Exam 2 Flashcards
Odontogensis
Process of tooth development
Oral Epithelium
Comes from Ectoderm lining stomodeum made of 2 arches w/ horseshoe shape (ectoderm gives rise to Epithelium)
Mesenchyme cells come from
Neural crest cells
Found underlying epithelium
Tooth development stages #1
- Initiation @ 6th week of prenatal developmental
-INDUCTION initiates Oral Epithelium to proliferate into Mesenchyme (10 areas on top and 10 areas on bottom)
*lack of initiation = tooth won’t start developing and tooth will be absent
As initiation starts the Epithelium proliferates deep into the Mesenchyme
to form a strand of tissue called Dental Lamina becoming a bud (tooth bud)
Ectomesenchyme is
Coming from ectoderm
Tooth Development Stage 2
Bud Stage (PROLIFERATION) @8th week
Bud forms due to growth of Dental Lamina penetrating Mesenchyme
Bud continues to proliferate. differentiation and Morphogenesis turns bud into cap
Tooth development stage 3
Cap Stage (proliferation, differentiation, Morphogenesis) @ 9th-10th week
Mesenchymal cells inside and outside cap proliferating and condensing to form Tooth Germ (future tooth)
Cap continues to proliferate deeper and elongates into bell
Tooth Germ
Made up by
ENAMEL ORGAN
-future enamel (cap lookalike)
DENTAL PAPILLA
-future dentin and pulp (inside cap)
DENTAL SAC
-future periodontium=cementum, periodontal ligament, alveolar bone (outside cap)
Tooth Development Stage 4
Bell stage (@ various times of development)
Proliferation, DIFFERENTIATION, Morphogenesis
4 different cell types found within Enamel organ (inner to outer)
Inner enamel epithelium
Stratum intermedium
Stellate reticulum
Outer enamel epithelium
Inner enamel epithelium (4th bell stage)
Differentiates into future Ameloblasts (cells responsible for enamel formation)
Stratum intermedium - compressed cuboidal
Stellate reticulum - star shape
Both layers of enamel organ help support future production of enamel
Outer enamel epithelium
Protective barrier for enamel organ
Provides nutrients to Ameloblasts to support their activity
Bell stage ( tooth development stage 4)
Dental papilla
Dental papilla cell types
Dental papilla
-cells align along basement membrane and state elongating
Cell types:
outer cells of dental papilla
Inner cells of dp
(Bell stage)
Outer cells of dental papilla
Inner cells of dental papilla
Odontoblasts are doing what during bell stage?
Differentiates into odontoblasts (cells responsible for dentin formation)
Differentiates into Fibroblasts (major cells for pulp tissue)
Odontoblasts: begin their production early on to lay down the Dentin Matrix then calcify it
Also move inward towards the center of the Dental papilla
Tooth development stage 5
Name of stage, week #
Matrix is? formed by?
Ameloblasts form? How?
What happens when ameloblast finish their job?
Apposition Stage (@various times of development)
induction and proliferation
Matrix (organic materials-proteins, carbs, lipids) formed by Ameloblasts
-Calcified later from tapered end of columnar like cells (Tomes process)
Ameloblasts form enamel completely starting at cusp tip/Incisal edge to outward (opposition growth=layer after layer overlapping) becoming shorter and all 4 layers of enamel organ become compressed to form cuticle placed on newly developed crown (reduced enamel epithelium)
Ameloblasts finish their job and we gone forever! Enamel can’t be regenerated
Tooth development stage 6
Name and week #
What happens to dental tissue
Maturation stage (@ various time of development)
Dental tissue fully mineralized and calcified
Once basement membrane disintegrates and dentin matrix is laid down what is established
Dentoenamel junction (DEJ)
Disintegration of basement membrane induces ___ ______ to differentiate into ____ who will lay down ____ ____. They _____ enamel matrix and ____ ____
Pre-ameloblasts to differentiate into ameloblasts who will lay down enamel matrix, calcify it and move outward
Odontoblasts
Ameloblasts
Inward
Outward
Dentin is always ____ than enamel
Why?
Thicker
Because of production of dentin starts earlier than the production of enamel
When odontoblasts finish their job they ? Making ?
Stay at pulp wall making new dentin as long as tooth is alive
Cervical loop
Responsible for root development
Most cervical rim of enamel organ made up of 2 layers
-inner enamel epithelium
-outer enamel epithelium
Hertwig epithelial root sheath proliferates deep into ___ ____
Making…
Proliferates deep into dental papilla making shape of root
-curved or straight, short or long, single or multiple
Hertwig epithelial root sheath proliferates inducing cells of dental papilla to
HERS then disintegrates and
Differentiate into odontoblasts who start making dentin in root area
Newly formed root dentin in contact with cells of dental sac
Induction of dental sac causes it to differentiate into _____ who align themselves along root dentin and start making ____ ____. They ____ it and move out.
But the cementobalsts stay where ?
Cementoblasts
Cemento matrix
Calcify
On wall of cementum
Epithelial Rests of malassez
What can it do in the future ?
Remnant of disintegrated Hertwig Epithelial Root Sheath
It can proliferate in the future and become cyst found in mature periodontal ligament (periodontal cyst);
When if the tooth ready to erupt? Which happens before what?
When crown formed
Happens before root completed which can take ~ 2-4 years after tooth erupts
Reduced enamel epithelium fuses with ____. Enzyme starts disintegrating the fused tissue. This is all know as _____?
Fuses with oral epithelium and enzyme starts disintegrating fused tissue (teething)
Discomfort and inflammation
Permanent tooth starts initiating tooth development when primary tooth in ____ stage.
