Embryology and histology Exam 2 study guide, Exams of Biology

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Embryology and histology Exam 2 study

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Lying Inferior to the mandibular arch is the ________ _________ also known as the __________. - second pharyngeal arch; hyoid arch The _________ and the _________ ________ develop from the first pharyngeal pouch. - middle ear; Eustachian tube During the _____ week, the frontal area becomes the frontonasal processes. - 5th Placodes are thickened areas of epithelium, and __________ for __________ _______ organs. There are three. ________, _________, _________. - ectoderm; special sense; lens, otic, nasal Development of the face and oral cavity begins with the? In week? - stomodeum; 4th There are _____ facial process which are the centers of growth for the face: ___________ processes ___________ processes ___________ process. - 5: maxillary mandibular frontonasal All of the face and most structures of the __________ _________ come from the 1st branchial arch and frontonasal process with the exception of ________ _______ ________ which develops from the 2nd, 3rd, and 4th arches. - oral cavity; posterior 1/3 of tongue

Disintegration of the ______________ ______________ enlarges the stomodeum of the embryo and allows access between the primitive mouth and ____________. - oropharyngeal membrane; primitive pharynx The mandibular processes also fuse forming the mandibular are which is _________ to the enlarged stomodeum. - inferior The development of the _______ comes from the medial and lateral nasal processes. - nose Upper lip develops between weeks ___ ____. And forms the following processes ________ ________ ________. - 6-8; medial nasal processes ________ _________ form the philtrum right and left maxillary processes. - globular processes The ______ _______ develops between weeks 4-6. - primary palate Fusion of the medial nasal processes forms the __________ _________. - intermaxillary segment The ________ _______ develops between weeks 6-12. - secondary palate Maxillary process gives rise to two ________ ________ which fuse with the ________ ________. - palatal shelves; globular processes The final palate formation is in week? - 12 The fusion of the _____ _______ _______ and the right and left maxillary processes forms the upper lip.

• medial nasal processes

In the ______ prenatal week, the ________ ________ muscle develops around the oral pit. - 6th; orbicularis oris The upper lip is composed of a medial nasal process and 2 lateral maxillary proceses. If this does not fuse correctly, what can result? _____________________. - cleft palate/lip The __________ _____________ _____________ is the valley or cleft between the mandibular and hyoid arches or 1st and 2nd arches. - first pharyngeal groove The ______ ________, a modification of the first pharyngeal groove info the ear canal appears below the corners of the mouth. - auditory tube Six ________ _________ group around the external ear canal - auricular hillocks palatal development happens weeks? to? - 6- The palate separates the oral and? cavitites - nasal the hard palate has a? base and the soft palate has a? base - bony; muscular The tongue forms between weeks? to? - 4 to 8 _____ is the anterior portion formed by the first pharyngeal arch - body Base is the posterior portion formed by the _______, _______, ________ branchial arches. - 2,3,

The tongue is innervated by the ____, ____, ____, _____, and ______ cranial nerves. 5th is _______ 7th is ___________ 9 is _________________ 10 is _________ 12 is ________________ - 5, 7, 9, 10, 12 5- trigeminal 7- facial 9- glossopharyngeal 10- vagus 12- hypoglossal ______ _________ is a v shaped line between the body and base of the tongue. - sulcus terminalis The _______ ______ embryonic origin of the ________ gland. - foramen cecum; thyroid Posterior to the terminal sulucs, the base of the tongue form the ______ _______ on the ______ surface. - lingual tonsil; dorsal The lingual tonsil forms part of ________ _______ in the pharynx along with the _________ and ________ ________. - waldeyers ring; palatine and pharyngeal tonsils During week 7, the _______ descends in front of the trachea. - thyroid During this migration, the ______ gland remains attached to the tongue by an ________ ________ called the __________ duct. - thyroid; epithelial chord; thyroglossal

The thyroid gland develops from the _______ ________. - foramen cecum Swelling that has an opening on the surface of the neck is a _______ __________. - thyroglossal fistula ______ _______ is the most common face malformation - cleft lip ? twice as much cleft lip or cleft lip and palate - males females have a higher incidence of? - cleft palate the origin of osteoclasts are - monocytes A human possessing 2 dentitions is a - diphyodont supporting tissues of the teeth include - cementum, pdl, alveolar bone No teeth present - adontia some teeth missing - partial adontia less than 6 teeth missing - hypodontia more than 6 teeth missing - Oligodontia

