OCB02-1007-Mechanisms of Post-Natal Growth

Descrição

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.
Evian Chai
FlashCards por Evian Chai, atualizado more than 1 year ago
Evian Chai
Criado por Evian Chai mais de 4 anos atrás
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Resumo de Recurso

Questão Responda
What are the 3 regions of the craniofacial complex? 1. cranial vault 2. lower jaw 3. upper jaw
In a baby's head, how many fontanelles are there? What is the ratio of the cranial vault:face? 6 fontanelles 8:1
Rank the following in terms of growth rate from fastest to slowest: 1. Skull, eyes, inner/middle ear, brain 2. Face, body 3. Cranial base Skull, eyes, inner/middle ear, brain>Cranial base (NEURAL rate first then somatic)>Face, body
What endochondral bones are present in the skull? Cranial base Pharyngeal arch cartilage Octic/nasal capsule
What 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
Where is membrane bone located in the skull? Clavicle outside of head
What cells give rise to the face? Cranial neural crest cells
What cells give rise to the cranial vault/base? Mesoderm cells under neural crest
What three types of primary cartilage growth occurs post natally in terms of 1. Basi-occipital/basi-sphenoid and nasal septum 2. Growth plates 3. Remodelling 1. Synchrondosis between basi-occipital/basi-sphenoid and nasal septum 2. Growth plates undergoing interstitial (at ends) growth 3. Remodelling with appositional (width) growth
What 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
What 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
What causes Microcephaly (brain defect)? Zika virus
What do the prechordal, hypophyseal and parachordal cartilaginous precursors fuse to become? The occipital, sphenoid and ethmoid bone
What 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
What 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
What are 3 consequences of cranial base defects? 1. No space for 3rd molars 2. Underdevelopment (eg. achondroplasia, Down's syndrome) 3. Class 3 occlusion
What type of cartiledge is Meckel's Cartilage, and what does it do? Transient endochondral cartilage Supports the downward growth of the lower jaw
What 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
What does Meckle's cartilage give rise to? Malleus/Incus bone Perichondrium of sphenomandibular/sphenomalleolar ligaments
What 3 types of secondary cartilage are present? 1. Condylar cartilage 2. Coronoid (disappear by birth) 3. Symphysial (unites mandible)
What are unique features of secondary cartiladge? 1. Much more disorganised 2. Growth is quicker 3. Prechondrocytes not surrounded in matrix 4. fibrocartilage VS. hyaline
What are the 5 layers at the secondary cartilage growth plate? 1. Periosteum (undifferentiated) 2. Prechondroblastic 3. Chondroblastic 4. Hypertrophic 5. Zone of bone formation
What 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
What is the only endochondral bone in the upper jaw? The Nasal septum
What 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
Is the cranial base endochondral or membrane bone? Endochondral Bone
Is the cranial vault endochondral or membrane bone? Membrane Bone
What are the 2 mechanisms of cranial vault growth? Suture Growth and remodelling
What 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

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