Permanent tooth has its dental Lamina _____ to primary tooth for succedaneous teeth
Cap
Lingually
Nonsuccedaneous teeth develop _____ like primary teeth
Normally
Nasmyth membrane
Residue that may form on newly erupted teeth
Leaving teeth extrinsically stained (can go away from brushing)
Odontoclasts
Cells responsible for root resorption
Suffixes for cell
-blasts
-clasts
-cytes
Forming cells
Resorbing cells
Maintains cells
Osteoclasts
Bony portion being resorbed
Prenatal development
Fertilization to birth
Postnatal development
Continuing development after baby born (neonatal)
Fertilization
Jointing of sex cells/gametes
-spermocyte, male
-secondary oocyte, female
Zygote
Goes through ____ until reaching ___ ___ __ _____
Fertilized egg
Goes through mitosis until reaching back wall of uterus
Ovulation happens at about day
Secondary oocyte survives
Sperm survives
When should you target to get pregnant
14
Several hours
About 48 hours
Day 12-16
Male and female gametes contain ____ ____ ____
By going though ___
Haploid chromosome number (23) by going through meiosis
Meiosis
Cell division resulting in daughter cells having haploid chromosome number (23)
Diploid chromosome number needed to create human
46
Preimplantation period
Days?
Zygote goes through ___ and becomes___ that then becomes ___
7-10 days
Zygote goes through mitosis becoming morula (solid ball of cells) ->blastocyst which differentiates into embryoblast (bunch of cells)
Embryonic period
2-8 weeks
Embryonic period
Induction
Proliferation
Differentiation
Morphogenesis
Maturation
Group of cells induce other group of cells to take different path
Controlled cellular growth
Change in cell to become distinct structurally and functionally
Cell takes different shape or form
Attainment of adult function and size
Embryonic period
Embyroblast differentiate into 2 layers ?
Epiblast layer and hypoblast layer
Epiblast layer continues to proliferate and forms
Depression where cells migrate in between 2 layers forming Trilaminar Disc
-with inside cells called Mesoderm cells (from migratory cells from epiblast)
Epiblast layer to ____
Hypoblast layer to ____
Ectoderm
Endoderm
Trilaminar embryonic disc
Ectoderm- epithelium-outer covering
Mesoderm-everything in middle expect oral pharyngeal and cloacal membrane
Endoderm-lining of digestive tract
@4th week embryo folds by pushing endoderm into ____ and ____ in between
Ectoderm with mesoderm in between
Oral pharyngeal and cloacal membrane are Temporary and will disintegrate forming
Only ___ and ____. No
Stomodeum And end of digestive tract
Only ectoderm and endoderm no mesoderm
Mesenchyme from neural crest cells is
Connective tissue in head and neck area
Ectoderm lining stomodeum differentiate into
Epithelium lining primitive mouth
Head develops from 5 processes
2 Mandibular
2 maxillary
1 Frontonasal
Mandibular processes form
Form mandible With Mandibular teeth
Lower lip
(Lower third of face)
Maxillary processes form
(Middle third of face)
Side of upper lip
Cheeks
Secondary palate
Posterior portion of maxilla
Maxillary canines
Posterior teeth
Zygomatic bones
temporal bones
Frontonasal processes form
Forehead
Bridge of nose
Primary palate
Nasal septum
All structures of medial nasal processes, nasal placodes, nasal pits
(Upper third of face)
Maxillary and Mandibular processes fuse to form
Labial commissures
Medial nasal processes fuse together to form
Gives rise to
Middle portion of nose
Philtrum
Inter maxillary segment
Intermaxillary segment gives rise to
Primary palate
Nasal septum
Maxillary portion that Carrie’s incisors
Frontonasal process and maxillary processes fuse together to form
Upper lip
Lateral nasal process gives rise to
Ala of nose
Medial lateral and maxillary processes fuse together to form
Nostrils
Pharyngeal apparatus
Neck develops from
Made of arches groove and pouches
1st Mandibular Branchial arches
Meckels cartilage
Muscles of mastication
5th cranial, Trigeminal nerve
Frogs body of tongue
2nd hyoid arch
Reicherts cartilage
Muscles of facial expression
7th facial nerve
Forms base of tongue
3rd Branchial arch
Unnamed
Pharyngeal muscle
9th glossopharyngeal nerve
Forms base of tongue
4th and 6th Branchial arch
Unnamed
Larynx and pharynx muscle
10th vagus nerve
Forms base of tongue (4th only)
Branchial grooves
1st forms external acoustic meatus
Last 4 obliterate to give neck smooth contour
Branchial membranes
1st forms Tympanic membrane
Last 4 membranes temporary
Branchial pouches
1st form’s auditory tube and tympanic cavities
2nd forms palatine Tonsillar tissue
3rd and 4th forms thymus and parathyroid glands
Palate formed by
2 secondary palates from maxillary processes
1 primary (from Intermaxillary segment p)
2 secondary palates fuse together to from median palatine suture
Fusion of 1and 2 compete palate
-fusing between lateral incisor and canine
Tongue develops from
1st arch gives rise to 2 ____ ____ ____ and they fuse to from ____ ____ ____
_____ fuses with 2 lateral lingual swellings to from ____ ____
Lingual swellings from 1st 4 Branchial arches
1st arch gives rise to 2 lateral lingual swellings fusing together to form medial lingual sulcus
Copula fuses with 2 lateral lingual swellings to form sulcus terminals (v shape between body and base)
