Oral Biology Test Ii

Front 1

It is the most highly mineralized tissue in the body, consisting of more than 96% inorganic material in the form of apatite crystals and traces of organic material.

Back 1

Enamel

Front 2

Surface is not smooth, but has lateral stripes,called ____.

More numerous at what region?

Absent where?

Back 2

Perikymata
-Cervical (most numerous)

-Incisally//Gingivally (absent)

Front 3

What is the clinical correlation between perikymata and caries

Back 3

Teeth of many individuals are pitted. The perikymata and the pits provide attachment sites for bacteria (Clinically)

Front 4

Enamel covering can be described as ___ and ___.

Back 4

Thin and Hard

Front 5

Enamel is essentially completely ______.Very hard, resists ______.Very brittle, easy to ______.Susceptible to acid dissolution.

Back 5

Inorganic= Composition;
Attrition= Hardness;
Fracture= Brittle

Front 6

Scanning electron microscope shows that enamel is composed of long rounded structures called ______, or _____. Known as the building block of enamel

Back 6

Enamel Rods/Enamel Prisms

Front 7

Enamel rods originate at the _____ and extend to the tooth surface. No rods terminate or originate away from the _____.

Back 7

DEJ; DEJ

Front 8

Rod and interrod enamel is made up of crystallites._____and _____ minerals occurring variously as hexagonal crystals as the chief constituent of phosphate rock and of bones and teeth.
There is ___ difference in the orientation of the rod and interred crystallites.

Back 8

Carbonated Hydroxyapeptite; Calcium Phosphate Minerals; 45 degree

Front 9

Rod and interred enamel are separated by a space called the ____. This is an important diffusion pathway from the tooth surface to deeper enamel.

Back 9

Rod Sheath

NOTE:Prism sheath is not a structure,..it is a space and diffusion pathway

Front 10

What is made 1st Interrod enamel or enamel rods

Back 10

Inter- rod enamel

Front 11

Crystallites + Rod Sheath account for ___ percent of enamel volume

Back 11

10%

Front 12

Enamel crystals are ____ shape in cross section

Back 12

Hexagonal

Front 13

How long is an enamel crystal

Back 13

Not yet determined

Front 14

The stripped pattern on the inner 2/3 of enamel. Stripes are called _____.

Back 14

Hunter Schreger Bands

Front 15

T or F:HSB don’t really exsists, it’s the name given as a result of sectioning

Back 15

True

Front 16

An enamel rod that starts somewhere on the DEJ will go towards the surface, then twist parallel to the surface, then towards the surface again, several times to end up laterally and occlusally from its point of origin. Therefore there is thicker enamel occlusally, The purpose of the tortuous path of enamel rods is to

Back 16

Dissipate the tremendous forces of mastication thus reducing the incidence of enamel fractures.

Front 17

Forces are distrupted _____ and _____.

Back 17

Cervically and Laterally

Front 18

there is a Line of Retzius for every _____thus a 1:1

Back 18

Perikymata

Front 19

Lines of Retzius extending from the enamel surface to deeper enamel. The lines of Retzius are an important _____ for substances from the surface to subsurface enamel

Back 19

Diffusion Pathway (for lactic acid into enamel)
-Facilitate in enamel destruction
-Cervical region of tooth susceptible to bacterial attack

Front 20

Surface etch of teeth results three patterns: Name them?

Back 20

1)The rod is etched leaving sheaths.
2)Sheath areas etched deeper than rods.
3)Rods and sheaths etched at the same rate.

Front 21

Etching is due to these 3 things:

Back 21

Etching due to:
1) Crystal Orientation
2) Protein Protection
3) Reprecipitation

Front 22

_____are fan-like protein deposits found in the enamel at the DEJ. Origin, composition, and function are not known

Back 22

Tufts

Front 23

_____ are cracks in enamel and/or dentin that occur during tooth formation.
-filled w/ residual matrix material

Back 23

Lamellae

Front 24

____are extensions of odontoblast processes that extend into the enamel near the DEJ

HINT: Dentin Structure

Back 24

Spindles

Front 25

DENTIN is very different from enamel in several respects: Name 3 ways it is different.

