Fichas
OCB02-1007-Mechanisms of Post-Natal Growth
Fichas del conjunto (29)
- 1What are the 3 regions of the craniofacial complex?1. cranial vault
2. lower jaw
3. upper jaw - 2In a baby's head, how many fontanelles are there? What is the ratio of the cranial vault:face?6 fontanelles
8:1 - 3Rank the following in terms of growth rate from fastest to slowest: 1. Skull, eyes, inner/middle ear, brain 2. Face, body 3. Cranial baseSkull, eyes, inner/middle ear, brain>Cranial base (NEURAL rate first then somatic)>Face, body
- 4What endochondral bones are present in the skull?Cranial base
Pharyngeal arch cartilage
Octic/nasal capsule - 5What is the difference between endochondral and membrane bone in terms of formation and function?Endochondral bones form in cartiledge first then ossify; are STRUCTURAL
Membrane bone comes straight from cells going into osteoblasts; forms secondary cartilage in response to TENSION/STRESS - 6Where is membrane bone located in the skull?Clavicle outside of head
- 7What cells give rise to the face?Cranial neural crest cells
- 8What cells give rise to the cranial vault/base?Mesoderm cells under neural crest
- 9What three types of primary cartilage growth occurs post natally in terms of 1. Basi-occipital/basi-sphenoid and nasal septum 2. Growth plates 3. Remodelling1. Synchrondosis between basi-occipital/basi-sphenoid and nasal septum
2. Growth plates undergoing interstitial (at ends) growth
3. Remodelling with appositional (width) growth - 10What three types of membrane bone growth occurs in the facial/cranial vault?1. Growth of sutures
2. Surface deposition/remodelling by osteoblast/clasts
3. Secondary cartilage growth eg. Condylar cartilage - 11What are the steps of cranial vault development?1. Mesenchymal cells become osteoblasts that produce matrix
2. Bones grow/ossify, meet at sutures
3. Sutural cells ossify and grow
4. Displacement, brain pushes sutures apart
5. At the same time, remodelling as bones flatten to accommodate brain - 12What causes Microcephaly (brain defect)?Zika virus
- 13What do the prechordal, hypophyseal and parachordal cartilaginous precursors fuse to become?The occipital, sphenoid and ethmoid bone
- 14What are the 2 mechanisms of cranial base growth?Cartilaginous growth at growth plates
- Intersphenoid synchondrosis (birth)
- Speno-ethmoidal synchondrosis (3-5 yrs)
- Spheno-occipital synchondrosis (12-16 yrs)
Remodelling that moves cranial base and face anteriorly and inferiorly - 15What form of growth is present in the sphenooccipital synchondrosis? What are the 4 zones? What cell is responsible?Bidirectional endochondral growth with progenitor zone, proliferative zone, hypertrophic zone, and replacement bone
Chrondocytes - 16What are 3 consequences of cranial base defects?1. No space for 3rd molars
2. Underdevelopment (eg. achondroplasia, Down's syndrome)
3. Class 3 occlusion - 17What type of cartiledge is Meckel's Cartilage, and what does it do?Transient endochondral cartilage
Supports the downward growth of the lower jaw - 18What are the steps of mandible development?1. Meckle's cartilage forms
2. Membrane bone ossifies around M. cartilage
3. M. cartilage disintegrates
4. Secondary cartilage forms in periosteum of membrane bone
5. Remodelling moves condylar/coronoid process back, lengthens mandible - 19What does Meckle's cartilage give rise to?Malleus/Incus bone
Perichondrium of sphenomandibular/sphenomalleolar ligaments - 20What 3 types of secondary cartilage are present?1. Condylar cartilage
2. Coronoid (disappear by birth)
3. Symphysial (unites mandible) - 21What are unique features of secondary cartiladge?1. Much more disorganised
2. Growth is quicker
3. Prechondrocytes not surrounded in matrix
4. fibrocartilage VS. hyaline - 22What are the 5 layers at the secondary cartilage growth plate?1. Periosteum (undifferentiated)
2. Prechondroblastic
3. Chondroblastic
4. Hypertrophic
5. Zone of bone formation - 23What are the 4 mechanisms of mandible growth?Remodelling at anterior border of ramus
Growth of secondary cartilage
- Condylar cartilage
- Symphysial cartilage
- Coronoid cartilage
Size difference between deciduous molars and their successors - premolar
Forward movement of teeth through alveolar bone - 24What is the only endochondral bone in the upper jaw?The Nasal septum
- 25What are the 4 mechanisms of growth in the Maxilla bone?Sutural growth and remodelling of maxilla and development of maxilla sinus
Endochondral growth of septal cartilage (nasal septum/ethmoid)
Addition of bone at tuberosity that makes room for permanent molars
- Develops in alveolar bulbs at back of maxilla
Teeth move forward as deposition on outer surface and resorption on inner surface increases size of maxilla bone - 26Is the cranial base endochondral or membrane bone?Endochondral Bone
- 27Is the cranial vault endochondral or membrane bone?Membrane Bone
- 28What are the 2 mechanisms of cranial vault growth?Suture Growth and remodelling
- 29What are 2 limitations in growth of the upper face?1. At year 1, metopic suture unites+great wings/body of sphenoid ossifies limiting width
2. At year 3 Cribiform plate of ethmoid unites
Información
- Descripción
- endochondral and intramembranous ossification+which bones develop in cartilage vs membrane four methods of bone growth, sutural growth, endochondral growth(growth plate) and growth by bone remodelling/secondary cartilage. key differences between primary/ secondary cartilage Define the three basic regions of the skull: cranial vault, cranial base,, face features of the skull and face at birth Shape of bones changes postnatally i.e. mandible and maxilla cont.
- Creado por
- Evian Chai
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