What does the frontonasal process surround?
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The forebrain.
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What does the frontonasal process surround?
The forebrain.
What structures are formed by the frontonasal process?
The forehead and the dorsum apex of the nose.
What is the origin of ectomesenchyme?
It originates from the neural crest.
What do neural crest cells give rise to in the cephalic region?
Bones of the face, skull, parts of teeth, and periodontal ligament.
What is the role of neural tube folds in the formation of ectomesenchyme?
They contribute to the formation of neural crest cells.
What is orthognathic surgery?
Orthognathic surgery is a corrective jaw surgery that straightens or realigns the jaw.
What is another name for Hemifacial Microsomia?
It is also called oral-mandibular-auricular syndrome or otomandibular dysostosis.
Why do we study growth?
To understand development, monitor health, and identify abnormalities.
What is the main characteristic of Hemifacial Microsomia?
The lower half of one side of the face is underdeveloped and does not grow normally.
Why is early detection crucial?
To enable timely management and intervention.
What is palatal expansion?
A dental procedure to widen the upper jaw.
What is the consequence of missing the growth window and having a posterior crossbite as an adult?
Orthognathic surgery may be required to correct the posterior crossbite.
What are the types of cleft lip and palate?
(A) incomplete unilateral cleft of the lip, (B) unilateral cleft of the lip, alveolus, and palate, (C) bilateral cleft of the lip, alveolus, and palate, (D) isolated (median) cleft palate.
What is a posterior crossbite?
A condition where the top back teeth bite inside the bottom back teeth.
What is included in Hemifacial Microsomia?
Underdevelopment of the ear.
What are the three main features of Pierre Robin Sequence?
Cleft palate, retrognathia, and glossoptosis.
What is the function of the median nasal process?
To smooth the median furrow in the midline.
What is the downward direction of growth known as?
Vertical growth.
When does the secondary palate close in females?
1 week later than in males.
How many facial processes are involved in forming the human face?
What is the incidence ratio of cleft lip/palate as a congenital anomaly?
Approximately 1:750.
What is a teratogen?
Any agent that can produce a congenital anomaly or raise the incidence of an anomaly in the population.
What is pre-palatal expansion?
A procedure to widen the upper jaw before the growth of the midpalatal suture is complete.
What happens when the medial nasal prominences merge in the midline?
They smooth the median furrow.
What is glossoptosis in Pierre Robin Sequence?
It is airway obstruction caused by the backward displacement of the tongue base.
How does a cleft of the lip increase the likelihood of a cleft of the palate?
The tongue gets trapped, leading to a higher likelihood of a cleft of the palate.
What is the forward direction of growth known as?
Anteroposterior growth.
What is the topic of the study related to the human face?
Facial Processes.
What kind of treatment is required for cleft lip/palate?
Early and long-term orthodontic and surgical treatment at various growth stages.
What is hypertrophy?
Hypertrophy is the increase in the size of cells, resulting in an increase in the size of the organ or tissue.
When are the organs and parts of an embryo most sensitive to teratogenic agents?
During periods of rapid differentiation.
What is another name for Velocardiofacial syndrome?
DiGeorge Syndrome.
What is the region that will develop into the anterior two thirds of the tongue?
The first pharyngeal pouch.
What is required for the normal development of the upper lip?
Union of the medial nasal prominences and maxillary prominences.
What is post-palatal expansion?
A procedure to widen the upper jaw after the growth of the midpalatal suture is complete.
What is the difference between microdeletion and microduplication?
Microduplication is less harmful than microdeletion because genetic material is not missing.
What does the first pharyngeal pouch between the first and second arches become?
The middle ear chamber.
What is hyperplasia?
Hyperplasia is the increase in the number of cells, resulting in an increase in the size of the organ or tissue.
What are the medical problems associated with Velocardiofacial syndrome?
Cleft palate, heart defects, decreased immune response, kidney malfunction, learning problems, speech and feeding problems.
When does the secondary palate form during gestation?