Back 25

More organic (matrix is type I collagen)
More water
Viable tissue with cells

Front 26

Enamel is more than ___% inorganic

Dentin, bone and cementum are ___% inorganic.

Soft tissue is mostly water and organic material.

Back 26

Enamel 90%- Inorganic

Dentin, Bone, Cementum- 65%inorganic// 35% Organic

Front 27

_____ are long-term incremental growth lines. Perhaps comparable to the ______of enamel.

Back 27

Lines of Owen; Lines of Retzius

Front 28

______are daily incremental growth lines in dentin.

Back 28

Lines of Von Ebner

Front 29

Acid etching dentin removes the mineral and reveals the ____matrix.

Back 29

Collagen

Front 30

Humans have ____ (there are many other kinds of dentin).

The dentin near the DEJ is _____.

The remainder of the dentin is ______.

Back 30

Orthodentin= Humans;

Mantle dentin= dentin near DEJ;

Circumpulpal Dentin=remainder dentin

Front 31

With age the dentinal tubules _____ as new dentin is deposited. The dentin at the periphery of tubules is ____ dentin.

Back 31

Constrict; Peritubular

Front 32

T or F:Peritubular dentin has different characteristics from intertubular dentin

EX:Calcium staining showing high mineral content of ____ dentin

Back 32

True; Peritubular Dentin= high mineral content

Front 33

After a tooth comes into occlusion, dentin continues to be deposited, but at a slower rate. Dentin formed after occlusion is called ____ Dentin

Back 33

Secondary Dentin

Front 34

Trauma results in localized formation of additional dentin within the pulp. This is ______. Some texts also refer to this as physiologic dentin or reparative dentin.

Back 34

Tertiary Dentin

Front 35

T or F:The tubules of tertiary dentin may or may not line up with the dentinal tubules of circumpulpal dentin.

Back 35

True

Front 36

Where is peritubular dentin located? Is it calcified?

Back 36

Walls of tubules; highly calcified

Front 37

Where is intertubular dentin located? Is it calcified?

Back 37

In between tubules; highly calcified

Front 38

Mantle dentin is the ___ layer of dentin and is the ___ to form

Back 38

Outermost; first layer to form

Front 39

Circumpulpal dentin is located where?

Back 39

Around the pulp,...formed after mantle dentin

Front 40

Which is more mineralized: Primary or Secondary Dentin

Back 40

Primary- develops at a faster rate

Front 41

Secondary Dentin
_____= rounded islands of mineralization either free in soft tissue or attached to the dentin.

Back 41

Denticles

Front 42

T or F: Dentinal tubules close with age

Back 42

True

Front 43

T or F:Mineralized tubules result in sclerotic dentin. Translucent.

Back 43

True

Front 44

Cementum is either cellular or acellular.
Acellular Cementum (primary)
_____= unmineralized layer
_____ layers formed. At least one layer over root, more in ____third. Formed ____ than cellular cementum. Has No cells. Width of layer never or always changes; Acellular cementum is the area for ____.

Back 44

Cementoid; 1st layer formed; cevical; formed slower than cellular cementum; Width NEVER changes; attachment

Front 45

Cellular cementum (secondary)
_____in lacunae with canaliculi. Formed after acellular. Many layers in ____third. More layers with time. Not in ____or ____. Very similar to____.

Back 45

Cementocytes; Apical 1/3;Not in the Incisors or Canines; Bone

Front 46

Intrinsic: fibers from ____
Extrinsic: fibers from ____

Back 46

Cementoblast= Intrinsic;
Fibroblast of PDL= Extrinsic

Front 47

Tooth formation starts at about the ____week of development

Back 47

5th

Front 48

Tooth development begins @ the ___ week of development?

Back 48

5th

Front 49

Neural Crest Derived Mesenchyme is induced by epithelium to produce ____

Back 49

Condensed Mesenchym

Front 50

Condensed Mesenchyme will differentiate in to what two structures

Back 50

Dental Sac and Dental Papilla

Front 51

Dental Papilla will become ____(dentin) and ____.