ondontogenesis has a - posterior progression Teeth develop from _____ types of cells. _______ _______ cell from which form the enamel organ and _________ cells which from the dental papillla - 2; oral ectodermal; mesenchymal beginning stages of tooth development is in week - 6 how many stages of tooth development are there - 6 dental lamina becomes - deciduous teeth ____________ lamina becomes succedaneous (permanent teeth). - successional _________ lamina becomes non-succedaneous teeth, 12 ______. Accessional. - general; molars Teeth develop _______________. - anteroposteriorly 6 stages of tooth development and when they begin: ________- begins week ___ the _________ process happens here ________- begins week ___ the _________ process happens here ________ - weeks ___ to ____the _________ process happens here ________ - weeks ___ to ___ the _________ process happens here ________ - week ______ ________ - week ______ - initiation; 6; induciton bud stage; 8; proliferation cap stage; 9-10; morphogensis

bell stage; 11-12; differentiation apposition- varies maturation- varies The dental lamina _________ into buds. - proliferates In the cap stage, the epithelial cells of the dental lamina now become the ______ ______ and remain attached to the lamina. - enamel organ Mesenchymal cells form the ______ _______ which becomes the ______ ______ area. - dental lamina; pulp blue In the bell stage, the enamel organ has developed into an ______ and ______ ________ ________. - outer; inner enamel epithelium ______ become ameloblasts that form the enamel - IEE Between the inner and outer enamel epithelium are ______ ________ cells. - stellate reticulum Ondontoblasts are derived from ectomesenchymal cells which were formerly ______ _____ ___. - neural crest cells The _______ ________ _________ is the layer that is most closely associated with blood vessels. - outer enamel epithelium _____ covers the enamel organ - OEE

_____ becomes ameloblasts - IEE __________ become enamel - ameloblasts __________ makes space for developing crown to get nutrients from the OEE to the Ameloblasts. - stratum reticulum _____________ is next to the IEE and helps ameloblasts in formation of enamel - stratum intermedium Dental papilla makes ondontoblasts in the ______ _____. - peripheral area Predentin calcifies in ______ to dentin. - 24 hours Enamel is derived from _________. - ectoderm Deep to the developing oral epithelium a type of tissue called _____________ becomes the dental papilla. - ectomesenchyme What is all derived from the ectomesenchyme: _______, ________, ________, _________, _________ _____. - cementum, dentin, pulp, pdl, alveolar bone three layers that make up the tooth germ: - enamel organ, dental papilla, dental sac ______ _______which becomes the enamel covering for the outer layer of the tooth - enamel organ ______ _______ which is an inner mass of tissue that will become _______ and ______ - dental papilla; dentin and pulp

dental sac which will become the,? also known as the supporting tissues of the tooth. - periodontium The periodontium includes the _______, _____, ______ ________ - cementum, PDL, alveolar bone ______ ______and ________ ______ comes from the ectomesenchyme - dental papilla, dental sac 2 layers of the dental papilla: Outer which will become _______ and make ________ Inner which will become _______ _______ - ondontoblasts; dentin pulp tissue _____________- a protective layer for the enamel organ - outer enamel epithelium _____________- star-shaped cells that aid in enamel formation - stellate reticulum _____________- flat or cube-shaped cells that also aid in enamel formation - stratum intermedium ______________- these cells will become ameloblasts and make enamel. - inner enamel epithelium Dentinogenesis always _________ amelogenesis - precedes Preameloblasts act upon the outer cells of the dental papilla to differentiate into ____________. - ondontoblasts

________ ________ is short, conical, tapered processes that develop at the apical end of ameloblasts during the ________ _________. - tomes process; secretory stage ________ _______ is the actual secretory surface of these ameloblasts (the short, conical, tapered portion that faces the DEJ). - tomes process Tomes processes develop in the ________ _______ of ameloblast differentiation. - secretory stage Dentinal tubules are the conduit or passageway for __________ for the ondontoblasts. - nutrition The _______ _______ is the most cervical portion of the enamel organ. It is the structure that is responsible for ________ _________. - cervical loop; root development The cervical loop grows to from _________ _________ ______ _______. This serves to shape the roots and induce dentin formation in the root area. - henrtwigs epithelial root sheath HERS is comprised of the ________ and ________ ________ ________ of the enamel organ. - outer and inner epithelial layers Cementum is the layer that will develop over _______ ________. - root dentin there is no _________ formation in the roots - enamel _________ ________ _ _________are clusters of leftover cells from Hertwig's epithelial root sheath that remain in the PDL throughout life. - epithelial rests of malassez the bone between the roots of multicoated teeth are called? bone - interradicular

ne end of the PDL fibers becomes embedded in the __________ on the root surface and the other end attaches to forming ________ _______. - cementum; alveolar bone Which teeth develop from general lamina? ________ which teeth develop from successional lamina ________ - 12 molars; permanent incisors, canines, premolars Do permanent teeth generally erupt from the facial/buccal or lingual of primary teeth? ________ - lingual _______ formation and ________ formation happen in the preeruptive phase - crown and bone Root formation, movement, penetration, intra oral movement all happen in the __________ _________ ________ - prefunctional eruptive phase Occlusal wear of enamel happens in the ___________ ________ phase. - functional eruptive 3 main causes of tooth shedding/ exfoliation?

