Development L1 - Craniofacial growth and functional appliances

Question 1

Embryology development begins once fertilisation has occured.

the fetilised egg will travel down to the uterine tube into the uterus

the fertilised egg will attach on to the uterus wall and devlop in to a ………..?

Answer 1

the fertilised egg during its first week of fertilisation is called a Blastula/Blastocyst

Question 2

a process called CASTRULATION forms the blastula in to three germ layers.

what is the name of these three germ layers and their function

Answer 2

the 3 germ layers are called:

ECTODERM: will become skin and nervous system tissue.

MESODERM: will become muscles, kidneys and other connective tissue.

ENDODERM: will become the primative gut.

Question 3

NEURAL CREST CELLS from the back of the foetus will move to the front of the foetus, and contribute to making the facial prominences/process.

where are neural crest cells derived from

Answer 3

neural crest cells are derived from the ectoderm.

Question 4

Draw and annotate a foetus at 4 weeks in development

Answer 4

Question 5

what are the names of the facial process/prominence that make up the face

Answer 5

1. Frontonasal process
2. Maxillary process
3. Medial nasal process
4. Lateral nasal process
5. Mandibular process

Question 6

there are 6 pharangyeal arches during embryo development. of those 6 pharangyeal arches, which are responsible for the development of the face.

Answer 6

1st and 2nd pharangyeal arches.

Question 7

The 1st pharangyeal arch contains which facial process

Answer 7

Maxillary and Mandibular process

Question 8

studies suggest that a malfunction in the TCOF1 gene, results in the development of the condition called TREACHER COLLINS SYNDROME.

explain the following

the protein produced by TCOF1 and its function.

Answer 8

Studies suggest that the protein TREACLE (produced by the TCOF1 gene) is involved in the production of a molecule called ribosomal RNA (rRNA).

rRNA helps assemble protein building blocks (amino acids) into functional proteins which play an important role in early development of bones and other tissues of the face.

Question 9

name this condition and the absence of the protein responsible for it.

Answer 9

treacher collins syndrome

protein responsible for the condition is the absence of the protein TREACLE.

Question 10

name the condition shown and what is believed to be responsible for the condition

Answer 10

condition - HEMIFACIAL MICROSOMIA

hemifacial microsomia is the condition that affects the development of the lower half of the face

it is believed hemifacial microsomia is caused by the disturbances in the blood supply in the first and second pharangyeal arches, in the first 6 - 8 weeks in embryo development

Question 11

orofacial clefting is broken down to two complications, what are they?

Answer 11

complication of the cleft lip

complication of the cleft palate

complication of the cleft lip and palate

Question 12

during weeks 6-10 in embryo devlopment.

the medial nasal process fuse togther along with the maxillary process, this fusing allows for the devlopment of what?

Answer 12

upper lip

Question 13

which process is responsible for the lower lip?

1. frontonasal process
2. maxillary process
3. medial nasal process
4. lateral nasal process
5. mandibular process

Answer 13

5. mandibular process

Question 14

the development of the palate is initiated by the maxillary process.

how is the palate developed and at which week.

Answer 14

The development of the secondary palate commences in the sixth week of human embryonic development. It is characterised by the formation of two palatal shelves through the proliferation of the maxillary prominences

Question 15

A disturbance of development on the maxillary prominence during week 6 - 10 can result in which complications

Answer 15

cleft lip or palate or both.

Question 16

at which week in embryo development would you see the fusing of the primary palate with the secondary palate.

Answer 16

at week 10 would you see the complete fusion between primary and secondary palate

Question 17

growth velocity is broken down to 3 phases what are they

Answer 17

infentile

juvenile

adultescent

Question 18

the cranial complex is broken down to 4 complexes, what are they?