Back 51

Odontoblast and Pulpal Fibroblast

Front 52

Dental Sac will become the ____, _____ (cementum) and ___.

Back 52

PDL, Cementoblast and alveolar bone

Front 53

Name the 4 stages of tooth development

Back 53

Dental Lamina, Bud, Cap, Bell

Front 54

Incisor develop in the late ___ stage

Back 54

Bell

Front 55

Molars develop in the early ___ stage

Back 55

Cap

Front 56

Morphogenic Determinant is in the ____

Back 56

Mesenchyme

Front 57

Mesenchymal cells send processes that contact and become anchored to the ____.


Anchoring fibers are type ___ collagen

Back 57

Basement Membrane; Type VII

Front 58

Structure of the basement membrane, mostly type ____collagen.
Some of the large molecules that interact to form the basement membrane.
Fibronectin hyaluronan
Collagen IV
decorin
Laminin perlecan
Tenascin aggrecan

Back 58

Type IV- BM

Front 59

Cells attach to the extracellular matrix via ____, transmembrane molecules. On the cytosol side, integrins are connected to the _____.

Back 59

Integrins; Cytoskeleton

Front 60

Composite of how molecules of cells may attach to, and interact with the molecules of the extracellulare matrix.
The cytoskeleton is attached to the integrin via ________, ______, and ______

Back 60

Paxillin, Talin, Vinculin

Front 61

Paxillin stains:

Vinculin// Talin stains:

Back 61

Ameloblast and Odontoblast

ONLY Ameloblast, not odontoblast

Front 62

Define Condenstion:

Back 62

Site where large numbers of mesenchymal cells become attached to the basement membrane within short distance (short time?).

Front 63

Mesechymal cells quickly differentiate into odontoblast and secrete dentin matrix (type __collagen)

Back 63

I

Front 64

The first collagen secreted is mantle dentin, characterized by very large collagen fibers called _____.

Back 64

Von Korff's Fibers

Front 65

Mineralization of dentin first occurs within ____.

Back 65

Matrix Vesicles

Front 66

T or F: Mineralization of matrix vesicles spreads to surrounding collagen forming islands of mineralized tissue

Back 66

True

Front 67

Islands of mineralized dentin fuse to form the ___ dentin.
Note that no enamel has formed yet, but the ____ have elongated and the organelles for protein synthesis are in place.
There is some evidence that some enamel matrix proteins have been secreted into the dentin at this stage

Back 67

Mantle; Pre-Ameloblast

Front 68

Enamel matrix is deposited when

Back 68

ameloblasts contact mineralized dentin

Front 69

_____ and _____of mantle dentin forming the DEJ

Back 69

Enamel Matrix and Von Korff's Fibers

Front 70

Name the stages of Amelogenesis

Back 70

Amelogenesis
Presecretory stage
Secretory Stage
Transition
Maturation Stage
Reduced Stage

Front 71

Stopped @ Slide 127,...Start of Mechanisms of Bone Formation and Mineralization

Back 71

Stopped @ slide 127,..Start of Mechanisms of Bone formation and Mineralization

Front 72

Name 2 ways bones form

Back 72

Endochondrial Ossification (requies cartilage precursor) and Mesenchymal Ossification

Front 73

In endochondrial ossification the cartilage matrix (type ___ collagen) must be removed and replaced by bone matrix (type ___ collagen)

Back 73

Collagen Matrix (Type II)

Bone Matrix (Type I)

Front 74

Name the different pathways a mesenchymal cell can differentiate into upon environment, growth factors, or hormonal stimulus.

Back 74

Fibrogenic (low cell density)
Myogenic
Chondrogenic (high cell density// low O2 tension)
Osteogenic (high O2 tension)

Front 75

Osteoblast synthesize

Back 75

Type I collagen
Alkaline Phosphatase
Osteocalcin
Collagenase
Prostaglandins

Front 76

Resorptive Cells that contain acid phosphatase,collagenase, cathespins, and plasminogen activator

Back 76

Osteoclast

Front 77

These cells cover the surface of bone,..function is unknown

Back 77

Bone Lining Cells

Front 78

Name te two stages of mineralization?