6th to 9th weeks of gestation.
At what stage of development does the union of the medial nasal prominences and maxillary prominences occur?
4 - 6 weeks.
What is a congenital anomaly?
An anomaly present at birth.
Where do olfactory placodes develop in the nose?
On the lateral aspect of the frontonasal processes.
What is a deletion in terms of genetic anomalies?
It is chromosomal breakage where a part is lost.
What are the two types of inheritance for Treacher Collins syndrome?
Autosomal dominant (TCOF1) or autosomal recessive (POLR1D).
When does the primary palate form?
During the 4th to 7th week of gestation.
What does the first pharyngeal cleft (hyomandibular) become?
The external ear canal.
What are the five facial processes that form during the 4th week of embryonic development?
Single Fronto-nasal process, Paired Maxillary processes, Paired Mandibular processes.
What happens in an inversion anomaly?
A segment of chromosome is reversed, leading to a high risk of offspring abnormalities.
What change occurs in the position of palatal shelves during palate formation?
They change from vertical to horizontal position and fuse.
What are the characteristic facial features of Velocardiofacial syndrome?
Long face, flattened cheeks, large nose.
What is the result of cleft formation?
A deficiency of tissue.
What percentage of congenital anomalies have an unknown cause?
50 - 60%.
What are visceral arches?
Structures formed in the early embryo that give rise to various head and neck structures.
What is Cri du chat syndrome associated with?
Loss of the small arm of Chromosome 5.
When does the formation of the secondary palate occur?
During the 6th - 9th week in utero.
At what stage of human gestation do the olfactory placodes line the nasal pits?
Fifth week.
What are the physical features associated with Treacher Collins syndrome?
Downward-slanting eyes, micrognathia, conductive hearing loss, underdeveloped zygomatic bones, drooping part of the lateral lower eyelids, and malformed or absent ears.
What does the second (hyoid) pharyngeal arch contain?
Reichert's cartilage and cranial facial (VII) nerve.
What merges to form the primary palate?
Two maxillary swellings and two medial nasal swellings.
What occurs in isochromosomes?
The centromere divides transversely instead of longitudinally.
What surrounds the embryo's primitive mouth during facial development?
The five facial processes.
Why must the tongue descend during palate formation?
To allow for proper fusion of the palatal shelves.
When does cleft lip occur?
When an epithelial bridge fails.
What percentage of congenital anomalies have a genetic cause?
33% (85% of all known causes).
What do visceral arches develop into?
They give rise to structures such as the jaw, middle ear, and throat.
Which syndrome is associated with a small segment of Chromosome 22?
DiGeorge syndrome.
What is Palatal Expansion?
A process to widen the upper jaw to create more space in the mouth.
How do the palatine processes align during secondary palate formation?
Bilaterally and vertically.
What is the intelligence level of individuals with Treacher Collins syndrome?
Normal intelligence.
What components form the inter-maxillary segment?
Labial Component (Philtrum), Maxilla Component (Alveolus + 4 Incisors), Palatal Component (Triangular Primary Palate).
What is the specific content of the first (mandibular) arch?
Meckel's cartilage, cranial trigeminal (V) nerve, and aortic arch.
What are the adult face and its embryonic derivative of?
The five facial processes.
What percentage of congenital anomalies have an environmental cause?
7 - 10%.
Where do clefts of primary palate occur?
Anterior to the incisive foramen.
What are microdeletion and microduplication in genetic anomalies?
They are very small interstitial and terminal deletions.
How many visceral arches are there in the early embryo?
There are six visceral arches in the early embryo.
What is Surgically Assisted Palatal Expansion (SARPE)?
A procedure to widen the upper jaw using a surgical approach in children or adolescents.
What forms around the nasal pits in the fifth week of human gestation?
Medial and lateral nasal prominences.
In what direction do the palatal shelves ascend and fuse during secondary palate formation?
In an A -> P (anterior to posterior) direction.
What is the majority cause of aborted fetuses?
Genetic abnormality.
