Collagen Structure and Function (1 + 2) Flashcards
1
Q
What proteins does the stromal matrix of connective tissue contain?
A
hyaluronan
proteoglycans
glycosaminoglycans
2
Q
What inherited disease is due to mutations in the COL7A1 gene, resulting in fragile skin that blisters easily and can be sloughed off?
A
dystrophic epidermis bullosa
3
Q
Collagen arranged in parallel bundles would be found in what tissue?
A
tendons and ligaments
4
Q
What are the functions of extracellular matrix in cartilage?
A
- support and locomotion
- resilient shock absorber
5
Q
Which protein cleaves the C-terminal peptide off of the procollagen molecule?
A
BMP1
6
Q
The ____ refers to the basal lamina combined with the layer of tethering collagen fibrils.
A
basement membrane
7
Q
What collagens make up the non-fibrillar collagens (major and minor)?
A
IV, VI, VII, VIII, IV, X, XII, XII-XXIII, XXV, XXVI, XXVIII
8
Q
Which protease is responsible for cleaving off the N-propeptide?
A
ADAMTS2, 3, 14
9
Q
What are the main steps of collagen biosynthesis or assembly?
A
- synthesis of a pro-a chain
- formation of a procollagen triple helix
- formation of procollagen trimer
- formation of tropocollagen
- aggregations of collagen fibrils form collagen fiber
10
Q
Type __ collagen is found only in the narrow zone at the DEJ; Type __ collagen is found in the enamel organic matrix adjacent to DEJ.
A
IV; VII
11
Q
___ accelerates protein folding during collagen biosynthesis.
A
FKBP10 (peptidyl prolyl cis-trans isomerase)
12
Q
What is the primary role of type VII (7) collagen in both the basal lamina AND at the DEJ?
A
anchoring
13
Q
Which proteins act in lysyl hydroxylation in collagen biosynthesis?
A
PLOD2
14
Q
What are the key components of the basal lamina?
A
- Glycoproteins (laminins, nidogen)
- Collagens (IV)
- Proteoglycans (perlecan)
15
Q
Collagens arranged in a swirling pattern around dentinal tubules are found where?
A
in teeth
16
Q
In most connective tissues, ____ secrete the extracellular matrix.
A
fibroblasts
17
Q
____ syndrome leads to issues with kidney filtration, blood in urine, burning sensation while urinating, and nephritis, eventually leading to acute renal failure.
A
Goodpasture
18
Q
Which fibers of the periodontal ligament are obliquely-positioned and located in the middle of the root?
A
oblique fibers
19
Q
In those forms of OI where the Type I collagen genes themselves were not mutated, what could you suspect to be the cause of these types of OI?
A
potentially issues or mutations in the post-translational modifications of pro-collagen processing
20
Q
In what syndrome are there autoantibodies produced against the Type IV collagen alpha-3-chain?
A
Goodpasture
21
Q
What is the other form of OI that actually express no mutations in collagen genes?
A
Type V OI
22
Q
Which type of collagen regulates the spacing of Type II collagen fibrils?
A
Type XI
23
Q
The ___ separates epithelium from the underlying connective tissue stroma and is primarily made up of Type IV collagen.
A
basal lamina
24
Q
The ___ is composed of many proteins with various properties assembled into an organized network/meshwork, often associated with producer cells.
A
extracellular matrix
25
What type of collagen found in teeth is the major ECM component of dentin, cementum, the the periodontal ligament (PDL)?
Type I collagen
26
What component of ECM accounts for tensile strength?
collagen (fibrillar component)
27
What enzyme in collagen biosynthesis catalyzes the formation of interchain disulfide bonds between cysteines during the nucleation of the polypeptide chains?
PDI (protein disulfide isomerase)
28
Type __ collagen is important in dermal reticular fibers, along with small amounts in dentin.
III (with V)
29
What type of experiment would you conduct if you found two diseases to have a very similar phenotype but associate with completely different genes?
conduct an experiment to determine if these totally different genes interact with a common pathway at some point
30
When can fibril formation occur in collagen biosynthesis?
after the C and N propeptides have been removed from procollagen to form tropocollagen
31
What specialized matrix separates connective tissue stroma and epithelium?
basal lamina
32
What is the secondary structure collagen helix stabilized by?
static repulsion of pyrrolidone rings of proline and hydroxyproline residues
33
Which types of OI have no mutations in Type I collagen genes?