Back 78

1-Nucleation by a pure solution/ foreign material;
2-Crystal Growth

Front 79

Name the 3 ways that mineralization may occur

Back 79

Increasing Ca or Phosphate concentrations next to unmineralized area

Removal of inhibitors of mineralization (PPi, Mg, Ca binding proteins, Proteoglycans)

Synthesis of molecules that will promote mineralization (collagen, phosphoproteins, gamma carboxyglutamate, phospholipds)

Front 80

Osteocalcin=

low or high mw

binds loosely or tightly to Ca++

contains ____that is post-transitionally modified,..vitamin K dependent

only in bone or other places in the body

measures ____ activity

Back 80

low MW

Binds tightly to Ca++

Contains GLA- Gamma CarboxyGlutaminic Acid

Restricted to BONE

Measures Osteoblastic Activity

Front 81

Phospholipids=

Histologically stain in the _____in endochondrial bone formation, @ predentin-dentin interface. Also at sites of _____ formation

Can serve as nucleation factors in _____deposition

Back 81

Hypertrophic Zone; Enamel formation

Hydroxyapeptite deposition

Front 82

High Serine Phosphoproteins=

found in low or high concentrations in bone/dentin

Serine residues bind to ____.

Back 82

High

Bind to Phosphate

Front 83

Collagen (in bone)=

Post-trascriptional modification differ due to a greater extent of ____ and ____.

Crosslinks are the same or different

Vitamin D def, can alter what

___ and ___ inhibit mineralization

Back 83

Lysine Hydroxylation and Glycolysation

Cross-links are different

Crosslinking of Collagen Fibers

Mg and PPi= inhibit mineralization

Front 84

PPi is made via the hydrolysis of ____.

What E catabolize PPi afterwards to make sure it doesnt interfere w/ bone mineralization

Analogs of PPi are ____ and also inhibit mineralization

Back 84

ATP

Alkaline Phosphotase//Pyrophosphatase

Phosphonates

Front 85

Mg inhbits mineralization,..what happens if there is a def of Mg.

Back 85

Hypermineralization
-inspite of low ca in blood serum (to signal mineralization)

Front 86

GAG's bind to Ca- this decreases or increase as mineralization proceeds

What is the GAG that predominates in bone mineralization.

Back 86

decreases

Chondrotin Sulfate

Front 87

Cellular control of bone mineralization is dependent on the presence of a ____.

Back 87

Bone Membrane

Front 88

Mitochondria accumulate ___ and ____.

Ca gradient in mitochondria increases in cartilage to what level

Back 88

Ca and Phosphate

Level of Calcification and then disappears

Front 89

Matrix vesicles=

Have a _____ in interior.

Arise from ____ by budding

High ____ and _____ enzymatic activity

Secreted in areas of ____

Back 89

Amorphous Ca Phosphate in interior

Plasma Membrane

Alkaline Phosphatase and ATPase Enzymatic Activity


Calcification

Front 90

What is sooooooo important about Bone Morphogenic Matrix

How many exisists

Back 90

Well, it is decalcified, cell free bone powder that initiates cellular differentiation in cartilage and bone lines of embryonic tissue,...could be used as an IMPLANT MATERIAl

9

Front 91

Bone composition=

% Inorganic, Organic, Water

Back 91

60% inorganic

25% organic- collagen accounts for 90% of this

15% water

Front 92

Ca circulates in plasma in one of three ways,...name them?

What is the most common way Ca is carried?

What is the protein that Ca is bound to in the plasma

Back 92

Ionized, Protein Bound, and complexed

Ionized; (50%) Albumin:

Front 93

What does complexed Ca mean?

Back 93

Ca is carried by other molecules such as phosphate or citrate

Front 94

What is the major affect of hypocalcemia/hypercalcemia?

Back 94

Hypo-Muscular Tetany

Hyper-Lethargy,GI probs, cardiac arrthmyias, calcification of soft tissues

Front 95

Approx. ___of Skeletal Ca is exchangable w/ ECF

Back 95

1%

Front 96

The majority of Ca, P, and Mg is where in the body?

