Term
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Definition
| undifferentiated cells with the capacity to differentiate into various cell types. Usually of mesodermal or neural crest origin |
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Term
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Definition
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Term
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Definition
| cells of the zygote located within the zona pellucida |
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Term
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Definition
12-16 cells
zona pellucida degenerating
cells no longer totipotent
ICM and OCM formed |
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Term
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Definition
| formed when the fluid filled spaces within the morula coalesce into a single space (blastocyst cavity) |
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Term
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Definition
| former ICM, now located at one end of the blastocyst - becomes the embryo proper |
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Term
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Definition
| thin outer cell layer that lines the blastocyst cavity and the ICM - contributes to the placenta |
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Term
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Definition
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Term
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Definition
multinucleated mass of cells that have migrates from the cytotrophoblast - eventually erodes the CT of the endometrium via enzymes for implantation
secretes hCG |
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Term
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Definition
| located between the cytotrophoblast and embryoblast |
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Term
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Definition
| tall, columnar cells underlying amniotic cavity - continuous with amnion |
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Term
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Definition
| cuboidal cells underlying the blastocyst cavity - continuous with exocoelomic membrane |
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Term
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Definition
| formed from the epiblast and hypoblast and lies btw the amniotic cavity and primitive yolk sac |
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Term
| by which day is the entire conceptus embedded in the endometrium? |
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Definition
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Term
| by which day is the blastocyst attached to the wall of the endometrium |
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Definition
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Term
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Definition
(extraembryonic coelom)
surrounds the amniotic cavity and yolk sac except in the region of the connecting stalk |
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Term
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Definition
| between the trophoblast and embryo proper |
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Term
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Definition
| formed by migrating hypoblast cells |
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Term
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Definition
| process by which the 3 definitive germ layers of the embryo are formed (begins with the formation of the primitive streak and the invagination of the epiblast cells within the streak) |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| skeleto-muscular system, vessels, CT, etc |
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Term
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Definition
thickened band of epiblast cells
develops specialized regions (node & pit at cranial end, groove at midline) |
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Term
| what are the 2 things that invaginating epiblast cells do? |
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Definition
1. replace the hypoblast layer, forming definitive endoderm
2. migrate between epiblast and hypoblast to form a 3rd layer, intraembryonic mesoderm |
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Term
| what happens to the primitive streak after the 4th week? |
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Definition
| it becomes less active and eventually disappears |
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Term
| primitive streak cells migrate to all areas except where? |
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Definition
| the prechordal plate/oropharyngeal membrane and the cloacal membrane (no mesoderm needed because these will evetually become holes) |
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Term
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Definition
| solid cylinder of mesoderm that extends cranially from the primitive node to the prechordal plate |
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Term
| functions of the notochord? |
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Definition
the vertebral column forms around the notochord (remnants present within the nucleus pulposis)
induces overlying ectoderm to form the neural plate (future CNS) |
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Term
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Definition
| arise from lateral cells of the neural plate that are not included in the neural tube |
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Term
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Definition
due to overgrowth of brain regions
moves septum transversum, heart, and mouth ventrally
creates rostral portion of gut |
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Term
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Definition
due to rapidly growing caudal cord
properly positions the future anus
brings components of the umbilical cord into alignment |
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Term
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Definition
right and left edges of embryonic disc are rolled laterally to create a cylinder
severely restricts communication between the extra and intraembryonic coeloms |