V and VI-XVI
34
What layer of connective tissue is important in cell polarity?
basal lamina
35
Which type of EDS is unique in that its mutations are located in the N-terminal protease cleavage sites of collagen biosynthesis?
Arthrochalasia
36
Type __ collagen may regulate the assembly of type II collagen fibrils.
IX
37
Is the banding in fibrillar collagen lightly or darkly stained where there are no gaps in the collagen molecules?
light
38
Mutations in COL4A are associated with what disease?
Alport syndrome
39
What happens when CRTAP is mutated?
mutations in CRTAP cause defective prolyl-3-hydroxylation which delays collagen folding
40
Collagen, elastin, and fibrillin are ____ proteins.
structural
41
What are some characteristics of achondrogenesis type II?
- hypercellular epiphyseal cartilage
- poor or absent growth plate
- diminished ECM
- thick irregular collagen fibers
42
What material makes up the majority of dentin?
collagen (mostly Type I, with some III and V)
43
What type of fibrous proteins help cells attach to ECM?
adhesive (fibronectin, vitronectin, laminin)
44
In polypeptide nomenclature, where is the collagen type noted?
a1(II)
at the (II)
45
What enzyme glycosylates selected hydroxylysines in the synthesis of collagen?
collagen glycosyltransferases
46
What is the major structural component of ECM?
collagen (25% total protein mass in mammals, 90% of material in bone/dentin)
47
Why is hydrogen bonding so important in collagen?
the bonds stabilize the triple helix
48
What are the 5 classified groups of collagen in the gingiva?
- dentinogingival
- alveogingival
- circumferential
- periosteal
- transseptal
49
Type II OI can occur as an autosomal dominant mutation, but occurs mainly as ___.
a spontaneous mutation due to perinatal lethality or parent mosaicism
50
What are the driving forces of the tissue and ECM?
the functional requirements of it, such as available matrix components and metabolic costs
51
Which residue is especially affected in Type II OI?
glycine
52
____ encode for vast ECM components and can be used to assemble ideal ECM for a given tissue.
Genes
53
Bone and teeth have ____ ECM.
hard, calcified
54
What are the roles of extracellular matrix in embryonic development?
cell adhesion
cell migration
tissue morphogenesis
55
Glycine has the ___ side chain of the gly-X-Y complex of collagen.
LEAST bulky
56
Mutations of what two Type I collagen genes are associated with osteogenesis imperfecta?
COL1A1 and COL1A2
57
What are the functions of the collagen fibers in the gingiva?
- anchoring gingival tissue to tooth/alveolar bone
| - resisting masticatory forces
58
Where does nucleation of the procollagen triple helix occur?
at the C-propeptide
59
Which type(s) of dentinogenesis imperfecta is due to mutations in DSPP?
Shields Type II and Shields Type II
60
Mutations in Type II collagen can cause ____.
chondrodysplasias
61
What cells and structures are found in the stroma?
```
fibroblasts
collagen fibers
elastic fibers
capillaries
macrophages
```
62
Classical osteogenesis imperfecta is due to ___ or ___ abnormalities of Type I collagen. What does this mean?
quantitative; qualitative; the amount or the quality of type I collagen
63
___ can be caused by mutations in the Type I collagen genes OR in genes encoding proteins involved in post-transcriptional modifications or regulation of collagen biosynthesis.
Osteogenesis imperfecta
64
What is a D-period?
pair of a lightly-stained and a darkly-stained region of fibrillar collagen
65
What accounts for the less-rigid structure and greater flexibility of non-fibrillar collagens?
the shorter triple-helical domains interrupted by non-collagenous sequences
66
Chondrodysplasias are linked to mutations in what type of collagen?
Type II (cartilage)
67
What are the major collagens in the non-fibrillar collagens?
Type IV, VI, VII
68
Which type of EDS is characterized by joint hypermobility?
hypermobility EDS
69
Which types of collagen are found in the enamel organic matrix region at the DEJ?
Type IV and Type VII
70
Mutations in any of what complex can lead to many different types of autosomal recessive OI's independent of mutated Type I collagen?
the prolyl hydroxylation complex
71
What underlies all epithelial cell layers?
basal lamina
72
Which type of OI has a severity level between Types I and III?
Type IV
73
What accounts for the characteristic banding of fibrillar collagens?
quarter-staggered array
74
Which types of EDS are caused by mutations in collagen genes?
classical
hypermobility
vascular
arthrochalasia
75
Which types of OI are actually considered to be autosomal recessive?
Types VI-XVI
76
What are some ways that collagen function can be mutated and disrupted?