Back 96

Skeleton

Front 97

Mg and Ca are mainly in the ___ forms in the plasma and P is mainly in the ___ form.

Back 97

Ionized; Complex

Front 98

Serum Ca levels are mainly controlled by what three factors

Back 98

PTH, Calcitonin, Vitamin D

Front 99

PTH increases/decreases PLASMA Ca

Back 99

Increase

Front 100

PTH is a ___ chain PP made of ___ aa lacking ___.

Back 100

Single;84aa;cysteine

Front 101

1-34 aa amino terminal sequence in PTH has what importance

Back 101

Mobilization of Ca activity

Front 102

PTH is synthesized as a ____ hormone w/ 37 aa added to the amino terminal end

Two cleavages occur,..name where?

Back 102

Preprohormone; cleaved @ 31//6 aa

Front 103

What stimulates PTH secretion primarily and secondarily

Back 103

1- low Ca levels
2- low mg levels

Front 104

Where is PTH degrades

Back 104

LIVER and Kidney

Front 105

What does PTH do when it is active?

Back 105

Mobilize bone Ca and activates activity of Vitamin D metabolism in Kidney

Front 106

Calcitonin (CT) decreases/increases plasma Cs

Back 106

Decreases

Front 107

CT has ____ aa in a single PP chain

Back 107

32 AA

ALL are needed for function

Front 108

CT is secreted from where

Back 108

Parafollicular cells in Thyroid

Front 109

What triggers CT secretion
(2 things)

Back 109

High Ca (ionized) levels and Gastrin

Front 110

1/2 life of CT is ___

Back 110

4-5 min

Front 111

What is CT function?

Back 111

Block PTH activity on bone

Front 112

Vitamin D increases/decreases plasma Ca?

Back 112

increases

Front 113

7-dehydrocholesterol is converted into cholecalciferol (vit D3) by ____ in skin

Back 113

UV irradiation in skin

Front 114

Vit D3 is converted hydroxylated @ the 25th position in the ____ yielding _____.

Back 114

Liver- 25 OH

-Loosely controlled

Front 115

25-OH is hydroxylated at the 1 postion in the ____ to yield____. THe E for this rxn is ____.

Back 115

Kidney; 1,25 (OH)2 Vit D3
Renal 1 alpha Hydroxylase

Tightly controlled

Front 116

What does vit d3 do when active?

Back 116

Increase Ca absorption in GUT// acts secondarily w/ PTH on Ca in bone

Front 117

Def of Vit D3 in children is called ___ and in adults is called ____.

Back 117

Rickets// Osteomalacia

Front 118

Bone resorption can be defined as removal of both _____ and ____ that is mediated by ____.

Back 118

Mineral Phase + Matrix

Mediated by Osteoclast

Front 119

Osteoclast are SMALL multinucleated,cells w/ normal looking nuclei,...T or F

Back 119

F:Large cells, Multi-nucleated w/ Irregular Shaped Nuclei

Front 120

Osteoclast actively resorbing bone show this structure

Back 120

A ruffled border

Front 121

Osteoclast stain for ____, and contain ____ receptors.

Back 121

Tartate Resistant Acid Phosphotase, Calcitionin

Front 122

Osteoclast dont respond to PTH directly,...instead they respond to what?

Back 122

Secretory products of PTH stimulated by osteoblasts

Front 123

____ are known to aid in the bone resorption process by degrading collagen @ acidic pHs

Back 123

Cathepsins

Front 124

Name 3 situations in which bone resorption exceeds bone formation?

Back 124

1)Hyperparathyroidism (imbalance in Ca homeostatic metabolism)

2) Infection//Inflammation activates bone cells by cytokines and other inflammatory mediators produced by immune/inflammatoru cells

Lack of mechanical stress on bone (basically you dont use,..you lose)

Front 125

Name the age:

Excessive resorption is coupled w/ decreased bone formation

Back 125

Post-Menopausal Women

Front 126

Decreased rates of bone formation and decreased rates of bone formation

Back 126

Elderly

Front 127

Resorption increase w/ normal rates of bone formation

Back 127

Pre-Menopausal Women

Front 128

T or F,...PTH when given at pulsated doses can stimulate bone formation

Back 128

TRUE!

