nature of craniofacial growth Flashcards
an increase in the number of cells
Hyperplasia
an increase in the the size of cells
Hypertrophy
whays cellular growth appears
Secreteion of extracellular material
Hypertrophy
Hyperplasiaa
what leads to the critical distinction between soft and hard tissues
Calcification of the extracellular material
is cartilage hard of soft tissue
Soft
how does soft tissue growth occur
Combo of hyperplaisa and hypertrophy
result of the growth of soft tissue
interstitial growth (growth inside tissue)
what can also accompnay interstitial growth
secretion of extracellular material
endochondral ossification
Cartilage is growing then replaced by bone
what type of growth is a characteristic of uncalcified cartilage
Interstitial growth
can interstitial growth occur in hard tissue
No, and growth can only occur at the surface and not in the calcified mass
hos does growth of hard tissue occur
direct addition in free surface, by cells of the periosteum
replacement of soft tissue
what does the growing in endochondrial ossification
cartilage grows, followed by replacement by bone
how does Endochondral ossification occur on long bones
bone formation on surface of cartilage
Invasion of blood vessel to hollow out center
ingrowth of B.V> lead to ossification center in the catilaginous caps
band of cartilage remains, to form a diaphysis and epiphyses
bands of cartilage in a long bone
Epiphyseal plates
how does a bone grow longer
Endochondral replacement
how does a bone grow wider
Direction formation of new bone
what does bone widening
PEriostem
can bone change in calcifed masses
Yes, due to osteocytes
why remodel the inner surface of bone
adapting to mechanical stresses
makes calcium and phosphate ion exchanges with blood
where does calcium and phosophate exchange occur
around the periosteal surface and havershian systems
what is a haversian system
osteocytes surroudning a blood vessel
2 parts of the canium
cranial vault
Cranial base
parts of the face
Maso-maxillary complex
Mandibular
how is the cranial vault ade
directly with no endochondral bone formation.
Uses just the periosteum
the connective tissue in between the bones fo the cranial valt
Fontanelles
Roll of Fontanelles
Considerable deformation at brith so you can give birth to the baby
how is the cranial base formed
Endochondrial ossification
the cartilage of the cranial base
Chondocranium
when does the chondocranium occur
About 8 weeks in utero
when does ossification begin in the chondocranium
week 12 at the same time as intramembranous bone formation of the cranial vault
how does growth occur at the cranial base
at the lateral edges of the strucutres via synchondroses
important synchondroses for growth
Spheno-occipital, inter-sphenoid
spheno-ethmoidal
difference in synchondrosis and suture
Synchondrosis is cartilage with maturing cartialge extending outsward in both directions
suture is only periosteum and connective tissue
how does maxillary growth occur
Sutures and surface remodeling
what indirectly affects the naso maxillary complex
endochondrial growth of the cranial base
how does the maxillar grow
Along the sutures
what are the posterior and superior sutures of the maxilla idea for
Downward and forward repositioning of the maxilla
where is bone added to allow molars to erupt
The tuberoscity
how is the anterior of the maxilla changed as it grows down and forward
remodeled and removed
why does it look like the maxilla moves more downward than forward
surface remodeling opposes forward translation but adds to the downward
how does the mandible develop
Associated with cartilage but doesn’t really replace it
where does bone formation begin in the mandible
LAteral to Meckel’s cartialge and spreads posterior without using cartilage
fuses early at the midline
where is the cartialge in the MAndible
At the TMJ, not derived from meckel’s cartilage, but late in life
how does the manible grow
Some at the condylar cartilage, rest by direct surface apposition and remodeling
where does most of the growth of the mandible occure
Posteriorly, via appositional growth, pushing the mandible forward
how is the ramus remodeled
Bone is added to the posterior and removed from the anterior
how is the mandible wided
REmodeling of the ramus
how does the alveolar bone grow
Grows upward along with the teeth
why must new alveolar bone form
Keep the teeth from growing right out of the mandibule