- collagen genes themselves
- enzymes involved in post-translational modification
- developing an antibody against collagen
77
What is collagen's quaternary structure?
3 helical a-chains stabilized by hydrogen bonds between glycine and residue X
78
____ collagens are large collagenous domains of about 1000 amino acids.
Fibrillar
79
Type __ collagen is found in cartilage and in eyes. It helps to regulate spacing and diameter of Type II collagen fibrils.
XI
80
The ___ protein modifies collagen expression in moderate to progressively-deforming OI.
WNT1
81
Where does collagen biosynthesis occur?
in compartments of the ER and Golgi
82
Why is the basal lamina important?
its filtering (glomerulus) and anchoring/attachment capabilities + cell polarity, cell metabolism, cell survival and proliferation
83
Which protein is involved in the lysyl hydroxylation of collagen and leads to moderate to severe OI?
PLOD2
84
A collagen fibril's strength can be attributed to ____.
collagen cross-linking
85
What kind of material can ECM be viewed as? Why?
composite material; because many different components with different mechanical properties combine and organize to create a tissue with optimal properties
86
Hydroxylation, glycosylation, and intrachain disulfide bonding are all ____ modifications that occur in the beginning stages of collagen biosynthesis.
post-translational
87
What component of ECM accounts for the elasticity or resilience?
elastin (elastic fibers)
88
Which type of OI has mutations in COL1A1, but rarely in COL1A2?
Type IV
89
What is the principal type of collagen found in cartilage matrix?
Type II collagen
90
Collagen arranged in orthogonal lattices are found in ___.
the corneas
91
What are the resulting phenotypes in a mutation of any one of the different proteins associated with the same pathway?
the phenotypes for each would be very similar, even if the protein mutated was different
92
From what developmental lineage are stromal cells derived?
mesoderm
93
What types of collagen mutations are linked to Ehlers Danlos syndrome?
- mutations in fibrillar collagens Types III and V
| - mutations in enzymes involved in post-translational modifications of collagens
94
Type I collagen is a heterotrimer of __ a1(I) chains and __ a2(I) chains encoded by two separate genes.
2; 1
95
What types of collagen are heterotrimers?
Type I and Type VI
96
Which type of OI results from mutations in the COL1A1 and COL1A2 that produce abnormal pro-alpha collagen chains that become incorporated into collagen trimers and disrupt the triple helical structure?
Type II OI
97
Which type of OI is characterized by short statuure, spinal curvature, severe bone deformities, and blue sclera?
Type III OI
98
Which proteins facilitate prolyl hydroxylation in collagen biosynthesis?
CRTAP
LEPRE
PPIB
99
What type of deficiency results when normal trimers are formed, but only half of the normal collagen is produced?
quantitative deficiency; In Type I OI, since only one allele is active and producing, only half of the normal collagen is produced
100
Mutations in prolyl and lysyl hydroxylases, FKBP10, collagen glycosyltransferases, PDI, or Hsp47 could all potentially lead to what condition?
autosomal recessive OI, or Types V-XVI (types of OI with no mutations in the Type I collagen genes)
101
___ fibers hold the attached gingiva against the bone.
Periosteal
102
What component of ECM accounts for resilience or resistance to compression?
proteoglycans
103
Which two non-fibrillar collagens have an important role in the basement membrane?
Type IV and Type VI
104
What makes up the majority of bone, cartilage, and teeth (specialized connective tissues)?
extracellular matrix
105
What confers the twist in the collagen helices that prevents other secondary structures from forming?
proline
106
What protein is responsible for cleaving off the C-propeptides on procollagen?
BMP-1 or tolloid proteinases
107
What do all collagen molecules contain at least one of?
one triple-helical region called a collagenous domain
108
Fibronectin, vitronectin, and laminin are ____ proteins.
adhesive
109
Type I collagen fibrils, oxytalan fibers composed of fibrillin, and Sharpey's fibers are all components of the ____.
periodontal ligament (PDL)
110
Corneas have ___ ECM.
optically transparent
111
What makes up the complex that carries out collagen prolyl hydroxylation?
CRTAP
Cyclophilin B (PPIB)
Prolyl-3-hydroxylase 1 (LEPRE1)
112
____ is a type of EDS caused by a mutation in PLOD1.
Kyphoscoliosis
113
___ collagen is a homotrimer encoded by the COL2A1 gene.
Type II
114
What does a CRTAP null mutation result in?
lethal form of OI (Type II)
115
What types of collagen are homotrimers?