Front 129

In vivo,..PTH is associated w/

Back 129

Increased Osteoclasts

PTH also stimulates bone resorption on organ culture

Front 130

Necessary permissive cofactor for PTH but does not stimulate bone resportion in vivo

When does it stimulate bone resorption

Back 130

Vit D3

Organ Culture

Front 131

Calcitonin is most affected by what

Back 131

Its antagonist- PTH

Front 132

This molecule is known to stimulate Osteoclast activity,..in fact it is called an osteoclast activating factor

Back 132

IL-1

Front 133

This molecule,..like IL-1 stimulates osteoclast activity: it is the primary mediator of immune and inflammatory processes,...stimulates bone resorption in vivo// in vitro

Back 133

TNF

Front 134

This molecules is produced by osteoblast to aid in bone resorption w/ osteoclast.

Name the molecule that works w/ this molecule in sitmulating stem cell populations leading to osteo clast

This molecule works w/ ____ in organ culture in bone resorption

Back 134

IL-6

IL-3

IL-1

Front 135

When macrophages are exposed to stimuli these molecules are potent stimulators of bone resorption in Organ culture

Back 135

Prostaglandins
Esp- PGE2

Front 136

Excessive glucocorticoids is associated w/ what

Back 136

Increased bone LOSS

Front 137

Def Androgens and Estrogens are associated w/ what

Back 137

Increased bone MASS

Front 138

___ loss is associated w/ osteoporosis in post-menopausal women

HOW?

Back 138

Estrogen; Estrogen sensitizes bone cells to the effects of circulating PTH (makes them more responsive)

Front 139

____ has been shown to slow osteoclast activity w/ no affect on bone formation

Back 139

Estrogen Therapy

Front 140

Estrogen inhbits this molecule

Back 140

IL-6 being released from osteblast

Front 141

Resorptive affects of ___ and ___ are dose dependent and can stimulate bone formation

Back 141

PTH and Prostaglandins

Front 142

___ and ___ lead to increase bone fragility

Back 142

Cadmium and Lead
-Inhibits syntheis of Vit D3

Front 143

___ is a necesary factor for normal bone growth and maturation

Back 143

Zn

Front 144

What occurs during cellular differentiation

Back 144

Cells are responding to changes in there external enviornment...so they are altering there genome activity by changing there genetic expression which is most of the time irreversible

Front 145

How does the cell know that there is a change in the external enviorment

Back 145

It recieves a signal,...this signal affects transcription

Front 146

Name some of the most common primary signals that a cell recieves that affect transcription

Back 146

Growth Factors
Hormones
Retinoic Acid// Derivatives

Can come into the cell or act on the surface of the cell

Front 147

Signals acts in two ways to affect transcription,...name them?

Back 147

Directly- act as a transcription factor

In directly- affect the activity of a transcription factor

Front 148

How does a steroid hormone work?

Back 148

Crosses cell membrane, binds to an intracellular receptor,.. attaches to HORMONE RESPONSE ELEMENT in genome and activates 50-100 genes

Front 149

____ modulate intracellular events via G. Proteins, Tyrosine Kinases (DIRECTLY), Tyrosine Kinase associated mechanisms , Serine-Threonine Kinases or alteration in ion channels

Back 149

Cell Surface receptors

Front 150

Cytokines may direclty activate ____ by phosphorylation of a TYROSINE residue or indirectly activate through a ___

Back 150

STAT (Signal Transducer and Activator of Transcription; JAS (Janus Kinase

Front 151

Different second messengers,..like cAMP activate these 2 pathways

Back 151

MAP (mitogen activated protein) kinase pathway

RAS

Front 152

Give and example of physical re-arrangement of the genome

Back 152

Linking of the V, D, and J segments to a C gene segment in B- Lymphocytes

Front 153

What is a feed-back loop

Give and example

Back 153

When a regulatory protein activates its own transcription factor to ensure the gene is ALWAYS expressed