What is the frontonasal process involved in?
Developing the front part of the face.
What is the term for different phenotype based on parental origin in genetic anomalies?
Genetic Imprinting.
Where do clefts of secondary palate occur?
Posterior to the incisive foramen.
Where do the lateral nasal prominences develop into?
Sides (alae) of the nose.
What is Sutural Opening?
The opening of the suture between the bones of the skull to allow for palatal expansion.
What is initially interposed between the secondary palatal shelves?
The tongue.
What facial part is formed by the frontonasal prominence?
Forehead and the dorsum apex of the nose.
What does the median nasal process contribute to?
Formation of the middle part of the nose.
What does the medial nasal prominences develop into?
Nasal septum and philtrum.
What does the lateral nasal process contribute to?
Formation of the sides of the nose.
When does the primary palate form?
During the 4th - 7th weeks of development.
Which facial region is formed by the maxillary prominences?
Upper cheek region and most of the upper lip.
What is the maxillary process involved in?
Developing the upper jaw and the secondary palate.
What fuses at the midline to form the primary palate?
Medial nasal prominences.
What facial features are developed from the mandibular prominences?
Chin, lower lip, and lower cheek regions.
What does the mandibular process contribute to?
Formation of the lower jaw.
What is polyploidy?
The condition of having more than two complete sets of chromosomes.
What components fuse to form the intermaxillary segment?
Maxillary Prominence and Medial Nasal Prominences.
What does the labial component of the intermaxillary segment form?
Philtrum.
What is triploidy?
The presence of an extra set of chromosomes, resulting in a total of 69 chromosomes.
What is tetraploidy?
The presence of two extra sets of chromosomes, resulting in a total of 92 chromosomes.
What does the maxillary component of the intermaxillary segment form?
Alveolus and 4 incisors.
What does the palatal component of the intermaxillary segment form?
Triangular primary palate.
What is translocation in genetics?
The transfer of a piece of one chromosome to a nonhomologous chromosome.
What is reciprocal translocation?
When chromosomes exchange pieces during translocation.
Where do the soft palate muscles insert in palatal clefts?
On the posterior margin of the remaining hard palate rather than the midline raphe.
What percentage of Trisomy 21 patients have the extra chromosome attached to another chromosome?
3-4%.
What percentage of individuals with palatal clefts have supernumerary teeth?
20%.
What percentage of individuals with palatal clefts have dystrophic teeth?
30%.
What is the percentage risk of non-syndromic inheritance of cleft lip with or without cleft palate when one parent is affected?
2%.
What percentage of individuals with palatal clefts have missing teeth?
50%.
What is the percentage risk of non-syndromic inheritance of cleft lip with or without cleft palate when one sibling is affected?
4%.
What is the percentage risk of non-syndromic inheritance of cleft lip with or without cleft palate when two siblings are affected?
9%.
What is the percentage risk of non-syndromic inheritance of cleft lip with or without cleft palate when one parent and one sibling are affected?
15%.
What is the percentage risk of non-syndromic inheritance of cleft palate when one parent is affected?
7%.
What is the percentage risk of non-syndromic inheritance of cleft palate when one sibling is affected?
2%.
What is the percentage risk of non-syndromic inheritance of cleft palate when two siblings are affected?
10%.
What is the typical cause of numerical abnormalities?
Nondisjunction, the failure of genes to disjoin during meiosis or mitosis.
What is the percentage risk of non-syndromic inheritance of cleft palate when one parent and one sibling are affected?
17%.
What is aneuploidy?
A deviation from the human diploid number of 46 chromosomes (44 as autosome pairs and 2 sex chromosomes).
What does monosomy refer to?
Having one missing chromosome of a pair.
Why do typically embryos with more than one extra chromosome or less than one chromosome not survive?
Because 99%+ abort.
What is mosaicism?
The presence of two or more populations of cells with different genotypes in one individual.
How does mosaicism affect patients with the same disorder?
It leads to a milder phenotype than in non-mosaic patients with the same disorder.