Type II
116
Patients with epidermolysis bullosa (EB) have mutations in what type of collagen?
7 (VII)
117
What are the amino acids found in collagen fibers?
glycine, proline, hydroxyproline, alanine, serine, lysine, hydroxylysine
118
What are some symptoms of scurvy?
```
lethargy
bleeding gums
bone pain
fragile vessels
loosening of teeth
```
119
What structures contain specialized mineralized connective tissues?
teeth and bone
120
A wickerwork pattern of collagen would be found in what tissue? Why?
skin; resists tensile stress in multiple directions
121
What are the collagen fibrils crosslinked by after their formation? Why is this important?
lysines of adjacent molecules; greatly increases tensile strength
122
Which type of EDS is characterized by skin hyper-extensibility?
classical EDS
123
At what stage does collagen crosslinking by lysyl oxidases occur?
after the formation of tropocollagen
124
____ are trimeric molecules consisting of 3 identical (homotrimeric) or non-identical (heterotrimeric) polypeptide chains (alpha-chains).
Collagens
125
What is the only calcified tissue that does not contain abundant collagen?
enamel
126
What dictates the composition of extracellular matrix in each tissue?
the biochemical and functional requirements of the tissue
127
What are the mechanical properties of a tissue?
amount and type of ECM macromolecules present and their organization
128
The ___ and ___ have a stromal matrix containing collagen.
gingiva; periodontium
129
____ OI is usually autosomal dominant, but can sometimes be autosomal recessive.
Type III
130
Is osteogenesis imperfecta primarily autosomal dominant or autosomal recessive?
autosomal dominant
131
Which type of dentinogenesis imperfecta occurs in a racial segregate in Maryland and is due to mutations in DSPP?
Shields Type III
132
Type __ collagen is associated with Type I and may regulate the assembly of heterotypic fibers.
V
133
What is the primary component of the glycoproteins in the basal lamina?
laminin
134
Mutations in COL6A are associated with what disease?
Bethlem myopathy
135
What chaperone protein binds to the disulfide-bonded collagen trimers and helps complete the formation of the triple helix in collagen biosynthesis?
Hsp47
136
Why are proline and hydroxyproline located on the outside of the collagen helices?
because they have the bulkiest side chains and cannot fit in the middle
137
What, typically, are X and Y in the collagenous domain of gly-X-Y?
```
X = proline
Y = hydroxyproline
```
138
In gene nomenclature, where is the collagen type noted?
COL2A1
at the 2
139
____ dentinogenesis imperfecta (III, IV) is not associated with OI and is due to mutations in DSPP.
Shields Type II
140
What are all of the fibrillar collagens (major and minor)?
I, II, III, V, XI, XXIV, XXVII
141
What does PDI do in the biosynthesis of collagen?
facilitates the bonding of cysteine residues at the nucleation point
142
A mutation in COL18 can lead to ____ syndrome, which can cause retinal detachment.
Knobloch
143
What region of the oral cavity is composed of collagen fibers in a connective tissue or stromal matrix?
lamina propria beneath the oral epithelium
144
____ OI is where abnormal collagen molecules are incorporated together with normal collagen molecules, but few or no normal collagen trimers are produced.
Type II
145
What assists in the correct trimerization and folding of collagen?
many enzymes and molecular chaperones
146
Why does scurvy lead to major issues with collagen integrity?
because scurvy occurs when there is a vitamin C deficiency; vitamin C is a critical cofactor in the hydroxylation step of collagen biosynthesis; no vitamin C = no cofactor = collagen biosynthesis shuts down
147
What facilitates the crosslinking of lysines between collagen fibrils?
5 lysyl oxidases
148
What does Type VII collagen form that interacts with the Type I collagen in the stroma and Type IV collagen and laminin in the basement membrane?
anchoring fibrils
149
What reduces the tensile strength of fibrils and increases tissue fragility?
inhibition of crosslinking
150
Which tissue has an extracellular matrix that is more abundant than the cells themselves?
connective tissue
151
What type of non-fibrillar collagen is highly expressed in the hypertrophic cartilage of growth plates?
Type IX
152
Are COL1A1 and COL1A2 the only genes that can cause OI?
NO - up to 15 genes have been known to cause OI
153
What would a functional null allele do to the COL1A1 and COL12A genes?
no protein would be produced from ONE of the alleles
154
Is the banding in fibrillar collagen lightly or darkly stained in the regions where there are gaps between the collagen fibers?
dark
155
Type __ fibers surround enamel rods and may play a role in attaching enamel to underlying dentin.