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Term
| when are the pharyngeal arches visible? |
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Definition
arches 1-4 visible externally after the 4th week
arch 5 is rudimentary in humans
arch 6 is not visible, but structures are present within the human that are derived from the 6th arch |
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Term
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Definition
mandibular arch
develops lateral to the patent stomodeum (primitive mouth)
develops a maxillary and a mandibular prominence for jaw formation |
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Term
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Definition
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Term
| what are the contents of the mesenchyme of a typical pharyngeal arch? |
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Definition
an aortic arch
a piece of cartilage
muscular tissue
a specific cranial nerve |
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Term
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Definition
arch 1 -- CN V (V2 and V3)
arch 2 -- VII
arch 3 -- IX
arch 4 -- X (superior laryngeal branch)
arch 6 -- X (recurrent laryngeal branch) |
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Term
|
Definition
lined externally with a single layer of ectoderm and internally with a single layer of endoderm
internally connected to share a continuous mesenchyme |
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Term
| pharyngeal grooves/clefts |
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Definition
| invaginations between arches on external surface |
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Term
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Definition
| invaginations between arches on internal surface |
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Term
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Definition
meckels cartilage
dorsal = malleus and incus
intermediate = associated middle ear structures
ventral = primordium of mandible |
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Term
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Definition
reichert's cartilage
dorsal = stapes
intermediate = styloid process/ligament
ventral = hyoid bone (less horn/upper body) |
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Term
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Definition
| forms greater horn and lower body of the hyoid bone |
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Term
| cartilage of arches 4 & 6 |
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Definition
| give rise to cartilages of the larynx |
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Term
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Definition
outer = tubotympanic recess
inner = tympanic cavity
narrow inner = eustachian tube) |
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Term
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Definition
| fossa for palatine tonsils |
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Term
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Definition
upper = inferior parathyroids
lower = thymus gland |
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Term
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Definition
upper = superior parathyroids
lower = ultimobranchial body of the thyroid (C cells) |
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Term
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Definition
| 1st arch forms a median swelling (tuberculum impar) |
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Term
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Definition
| lateral lingual swellings on either side of tuberculum impar, derived from PA 1 too |
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Term
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Definition
| swelling behind the tuberculum impar, derived from PA 2 |
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Term
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Definition
| swelling behind the copula, derived from PA 3 & 4 |
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Term
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Definition
| malformation of frenulum leaving tongue anchored to the floor of the mouth |
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Term
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Definition
| failure of lateral swellings to merge completely |
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Term
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Definition
| enlarged or reduced sized tongue due to abnormal prolif of mesenchyme within prominences |
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Term
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Definition
| single swelling located anterior to the stomodeum, derived from mesenchyme |
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Term
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Definition
| components of PAs, lie lateral to stomodeum and below the frontonasal prominence |
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Term
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Definition
| posterior components of PA 1, posterior border of stomodeum |
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Term
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Definition
| bilateral ectodermal thickenings on lateral sides of frontonasal prominence |
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Term
| development of primary palate |
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Definition
| develops from deep portions of the intermaxillary segment of the merged medial nasal prominences |
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Term
| development of the secondary palate |
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Definition
doesn't begin until the 6th week
formed from 2 lateral palatine processes that extend from the lateral surface of the maxillary prominence |
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Term
| what is the site of the fusion of primary and secondary palates called? |
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Definition
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Term
|
Definition
merging- requires continuous mesenchyme between 2 areas, the groove between 2 areas is smoothed out during this process