Myo-D transcription factor in muscle

Front 154

_____ is the reason for the differences in tissue type

Back 154

Pattern Formation

In some tissues,..position is important (ie teeth)

Front 155

How does limb formation begin

Back 155

By Bilateral outgrowths lateral plate mesoderm surrounded by epithelium

Front 156

How does a limb bud know where to grow

Back 156

by Fibroblast growth factor 8 (FGF-8)
- in fact implantation of FGF8 will stimulate limb bud formation

Front 157

2nd- The Bilateral outpockets in mesoderm (surrounded by ectoderm gets ____ along the apex and into the ____.

As this is occuring the posterior ____ forms the zone of ______.

Back 157

Thicker; Apical Ectodermal Ridge (AER)

Mesenchyme; Zone of Polarizing Activity (ZPA)

Front 158

What is the Zone of Polarizing Activity resposible for?

Back 158

Anterior-Posterior Patterning of the digits (pinky to thumb)

Front 159

ZPA is mediated through what protein

Back 159

SHH (Sonic Hedge-Hog) Protein??

Front 160

Grafting of cells from a ZPA to the anterior portion of the limb bud resulted in what?

What does this mean?

Back 160

Resulted in Mirror Image formation of digits

ZPA is involved in Pattern formation

Application of SHH does the same thing,..so they work together

Front 161

The Apex Ectodermal Ridge (AER) regulates what?

Back 161

Proximal-Distal (shoulder-digits)

Front 162

Removal of AER results in what

Removal of AER @ successive later stages @ later stages results in what

Back 162

Trucation of the Limb

Progressive loss of more and more distal elements

Front 163

AER functions through the release of ___ by it maintaining the cells beneath (progress zone) the apical ectodrmal ridge

Back 163

FGF's

Front 164

W/ the loss of this receptor an embryo will be limbless

Back 164

FGFR2 receptor

-Uncouples FGF8-FGF-10

Front 165

Dorsal-Ventral (back of hand) to palm is specified by what three factors

Back 165

En-1, Wnt7a and Lmx-1

interactions btw the three fine tune positional information

Front 166

___ induces ectopic bone and cartilage formation

Back 166

SHH

Front 167

____, ____,and ____, work together to stimulate mesenchymal cell progression into chondrocyte linage

Back 167

SHH, BMP2, Ihh (indian hedge-hoge)

-also regulate Pre-osteoblast differentiating into osteoblast

-Parathyroid hormone related peptide also aids in this process

Front 168

BMP belongs to the ____ superfamily of growth and differentiation factors

Back 168

TGF-B Superfamily

Front 169

____ and ___ are expressed in perichondrium of developing limbs but ____ is absent in joints

Back 169

BMP2 and 7; 7

Front 170

Retinol A is metabolized into ____ and _____

Back 170

Retinal and Reinoic Acid

Front 171

____ (AKA:____) during pregnacy will result in defects of the ear, mandible, secondary palate, thymus, and heart

Back 171

Accutane (13-cis reinoic acid)

Front 172

In limb formation ___ incuces production of polarizing signals

Back 172

Retinoic Acid

Front 173

These genes are required for the proliferation of skeletal progenitor cells

Back 173

Hox genes
-4 hox gene clusters= code for 39 genes= encode homeodomain Transcription factors

Front 174

Hox gene combo determine length of upper arm (__ and __) lower arm (___, ___, ___) and digits ( ___, ___, ___)

Back 174

Upper arm= 9, 10

Lower arm= 10, 11, 12

Reduction in gene dose will result in trucation of the corresponding anatomical regions

Digits= 11, 12, 13

Front 175

Responses to the ECM are most likely mediated through the ___

Back 175

Integrin (link ECM w/ cell membrane and interal structures)

Front 176

Can a differentiated cell change

Back 176

Yes if put under the appropriate conditions

Front 177

Do osteoclast have receptors for PTH

Back 177

NO

Front 178

Name three factors that are important in the control mechanisms in regulating osteoclast differentiation

Back 178

RANK

RANKL

Osteoprotegerin