5th class Flashcards
What are the 3 possibilities for growth?
Hypertrophy
Hyperplasia
Secretion of extracellular matrix
Increase in the size of individual cells, which is referred to as ________
hypertrophy.
Increase in the number of the cells, which is called ________
hyperplasia
Increase in the number of the cells, which is called ________
hyperplasia
_______ is the process of bone formation by
osteoblasts.
Ossification (osteogenesis)
Ossification begins approximately ___ weeks after fertilization
in an embryo.
6 weeks
Before 6 weeks when ossification has begun, the embryonic skeleton
consists entirely of ________ and _________
fibrous membranes and hyaline cartilage.
The development of bone from:
•Fibrous membranes is called ________
intramembranous ossification.
The development of bone from:
•Hyaline cartilage is called ___________
endochondral ossification.
________ is the process of bone development from fibrous membranes.
It is the direct deposition of bone on thin layers of connective tissue and is characteristic of the bones on the top of the skull.
Intramembranous ossification
What 3 locations are mentioned in the lecture that undergo intramembranous ossification?
Mandible, Maxilla, and Top of skull
What is the progression of cell types in intramembranous ossification?
Mesenchyme cells -> Osteoprogenitor cells -> osteoblasts
•Endochondral ossification is the process of bone development from
_________
hyaline cartilage.
Where does endochondral ossification occur in the body?
Everywhere but the top of skull, Mandible, and maxilla
The craniofacial complex can be divided into what 4 areas that grow
rather differently?
Cranial vault
Cranial base
Nasomaxillary complex
Mandible
•The bones that cover the upper and outer surface of the brain.
Cranial Vault:
•The bony floor under the brain, which also is the dividing line between the
cranium and the face.
Cranial Base:
•Made up of the nose, maxilla and associated bones.
Nasomaxillary Complex:
Calvaria grows by ______ ossification.
intramembranous ossification
What 3 factors are are involved in calvarium growth?
- Suture growth.
- Remodeling/surface apposition. (after 4yrs)
- Brain expansion.
Bones of the cranial base are formed initially in
cartilage and are later transformed by _______ ossification to bone.
endochondral
ossification
As ossification proceeds, bands of cartilage called ________
remain between the center of ossification.
synchondroses
_______ are bands of primary cartilage that persist between
ossification centres.
Synchondrosis
Synchodrosis have ____ epiphyseal plates
2-sided
How many Synchondroses are there in the cranial base?
What are their names?
3
Inter-sphenoid
Spheno-ethomoidal
Spheno-occipital
When does the inter-sphenoid synchondrosis fuse?
At birth
When does the spheno-ethmoidal synchondrosis fuse?
6 yrs
When does the Spheno-occipital synchondrosis fuse?
17-20 yrs
Postnatal growth occurs in what 2 ways?
At sutures
By surface remodeling
By maxilla growing via sutures and surface remodeling, the maxilla moves in what 2 directions
relative to the cranium and cranial base?
downward and forward
As growth of surrounding soft tissues translates the maxilla downward and forward, opening up space at its \_\_\_\_\_\_ and \_\_\_\_\_\_\_\_ sutural attachments, new bone is added on both sides of the sutures.
superior and posterior
Where does growth occur most in mandible?
Cartilage covering mandibular condyles
Is the chin of the mandible a site of significant growth?
No
Outside of the chin and condyles, how does the mandible grow in the other areas?
Remodeling/Apposition
Where does the growth via hyperplasia, hypertrophy, and endochondral replacement occur in the mandible?
Condyle and posterior surface of ramus
Removal of bone from anterior surface and
deposition of bone on the posterior surface of
ramus make the mandible ______
longer.
In relation to the cranial base, the chin of the mandible moves in what 2 directions?
Down and forward
In what direction does the mandibular ramus move?
Posteriorly
The correct concept is that the mandible is _______
downward and forward and _____ upward and
backward in response to this translation, maintaining its
contact with the skull.
translated; grows
Due to the vast movement of the ramus over time, does the mandible grow more by endochondral replacement or appostion?
Apposition
Which synchondrosis is the most important clinically in ortho?
Shpeno-occipital