Physiology of Articulatory and Resonance System Part 2 Flashcards
Nasal Cavities
-nasal placodes become nasal pits
-pits form primordial nasal sacs: develop nasal cavities
Nasal Choanae
-Joining oral and nasal cavities
-forms posterior nasal cavity opening into nasopharynx
-superior/middle/inferior conchae develop on lateral walls
-superior nasal cavity ectoderm becomes olfactory epithelium
-some cells differentiate into olfactory sensation
-axons become olfactory nerve
Palatal Development
-Palatogenesis: development of primary (premaxilla) and secondary palate
-secondary palate: occurs between 6-12 weeks
-critical period: 6-9 weeks, most prone to development of cleft of secondary palate
Primary Palate
-anterior structures
-lip, premaxilla, and alveolar ridge
-precursor to premaxilla
-hold 4 maxillary incisors
-develops from median palatine process
Secondary Palate
-posterior structures
-hard and soft palate
-develops from left and right palatine processes
-begins developing late 6th through 8th weeks
-incisive foramen boundary between palates
Primary and Secondary Palates Fusion
-initially processes on either side of tongue, projecting inferiorly
-7th through 8th week: mandible elongates, oral cavity increases in size, tongue lowers, allows elevation to horizontal position as grows medially
-processes fuse by 8th week
-primary and secondary palates fuse at incisive foramen and intermaxillary suture
Mandibular Development
-weeks 5-8
-mandible develops from Meckel cartilage within 1st pharyngeal arch
-Meckel cartilaginous bars from left and right halves
-fuse at midline mentum
Dentition Development: Week 6
-labiogingival lamina forms on mandible and maxilla surface
-dental lamina form in gingiva
Dentition Development: Week 8
-10 tooth buds develop in mesenchyme of mandible and maxilla
-developing into 20 deciduous teeth by 12th week
Dentition Development: Weeks 10-16
-enamel, dentin, vasculature develops
Dentition Development: Weeks 14-18
-calcification occurs start root ends crown
-starts incisors ends molars
Dentition Development: Weeks 16-18
-permanent teeth buds emerge
Dentition Development: Weeks 18-20
-molars begin development
General Craniofacial Growth: Not linear
-structures grow at different rates
-remodeling and resorption
-remodeling: adding tissue to structures
-resorption: absorbing tissue already present
Craniofacial Development: Generally
-all grow rapidly between 3 and 5 years
-craniocaudal growth
-braincase exhibits earliest and rapid growth
-followed by structure below it
-facial growth: inferior and anterior
Respiration and Mastication Structures
-rapid growth before 5 years: includes pharynx and larynx
-puberty
-marked face elongation
-increased dental alveoli depth
-anterior growth
-20 yrs of age: end of growth period
Postnatal Development: Mandible Growth
-growth center in condyle
-most rapid growth during adolescence (7 years): complete by 15-18 years
-deciduous dentition replaced by permanent teeth starting 6 years of age
Postnatal Development: Mandible Growth (Ramus)
-ramus grows and moves mandible forward and down
-most rapid growth 1-2 years of age
-mature dimension by 12 years of age
Postnatal Development: Mandible Growth (Symphysis)
-ossifies by 1 year
-most ossification between 6-9 months
Postnatal Development: Mandible Growth (Corpus)
-rapid growth 3-5 years
-bone added to posterior and inferior parts
Maxilla Growth: Inferiorly and Anteriorly
-face deepens and lengthens
-grows from remodeling: posterior bones pushes face forward
-most vertical growth between 7-15 years
-rapid growth first 5 years
-significant acceleration during puberty: broadens as cranium enlarges
Maxilla Growth: Dentition
-deciduous dentition replaced by permanent teeth starting 6 years ago
Maxilla Growth: Hard Palate
-vaulted at birth
-oral surface bone added and resorbed on nasal surface
-produces downward movement
-premaxilla and palatal processes remodeled: labial bone reabsorption, disposition of bone on lingual side
-experience with chewing hard food helps spread upper dental arch and lowers vault
Maxilla Growth: Sutures
-intermaxillary and premaxillary sutures complete 2 years of age (start prenatally)
Maxilla Growth: Anterior and Posterior
-face anterior-posterior growth first 5 years incorporate lengthening of hard palate
Velum Growth
-rapid change in first 2 years
-length increases: 28 mm at 4 yrs to 33.4 mm at 21 years
-velopharyngeal port increases with craniofacial growth: 18 mm at 4 yrs to 22 mm at 21 years
-posterior nasal spine to posterior pharyngeal wall
-males larger velums and velopharyngeal port
Vocal Tract Growth: Nasopharynx
-enlarges and more angle compared to oropharynx
Vocal Tract Growth: Oral Cavity
-grows, tongue descends, and oropharyngeal space increases
-oral cavity adult size between 7-18 years`
Vocal Tract Growth: Vocal Tract Length
-lips to vocal folds distance increases from 6-8cm at birth grows to 15-18cm in adulthood
-pharyngeal and oral cavities contribute to increase during first 4 years: after 4 years greatest change due pharynx growth
-growth spurt between 5-12 years
-significant determinant of vowel first formant
-vocal tract volume also influences formants
Aging Articulatory System: Changes in structure and function due tissue changes
-bone loss and resorption
-dental enamel loss
-sarcopenia
Aging Articulatory System: Mandibular bone loss produces weakened dental arch
-more vulnerable to fracture
Skull Bone Remodeling:
-Head increases in length and circumference
-decrease in alveolar depth results in no net increase skull size
-mandible length decreases and maxilla flattens out
-oral and pharyngeal spaces increases in length and volume: general vocal tract length remains equivalent
Soft Tissue Changes: Epidermis
-loses collagen
Soft Tissue Changes: Muscle
-atrophy due to sarcopenia produces reduced articulator strength and endurance
-tongue strength and velum function decrease
Soft Tissue Changes
-no significant impact on speech production with some swallowing difficulty
-rate of speech production decreases with age
