Exam 2 Flashcards by McCall S

Odontogensis

Process of tooth development

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Oral Epithelium

Comes from Ectoderm lining stomodeum made of 2 arches w/ horseshoe shape (ectoderm gives rise to Epithelium)

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Mesenchyme cells come from

Neural crest cells
Found underlying epithelium

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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)

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Ectomesenchyme is

Coming from ectoderm

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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

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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

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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)

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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

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Inner enamel epithelium (4th bell stage)

Differentiates into future Ameloblasts (cells responsible for enamel formation)

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Stratum intermedium - compressed cuboidal

Stellate reticulum - star shape

Both layers of enamel organ help support future production of enamel

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Outer enamel epithelium

Protective barrier for enamel organ

Provides nutrients to Ameloblasts to support their activity

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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

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(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

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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

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Tooth development stage 6

Name and week #
What happens to dental tissue

Maturation stage (@ various time of development)

Dental tissue fully mineralized and calcified

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Once basement membrane disintegrates and dentin matrix is laid down what is established

Dentoenamel junction (DEJ)

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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

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Odontoblasts

Ameloblasts

Inward

Outward

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Dentin is always ____ than enamel
Why?

Thicker
Because of production of dentin starts earlier than the production of enamel

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When odontoblasts finish their job they ? Making ?

Stay at pulp wall making new dentin as long as tooth is alive

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Cervical loop

Responsible for root development

Most cervical rim of enamel organ made up of 2 layers
-inner enamel epithelium
-outer enamel epithelium

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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

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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

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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

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)

Exam 2 Flashcards

(73 cards)