found in tight junction/occluding in order to form seal

Question 23

desmosome/adherens

Answer 23

desmosome=intermediate filament, aderen=actin
anchoring junction
provide force RESISTANCE
transmembrane proteins: 1) desmogleins (Dsg) and 2) desmocollins (Dsc)

Question 24

gap juntion

Answer 24

transmembrane channels made of connexins to allow passage of stuff between cells

Question 25

connexins

Answer 25

transmembrane component of gap junctions that allow channels to be made

Question 26

List layers of epidermis

Answer 26

1) stratum basale- actively dividing with KERATINOCYTES 2) spinosum- desmosomes, thick 3) granulosum- prominent granule staining 4) lucidum 5) corneum- dead

Question 27

keratinocytes

Answer 27

cells giving rise to the epidermis

Question 28

stratum granulosum is full of?

Answer 28

keratohyalin granules containing cysteine rich and histidine rich proteins, precurse filaggrin

Question 29

Stratum corneum is full of

Answer 29

filaggrin that cross link keratin filaments in terminally dead cells to act as water barrier

Question 30

What layer of the epidermis is limited to thick skin?

Answer 30

stratum lucidum

Question 31

4 major epidermal cell types?

Answer 31

keratinocytes melanocytes= pigment (5%) langerhans cells= antigen presenting (2-5%) merkel's cells= sensory mechanoreceptors (6-10%)

Question 32

two layers of dermis

Answer 32

1) papillary- close to epidermis, type 1&3 collagen, contain blood vessels that feed stratum basale 2) reticular- deep and thick, irrigular collagen 1

Question 33

encapsulated nerve ending? (3 corpuscles)

Answer 33

``` pacinian= detect pressure and vibration meissener's= detect light touch ruffini's= detect skin stretch and torque ```

Question 34

free nerve endings penetrate?

Answer 34

the granular layer

Question 35

hair follicle

Answer 35

originates in hypodermis | responsible for making hair

Question 36

hair matrix cells differentiate to give rise to?

Answer 36

epidermal stem cells, melanocytes and keratin producing cells of hair

Question 37

hair completely made up of?

Answer 37

hard keratin | full of layers like skin

Question 38

eccrine sweat glands

Answer 38

INDEPENDENT of hair

Question 39

apocrine sweat glands

Answer 39

ASSOCIATED with hair follicle large luminal space SINGLE cell type= simple secretory epithelium

Question 40

secretory segment of glands is where?

Answer 40

buried deep in the dermis or upper part of hypodermis

Question 41

3 eccrine sweat gland cell types?

Answer 41

1) clear= secretory (stain intensely with PAS), numerous mitochondira and sER 2) dark= lots of rER and large Golgi 3) myoepithelial= can contract, responsible for expression of sweat, LIMITED to basale aspect

Question 42

Stratum spinosum is full of?

Answer 42

desmosomes

Question 43

myoepithelial cells

Answer 43

one type of Eccrine sweat gland cell LIMITED to basale aspect can contract, responsible for expression of sweat

Question 44

What two apical domain structures are mechanoreceptors?

Answer 44

Stereocilia- sensory info, found in ear | Cilia: primary cilia- nonmotile, sense fluid movement

Question 45

basal keratinocytes are attached to the basale lamina and dermis through?

Answer 45

hemidesmosomes (anchor intermediate filaments) and focal adhesions (anchor actin)

Question 46

does the epidermis have blood vessels?

Answer 46

no. Must cut dermis to 'bleed"

Question 47

cadherin and catenins

Answer 47

Cadherin (OUTSIDE of cell) is transmembrane protein in adheren junctions that connects to Calcium outside of the cell. Catenins link the cadherin to the actin cytoskeleton INSIDE the cell