fusion - bringing together of 2 completely separate tissues via prolif (no continuous mesenchyme) |
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Term
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Definition
| located where mucosa is not ecposed to forces of mastication, such as lining of lips, cheeks, soft palate, alveolar mucosa, undersurface of tongue and floor of mouth |
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Term
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Definition
| located where mucosa is exposed to forces of mastication, such as gingiva and hard palate |
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Term
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Definition
| located on dorsum of tongue where it forms various papillae, some of which possess taste buds |
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Term
| characteristics of lining mucosa |
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Definition
stratified squamous non-keratinized epithelium
LP - highly vascularized, moveable
SM present |
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Term
| characteristics of masticatory mucosa |
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Definition
ortho or parakeratinized epithelium
LP - thick, dense CT
attaches to underlying bony periosteum either directly or through SM
not very moveable |
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Term
| characteristics of specialized mucosa |
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Definition
thick ortho or parakeratinized epithelium
LP - long papillae bound directly to surrounding tongue muscles |
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Term
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Definition
most numerous
cover ant 2/3 of tongue
cone shaped and covered with keratinized epithelium
aids compressing and breaking up food pressed against hard palate |
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Term
|
Definition
less numerous than filiform
scattered throughout ant 2/3
mushroom shaped, covered in either non-keratinized or lightly keratinized epithelium
possess taste buds on superior surface |
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Term
|
Definition
8-12 located just anterior to sulcus terminalis
covered by keratinized epithelium superiorly and non-keratinized laterally |
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Term
|
Definition
between labial mucosa and lip
skin - stratified squamous keratinized
vermillion border - thin, ortho or parakeratinized w/ no hair follicles or sweat glands
labial mucosa - lining mucosa with some salivary glands |
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Term
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Definition
| junction where alveolar mucosa (lining) meets gingival mucosa (masticatory) covering attached gingiva |
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Term
|
Definition
thicker, non-keratinized epithelium
LP - loose CT with elastic fibers that extend into SM |
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Term
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Definition
keratinized or parakeratinized epithelium
LP - dense CT collagen bundles that attach to periosteum, no SM |
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Term
| tooth germ consists of... |
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Definition
enamel organ (ectoderm)
dental papilla (ectomesenchyme)
dental sac/follicle (ectomesenchyme) |
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Term
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Definition
| epithelial thickenings in the regions of the future dental arches |
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Term
| dentin mineralization via globular areas |
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Definition
globular areas fuse into a heterogeneous mass with hypomineralized interglobular dentin surrounding
usually seen in the crowns in the cirumpulpal dentin |
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Term
| dentin mineralization via linear front |
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Definition
small islands of predentin become mineralized, fuse and from a continuous calcified layer
usually occurs in teeth that have already erupted
slower than globular |
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Term
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Definition
| bulk of dentin - surrounds and lies outside the dentinal tubule |
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Term
|
Definition
deposited with age within the tubule
more highly mineralized than intertubular dentin |
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Term
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Definition
first formed, peripheral layer adj to enamel
contains bundles of large, branching collagen fibrils that are oriented differently from the fibrils in the rest of dentin |
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Term
|
Definition
main portion, formed later
extends between mantle dentin and pulp chamber |
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Term
| incremental lines of von ebner |
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Definition
lines at right angels to dentinal tubules
indicate growth of dentin each day - inward toward pulp and downward toward root |
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Term
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Definition
accentuated incremental lines caused by alterations in the process of mineralization (physiologic or pathogenic)
hypocalcified bands |
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Term
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Definition
thin layer of dentin adjacent to cementum in root
caused by looping pattern of the tubules
only in root |
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Term
| where is dentin most sensitive? |
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Definition
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Term
|
Definition
formed before root formation is completed
composed of mantle dentin and the first portion of circumpulpal dentin |
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Term
|
Definition
laid down after root formation and is always circumpulpal
deposited much slower than primary
usually fewer tubules, but thicker than primary |
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Term
| reparative/tertiary dentin |
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Definition