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Crown size too small for ______________ - root formation bone resorption mastication Lack of eruption is referred to as __________ and the cause can be related to fusion of the _____ _______ to the ________ or crown of a permanent tooth. - ankylosis; tooth root to bone The prefunctional eruptive phase starts with initiation of ________ ________ and ends when the teeth reach _________ _________. - root formation; occlusal contact

The first step of root formation is _____________ of the epithelial root sheath. - proliferation What could happen without an opposing tooth? - hypereruption The __________ _________ ____________ next contacts and fuses with the oral epithelium called the junctional epithelium - reduced enamel epithelium The clinical crown is the exposed crown extending from the ______ ____ to the area of ______ __________. - cusp tip; gingival attachment The _______ ________ is the entire crown from cusp tip to the CEJ. - anatomic crown _________ and ____________ remodel alveolar bone - osteoclasts; osteoblasts The presence of primary teeth roots poses a problem for the process of? for permanent teeth. - eruption The eruption of succedaneous teeth happens ________ to the primary anterior teeth and under or between the _______ of the primary molars. - lingual; roots Permanent accessional molars erupt into the _________ _______ _______ behind primary teeth - alveolar free space Reabsopriton of the root is carried out by _________ which arise from monocytes in the bloodstream. - osteoclasts

Hard tissue (root) reabsorption occurs in 2 phases. _________ phase and _________ phase. - extracellular and intracellular In the ___________ phase; osteoclasts ingest mineral fragments from the extracellular phase. - intracellular Special fibroblast cells, now considered _________, destroy remaining collagen fibers secondarily by __________. - fibroclasts; ingestion Clinically with tooth eruption,? occurs. - blanching Root completion continues after teeth have begun to function. _____ to ______ years for deciduous teeth and _____ to _____ years for permanent teeth - 1-1.5, 2- Final maturation of the ________ fibers occurs when the teeth have reached functional ___________. - PDL; occlusion Leeway space is the ____________ size difference between a primary molar and a permanent premolar.

• mesiodistal Is there greater leeway space in maxillary or mandibular? ___________ ( _____mm maxillary vs ______ mandibular) - mandibular; 1.3;3. _______ permanent teeth have no predecessor and are called ___________. - 12; nonsuccedaneous/ accessional Roots of primary teeth are shorter and ________ ________ than roots of permanent teeth. - more divergent

_______ is the hardest tissue of the body. It is brittle and subject to __________. - enamel; fractures Enamel is made up of ____% __________ material in the form of calcium hydroxyapetite crystals and __ % water and organic material. - 96; inorganic; 4 Thickness of enamel ranges from knife-edge to about ______mm thick. It is the thickest where the ________ or ________ load is heaviest. - 2.5; incisal or occlusal _______ _____ are prisms extending from the DEJ to the outer surface of the enamel. - enamel rods Enamel rods are produced by ________________. - ameloblasts One ameloblast forms the ______ ______. Two ameloblasts forms the ______, and a fourth ameloblast forms the ______. - rod head; neck; tail The surface of the enamel rod is called the _____ _________. - rod sheath The __________ of the rod is the rod sheath and the _________ is called the core. The core is most sensitive to __________________. - surface, center ? and?? appear called hunter schreger bands - light and dark bands underlying? is yellowish - dentin The repeating pattern can be seen along the axis of the tooth and extends through _________ to __________ of the thickness of enamel. - 1/2 to 1/

____________ _______ are brown lines in enamel that are circular like rings on a tree. They are also called the _______ ___ ___________. - incremental lines; striaes of retzius Those lines are the result of ___________ __________ deposition of enamel. - rhythmic recurrent Neonatal line is an accentuated __________ ________ of Rezius due to environmental and _________ changes at the time of birth. - incremental line; nutritional _________ __________ are in the surface of enamel, extending from the __________l to incisal surfaces, ________ to the enamel surface. They are ________ to the naked eye. - incremental lines; cervical; DEJ; visible Breathing cold air is a risk factor when developing ________ ________. - dental lamellae Developmental defects at the DEJ that are filled with organic material (enamelin) are ________ _________. - enamel tufts Enamel tufts extend 1/10 to 1/5 of the way from the _________ to the outer surface of the tooth. - DEJ Spindles arise at the DEJ and extend into the ________. - enamel An enamel spindle houses a small extension of a living ___________. - ondontoblasts Perikymata or _____________ _________ are the external manifestation of the _________ _____ ___________. - imbrication lines; striae of retzius Perikymata are more prominent near the _________ region on the _________ surface of the teeth. - cervical; facial

__________ enamel does not facilitate the spread of dental caries. - prismless What are the two colors (light and dark) bands extending about ½ to ⅔ of the enamel? _________ __________ ________. - hunter schreger bands Hunter- Schreger bands are visibly seen when ________ is shown on _________. - light; enamel the organic component of enamel is - enamelin