VII
156
___ form a hydrated gel in which fibrous proteins embed and resist compression and allow diffusion of nutrients.
GAGs
157
Which type of OI is caused only by a mutation in COL1A1?
Type I
158
The proteolytic processing of procollagen occurs before the formation of tropocollagen and is a _____ modification.
post-translational
159
Which type of EDS leads to the fragility and rupture of arteries?
vascular EDS
160
In specialized tissues, what is the extracellular matrix secreted by?
fibroblast-related cells (osteoblasts, chondrocytes, odontoblasts)
161
What are stroma?
cells embedded in matrix
162
___ and ___ are proteins that are both involved in the folding processes of collagen.
SERPINH1; FKBP10
163
____ fibers are calcified into cementum/bone on one end and are free at the other end to hold the free gingiva against the tooth.
Dentinogingival/Alveogingival
164
What are the 6 genes that encode Type IV collagen chains?
COL4A1 - COL4A6
165
___ different collagens have been identified. They are encoded by up to how many different genes?
28; 42
166
___ dentinogenesis imperfecta occurs in families with OI due to mutations in COL1A1 or COL1A2.
Type I
167
What are the 3 major fibrillar collagens?
I, II, and III
168
Fibrillar collagens assemble into polymeric, rod-like structures called ____.
collagen fibrils
169
Which fibers of the periodontal; ligament are located within the furcation of the roots?
interradicular fibers
170
What type of collagen is important in anchoring the epidermis to the underlying dermis?
Type VII
171
What does a collagenous domain require the presence of?
presence of glycine every 3rd amino acid
172
___ is a type of EDS caused by a mutation in ADAMTS2.
Dermatosparaxis
173
Which fibers of the periodontal ligament are found at the crest of the periodontal ligament, nearest the neck of the tooth?
alveolar crest fibers
174
What categories are the collagens divided into?
fibrillar and non-fibrillar
175
What synthesizes the basal lamina?
the cells that rest on it
176
Which protein in collagen biosynthesis helps with the folding of the triple helix?
SERPINH1 (Hsp47)
177
What are collagen molecules characterized by structurally?
long, stiff triple-stranded helical structure with 3 alpha-chains wound around each other in a superhelix
178
Which fibers of the periodontal ligament are located at the apex of the root?
periapical fibers
179
Which types of EDS are caused by mutations in genes involved in the collagen biosynthetic pathway?
kyphoscoliosis
| dermatosparaxis
180
What does collagen in the PDL attach to?
attaches cementum layer of tooth root to the alveolar bone
181
What component of ECM accounts for the controlled elasticity of a tissue?
fibrillin-1 (microfibrils)
182
In ____ collagens, the triple-helical domains are shorter and interrupted by non-collagenous sequences.
non-fibrillar
183
Collagen, elastin, fibrillin, fibronectin, vitronectin, and laminin are all ____ proteins.
fibrous
184
Which type of collagen is needed for adhering the basal lamina to the underlying stroma/epithelial tissues?
Type VII (7)
185
Why are many diseases with mutations in extracellular matrix proteins inherited in a dominant fashion?
because many of these ECM proteins form polymeric structures, so just one messed up fibril can affect the entire polymeric structure
186
What two enzymes must act in order for collagen to be converted into tropocollagen for fibril formation to occur?
ADAMTS2,3,14 and BMP-1/tolloid proteinases
187
How many genes encode type II collagen?
1 because it is a homotrimer
188
___ fibers encircle the tooth.
Circumferential
189
Which protein in collagen biosynthesis is responsible for N-propeptide cleavage in collagen biosynthesis?
ADAMTS2
190
What is the tertiary structure of collagen?
there is NOT one
191
Which condition is associated with abnormal collagen biosynthesis due to a nutritional deficiency in vitamin C?
scurvy
192
Which type of non-fibrillar collagen is a key component of anchoring fibrils that attach epithelia to the underlying connective tissue?
Type VIII
193
What is the Type IV alpha-3 chain important in?
glomerular basement membrane
194
Tendons have ECM that ____.
has a rope-like organization of collagen to give tensile strength in one direction
195
What is the principal type of collagen found in the ECM of tendons, bones, ligaments, the PDL, dentin, fascia, and skin?