hard tissue formed to seal off areas of dentin that have been injured
produced by damaged or newly differentiated odontoblasts |
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Term
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Definition
| lie on surface of cementum and produce organic matrix |
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Term
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Definition
| cementoblasts that have surrounded themselves with cementum (lie in lacunae and have processes in canaliculi) |
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Term
|
Definition
located in PDL and resorb cementum during ortho
may develop from cementocytes or monocytes |
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Term
|
Definition
50-55% of organic matrix
composed of collagen and ground substance |
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Term
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Definition
| extrinsic collagen fibers of the periodontal ligament that become embedded in the cementum as the cementum grows outward |
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Term
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Definition
thin layer on the upper part of root and often absent from apical portion of root
contains no cementocytes, but is covered with cementoblasts and cementoid |
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Term
|
Definition
located in apical 1/3 of root
covered by cementoid and cementoblasts with cementocytes distributed irregularly |
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Term
|
Definition
calcified bodies located on or in cementum or in PDL
forms due to remnants of epithelial root sheaths |
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Term
|
Definition
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Term
|
Definition
| attached to cementum by outward growth of cementum |
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Term
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Definition
| surrounded by cementum as it grows outward |
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Term
|
Definition
following root dentin formation, cells of the dental sac come into contact with root dentin and differentiate into cementoblasts that secrete cementoid
collagen fibers of PDL embed in cementoid (Sharpy's fibers)
cells trapped by cementoid become cemntocytes
mineralization of ground substance = deposition of hydroxyapatite crystals |
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Term
|
Definition
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Term
|
Definition
pulp in root canals
continuous with periodontal CT at apical foramen |
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Term
|
Definition
loose CT - odontoblasts, fibroblasts, undifferentiated mesebchymal cells, white blood cells
vessels, nerves |
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Term
| odontoblastic zone of pulp |
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Definition
| single layer of odontoblasts located in periphery of pulp adj to dentin |
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Term
| cell free zone of Weil in pulp |
|
Definition
present in coronal pulp
consists of CT, matrix, capillaries, nerves |
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Term
|
Definition
| fibroblasts and cells that are progenitors for odontoblasts |
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Term
|
Definition
major portion of pulp
plexus of nerves adj to cell rich zone |
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Term
|
Definition
composed of dentin surrounded by odontoblasts
rare in occurrence - usually in radicular pulp |
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Term
|
Definition
concentric calcifications around dead cells or blood thrombi
lack dentin, tubules, and odontoblasts |
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Term
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Definition
| irregularly shaped calcifications usually surrounding collagen fibers |
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Term
| components of the periodontium |
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Definition
cementum
periodontal ligament
alveolar bone proper
lamina propria of gingiva (gingival ligament) |
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Term
| development of periodontium |
|
Definition
develops from neural crest mesenchyme (ectomesenchyme) of dental sac
as cementum and ABP develop, fibers of PDL become embedded in these tissues (sharpy's fibers) |
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Term
|
Definition
fibrous connective tissue:
fibroblasts, osteoblasts/clasts, cementoblasts/clasts, epithelial cell rests of Malassez, defense cells |
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Term
|
Definition
| usually wider cervically and apically and thinner in the middle (0.15-0.4mm) |
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Term
|
Definition
suspends tooth in socket
resorbs and reforms cementum and ABP
supplys alveolus and cementum with nutrients
assists in movement of tooth (ortho) |
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Term
| dentogingival group of gingival ligament |
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Definition
most numerous
extend from cervical cementum to lamina propria |
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Term
| alveologingival group of gingival ligament |
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Definition
| arise from alveolar crest and radiate into the lamina propria |
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Term
| circular group of gingival ligament |
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Definition
| forms a band around the neck of the tooth |
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Term
| dentoperiosteal group of gingival ligament |
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Definition
| originate in cementum and run apically over alveolar crest to insert on alveolar crest or muscles of the vestible |
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Term
| interdental or transseptal ligament |
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Definition
| originate from cementum , pass over the alveolar crest, and insert on the cementum of an adj tooth |
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Term
| alveolar crest collagen fiber bundles |
|
Definition