Answer 18

cranial vault

cranial base

nasomaxillary complex

mandible

Question 19

the cranial vault comprises of skeletal sutures and periosteal activity

how are the skeletal sutures formed

Answer 19

skeletal sutures are formed by intra-membranous ossification

Question 20

the fontanelles are comprised of membranous connective tissue, which allow the skull to flex, allowing the childs head to pass through the birth canal.

complications in the fontanelles can lead to the following pathology

1. hydrocephaly
2. microcephaly
3. craniosynostosis

briefly describe these conditions

Answer 20

1. hydrocephaly: fluid accumulates in the brain, enlarging the head and sometimes causing brain damage
2. microcephaly: where the circumference of the head is smaller than normal, can be caused by genetic abnormalities, drugs or viruses that are exposed to the foetus during pregnancy
3. craniosynostosis: birth defect where one or more cranial sutures close before the babys brain has fully formed. causing the brain to grow in abnormal shapes.

Question 21

the cranial base undergoes endochondral ossification. there are synchondrosis located in the cranial base.

what is a synchondrosis

Answer 21

a synchrondosis is a joint in which the bones are bound by a hyaline crtilage

Question 22

the centres of ossification are on either side of synchondrosis, here the cartilage grows rapidly and then replaced by bone.

the centres of ossification are known as what?

and what controls the centres of ossification

Answer 22

the centres of ossification are known as primary growth centres and are under genetic and epigenetic control

Question 23

the nasomaxillary complex comprises of the maxilla, nasal and zyogomatic. what type of ossification occurs in this complex

Answer 23

intramembranous ossification.

there is no synchondrosis in the nasomaxillary complex. thus no endochondral ossification

Question 24

the nasomaxillary complex is responsible for SURFACE REMODELING.

surface remodeling works by the function of osteoblasts and osteoclasts.

explain how surface remodeling works in development.

Answer 24

during development, PARATHYROID HORMONE stimulate the release of calcium and phosphate to SERUM. this stimulates the osteoblasts.

osteoblast in return stimulate osteclasts.

osteoclast a large multinucleate bone cell which absorbs bone tissue by enzymes allows osteoblast a single nucleated cell to deposit osteoid, which is made of bone collagen.

Question 25

if there is a low serum calcium level, how do osteoclast react and what complication may this cause?

Answer 25

low serum calcium levels would trigger the osteoclast to resorb bone to maintain a serum calcium level. due to the removal of bone and the failure to deposit new bone. the bone becomes brittle and succeptible to fractures.

Question 26

the development of the mandible occurs through both endochondral and intramembranous ossification.

explain how meckels cartilage is responsible for the devlopment of the mandible.

Answer 26

meckels cartilage is derived during week 6 of embryp development.

the meckels cartilage houses the inferior alveolar nerve. and where the inferior alveolar birfurcates to form the mental and incisive branch sits the ossification centre.

this centre is the initial site of osteogenesis

intramembranous ossification occurs rapidly and teh mandible is produced by the 8th - 12th week

the meckels cartilage retreats to form the condylar and coronoid cartilage.

which drive endochondral ossification of the mandible during post natal development.

Question 27

endochondral bone formation is seen in 3 areas of the mandible, where are they.

Answer 27

the meckels cartilage retreats to specific areas of the mandible, where endochondral ossification can take place.

these specific areas are the

condylar process

coronoid process

mental process

Question 28

during which week in INTRAUTERINE LIFE (IU) where mesenchymal condensation forms the attachment of both coronoid and condylar process

Answer 28

week 10.

Question 29

there are 5 component parts of the mandible which is responsible for the post natal development of the mandible. name the 5 parts.

Answer 29

coronoid process

condylar process

alveolar process

angular process

mental process

Question 30

the condyle is unique that it has a hinge and slide function and also more sensitive to change in mechanical conditions compared to any other cartilage.

how might this affect the mandible in development with functional appliances.

Answer 30

mechanical stimulation of the condyle can stimulate endochondral ossification along with remodeling which helps manipulate the mandible.

Question 31

in acromegaly how is the condylar cartilage affected?

Answer 31

in acromegaly the condylar cartilage responds to the hormonal stimulation, resulting in the growth of the mandible, compared to maxilla.

Question 32

how are functional appliances are used to correct problems of the mouth and specifically which problem.

Answer 32

functional appliances are used to correct CLASS II problems and are done so by the stimulation of the condylar process.