Type I collagen
196
Collagens arranged in concentric weaves would be found in ___.
bone
197
What component of ECM accounts for the strength, hardness, and brittleness of the tissue?
mineral (hydroxyapatite)
198
What type of substance contains collagen embedded in polysaccharide ground substance of hyaluronan and proteoglycans/glycosaminoglycans?
stromal matrix
199
The hydroxylation of what two amino acid bases in collagen biosynthesis occurs in humans but is rare in other animal proteins?
prolines and lysines
200
What is the use of bisphosphonates associated with?
potential osteonecrosis of the jaw
201
Which protein in collagen biosynthesis assists with protein folding?
FKBP10
202
What happens when hydroxylation is stalled in collagen biosynthesis due to vitamin C?
unfolded procollagen is retained in the ER and degraded and cannot renew the connective tissue matrix AKA deficient collagen assembly
203
What are the long polysaccharides called that consist of repeating disaccharide units often covalently linked to proteins in the form of proteoglycans?
glycosaminoglycans (GAGs)
204
What is the purpose of oxytalan fibers?
the fibrillin within them allow for elasticity for tooth movement
205
Which protein of the prolyl hydroxlation complex is required for hydroxylation in collagen biosynthesis and mutations of it may cause recessive OI?
CRTAP
206
What structures contain proteoglycan-rich specialized connective tissue?
cartilage
207
What are the functions of extracellular matrix in bone?
- support and locomotion
- calcium homeostasis
- protect brain, organs
208
Collagens undergo extensive post-translational modifications in the ___ prior to the triple helix formation.
ER
209
What is the most severe type of chondroplasia?
achondrogenesis type II or hypochondrogenesis
210
What are the functions of extracellular matrix in teeth?
- provides strength/structure to tooth
| - resists shear and compression forces
211
Which fibers of the periodontal ligament are horizontally positioned in the middle of the root?
horizontal fibers
212
Which type of OI is the most severe (perinatal lethal)?
Type II
213
What do prolyl hydroxylases and lysyl hydroxylases do?
hydroxylates selected prolines and lysines for the synthesis of procollagens
214
___ fibers run between the teeth.
Transseptal
215
What are utilized in tissues according to their desired properties, such as regulation of assembly proteins, binding of growth factors and regulation of mineralization?
other ECM components
216
What is the secondary structure of collagen?
extended left-handed helix
217
What are some examples of mutations that can occur that result in Type I OI?
- allelic deletion
- promoter/enhancer mutations
- splicing mutations
- premature termination
218
Are COL1A1 and COL1A2 associated with all 4 types of OI?
YES
219
What component of the prolyl hydroxylation complex actually hydroxylates the collagen alpha chain?
prolyl-3-hydroxylase (LEPRE1)
220
____ is a hereditary disease of dentin where patients present with brown teeth that wear easily, bulbous crowns, narrow roots, small pulp chambers, and often experience splitting of the enamel.
Dentiogenesis imperfecta
221
What is the most abundant amino acid found in collagen fibers?
glycine
222
Prolyl hydroxylases and lysyl hydroxylase require what as a cofactor?
vitamin C
223
What are the roles of extracellular matrix in the regulation of cell function?
signaling
growth
differentiation
224
What are the characteristics of Ehlers Danlos syndrome?
- fragility of soft connective tissues
- issues with skin, joints, ligaments
- joint hyperlaxity
- reduced bone mass (osteopenia)
225
What type of fibrous proteins provide tensile strength and elasticity?
structural (collagen, elastin, fibrillin)
226
Type I OI is characterized as having ____ type I collagen.
reduced amounts of NORMAL
227
Collagen prolyl hydroxylation is carried out by a ____.
complex
228
What must the ECM of a tissue be able to respond to?
changes in the mechanical requirements (functional adaptation)
229
If a patient with OI presented with normal stature, blue sclera of the eyes, and had a history of bone fractures before the onset of puberty, what would you classify their OI as?
Type I
230
Patients with Ehlers Danlos syndrome can be particularly prone to life-threatening ___.
rupture of blood vessels
231
What type of osteogenesis imperfecta is the most common and the mildest?
Type I
232
____ contains abundant collage fibers to attach gingiva to the tooth and alveolar bone.
Gingiva
233
How does achondrogenesis type II occur? What is the mutation?
replacement of a glycine by a much bulkier amino acid
234
What type of collagen tethers the underlying connective tissue?
type VII anchoring fibrils
235
In patients with dentinogenesis imperfecta, what are some patient care precautions that need to be taken into consideration?
- tooth may lose feeling
- teeth can wear all the way down to gingiva
- need meticulous oral hygiene
- extra support of jaw for tooth extractions