| run downward and outward btw cementum just below the CEJ and alveolar crest |
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Term
| horizontal collagen fiber bundles |
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Definition
| just apical to alveolar crest fiber, run at right angles to long axis of tooth from cementum to ABP |
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|
Term
| oblique collagen fiber bundles |
|
Definition
most numerous
run from cementum in oblique directon to insert on bone coronally |
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Term
| apical collagen fiber bundles |
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Definition
| run from the cementum around apex to the bone |
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Term
| interradicular collagen fiber bundles |
|
Definition
only in multirooted teeth
run from cementum into bone forming the crest of the interradicular septum |
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Term
|
Definition
located on buccal and lingual surfaces
forms outer and inner plates of the alveolar processes
continuous with and surrounds ABP |
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Term
|
Definition
cancellous bone between the cortical plates and the ABP
usually filled with yellow rather than red marrow |
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Term
| interdental/interradicular septa |
|
Definition
| both composed of cancellous cone covered by ABP |
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Term
|
Definition
condyle of mandible
glenoid fossa
articular disc
2 synovial cavities
articular capsule |
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Term
|
Definition
intramembranous formation
dense fibrous CT covering - thin over fossa and thick over eminence |
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Term
|
Definition
endochondral formation
spongy bone covered with compact bone
thick dense CT covering |
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Term
|
Definition
dense, avascular CT replaced by fibrocartilage with age
divides joint into 2 synovial cavities |
|
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Term
|
Definition
| outer layer of dense CT and inner portion is a synovial membrane that produces fluid |
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Term
|
Definition
dental lamina forms
tooth buds formed by continued prolif of the epithelium along dental lamina |
|
|
Term
| when does primary dentition begin formation? |
|
Definition
|
|
Term
|
Definition
enamel organ forms
OEE forms outer portion of cap
IEE forms invaginated portion of enamel organ
dental papilla present within the enamel organ
dental sac surrounds papilla and enamel organ |
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Term
|
Definition
establishes the basic form and relative size of tooth, especially crown
lamina breaks up into islands of cells
successional lamina |
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Term
|
Definition
primordium of the enamel organ of the permanent dentition
outgrowth on lingual side of dental lamina
goes through same stages of tooth development |
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Term
|
Definition
| composed of OEE, stellate reticulum, stratum intermedium, and IEE |
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Term
|
Definition
| cuboidal cells on periphery of enamel organ |
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Term
|
Definition
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Term
|
Definition
single layer of cells bordering the dental papilla
induce cells in the dental papilla to become pre-odontoblasts |
|
|
Term
| what does the basement membrane between IEE cells and dental papilla eventually become? |
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Definition
|
|
Term
|
Definition
cells in center of enamel organ
produces GAGs to increase volume of the organ |
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Term
|
Definition
| several layers of flattened cells immediately adj to IEE |
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Term
|
Definition
begins with the apposition of dentin at tooth cusp
REE forms when OEE/stellate reticulum collapse into the stratum intermedium
enamel and dentin production begins |
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Term
|
Definition
| begins when formation of enamel and dentin reaches the future CEJ |
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|
Term
| Hertwigs epithelial root sheath |
|
Definition
develops from enamel organ near cervical loop
consists of only OEE and IEE (no enamel production)
IEE = induction of root dentin formation |
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Term
|
Definition
| an ameloblast secretes organic matrix as it moves from the DEJ toward the coronal surface forming rods (Tomes process) |
|
|
Term
|
Definition
begins immediately upon deposition of organic matrix (25-30%)
finishes during maturation stage where ameloblasts resorb some organic matrix and replace it with additional hydroxyapatite crystals (so that it is 96% mineralized) |
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Term
|
Definition
| alternating dark/light bands produced by the change in direction of adj rod groups as they pass toward the surface |
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Term
|
Definition
| rods intertwine more irregularly near the dentin in the region of cusps or incisal edges |
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Term
|
Definition
| transverse dark lines along length of enamel rods that demarcate daily growth patterns of a particular rod |
|
|
Term
| incremental lines of Retzius |
|
Definition
| reflect variations in structure and mineralization that occur during more extended periods of enamel growth |
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Term
|
Definition
| grooves on the enamel surface where striae of Retzius reach the surface of the enamel |
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Term
|
Definition
extend from DEJ about 1/5 of the way through the enamel
result when organic matrix was not resorbed adequately |
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Term
|
Definition
thin bands that extend through enamel and sometimes dentin
develop in planes of tension produced by dimensional changes as the tissue matures |
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|
Term
|
Definition
| projections of odontoblast processes that cross the DEJ into enamel |
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