The three parts of the human embryo are pars cranialis, pars umbilicalis and pars caudalis.
Yes
No
The yolk sac is connected to the middle portion of the enteron of an embryo by ductus vitellinus.
The first pharyngeal arch, also called mandibular arch, forms the thyroid cartilage.
Fourth and fifth pharyngeal arches fuse to form a portion of mesopharynx.
The ossification of the mandible starts in the region of the bifurcation of mental and incisive branches of n. alveolaris inferior through the process of metaplasia in embryonic bone.
The initial stages of fetal development of the human embryo are: 1. 2. 3. 4.
Write a definition for each of the following terms: 1. Buccopharangeal membrane: A /ectoderm and endoderm/ that lies at the . 2. Pharangeal arch: . 3. Metaplasia in embryonic bone: The process of of the into
The primitive mouth /stomodeum/ is formed:
At the end of the first month of embryonic life
At the end of the third month of embryonic life
During the third month of embryonic life
During the fifth month of embryonic life
The development of the maxillofacial region of an embryo is observed at the end of the:
Second week of embryonic life
Fourth week of embryonic life
Third week of embryonic life
Fifth week of embryonic life
Stomodeum is:
The enteron of an embryo
Mesoderm
The oral pit
Ectoderm
The enteron of an embryo consists of:
a) Ectoderm
b) Endoderm
c) Mesoderm
a + b + c
The development of the pharyngeal grooves and arches is observed at the beginning of the:
First week of embryonic life
The first pharyngeal arch gives rise to the:
Thyroid cartilage
Floor of the mouth, larynx, pharynx
Salivary glands, tongue, muscles of mastication
Mandible, part of maxilla
The second pharyngeal arch gives rise to the:
Hyoid bone, apex and dorsum of the tongue
Lower jaw
The third pharyngeal arch gives rise to the:
Hyoid bone
Thyroid cartilage, root of the tongue
Muscles of mastication
The tongue starts to develop during the:
First month of embryonic life
Second month of embryonic life
Third month of embryonic life
Fourth month of embryonic life
The floor of the mouth is derived from:
First, second and third pharyngeal arches
First pharyngeal arch
First, second, third and fourth pharyngeal arches
Second and third pharyngeal arches
The hyoid bone is derived from the:
Second pharyngeal arch
Third pharyngeal arch
Fourth pharyngeal arch
The thyroid cartilage is derived from the:
The maxilla is derived from the: 1.Fifth pharyngeal arch 2.Second pharyngeal arch 3. Two maxillary processes 4. Third pharyngeal arch 5. Frontonasal process
3,5
1,2,3
3,4,5
2,3,5
The statement about the cleft lip that is correct is:
A defect due to the failure of the fusion of the maxillary and lateral nasal processes
A defect due to the failure of the fusion of the maxillary and medial nasal processes
A defect due to the failure of fusion of the palatine processes
Fill in the gaps of column A using the numbers of column B, to make the statement correct:
Column A a) Ectoderm: b) Endoderm: c) Mesoderm:
Column B 1. Inner layer 2. Middle layer 3. Outer layer
The initial stage of foetal development of an embryo, characterised by fast cell division at a geometric progression, producing a cluster of cells, is called a .
The cleft palate is a defect that permits open communication between .
The tongue is derived from the: 1. first pharyngeal arch 2. second pharyngeal arch 3. third pharyngeal arch 4. fourth pharyngeal arch
1,2
2,3,4
1,3,4
Which of the following statements are correct?
The frontal process divides into medial and frontal parts.
The medial portion of the frontal process forms the olfactory pits and nasal processes.
The lateral portion of the frontal process forms the nasal septum and primary palate.
The maxillary process fuse with the medial frontonasal process and form the middle part of the maxilla- the philtrum.
The development of secondary palate is characterised by the formation of two palatal shelves on the maxillary processes and fusion with the primary palate.
The development of the maxillofacial region of the mebryo occurs in pars caudalis.
The pharangeal grooves are invaginations of the ectoderm.
The buccopharyngeal membrane ruptures, thus establishing the communication between the stomodeum and the primitive digestive tract.
The cleft palate is due to the failure of fusion of the palatine processes.
The primitive oral pit /stomodeum/ participates in the formation of the nasal and oral cavities.
Sacculus dentis gives rise to cementum, periodontal ligament and alveolar bone.
Stellate reticulum consists of tight aggregation of cells with large nucleus and long processes.
Stratum intermedium consists of one layer of star shaped cells.
Papilla dentis is ectodermal in origin.
Sacculus dentis is a concentric layer of connective tissue in which the enamel organ and dental papilla are embedded.
Fill in the gaps with the appropriate terms, to make the statements correct. The three stages of tooth development are: 1. 2. of the of the a) b) 3. and of the dental tissues.
Papilla dentis differentiates into: a) b)
A. A concentric layer of connective tissue, in which the enamel organ and dental papilla are embedded, is called dental follicle dental pulp( dental follicle, dental pulp ). B.The enamel organ functions in the formation of the crown of the tooth root( crown of the tooth, root ). C.The alveolar bone develops from the outer layer inner layer( outer layer, inner layer ) of sacculus dentis. D.The cementum enamel( cementum, enamel ) and periodontium develop from the sacculus dentis.
Vestibular proliferation of the primary epithelial band leads to the formation of .
Lamina dentis develops as a result of the proliferation of the .
Lamina dentis develops as a result of:
division of the primary epithelial band
proliferation of the lamina vestibularis
proliferation of the primary epithelial band
the basal layer of epithelium
The coat of ectodermal cells of the primitive oral pit consists of:
one layer of cells
two layers of cells
three layers of cells
multilayered epithelium
The primary tooth germs form within lamina dentis during the:
2nd-7th week of embryonic life
10th-20th week of embryonic life
7th-10th week of embryonic life
20th-30th week of embryonic life
The germs of the permanent molars arise from:
The distal extension of the dental lamina
The vestibular lamina
The primary epithelial band
The statement about the bud stage that is incorrect is:
The epithelial cells proliferate in the mesenchyme to form a tooth bud.
The cellular aggregation gives rise to the enamel organ.
The tooth bud consists of differentiated cells.
During the bell stage the dental organ:
a) Is composed of ectoderm
b) Is composed of mesenchyme
c) Develops from the lamina vestibularis
a+b+c
The tooth bud itself is a group of:
Undifferentiated epithelial cells
differentiated epithelial cells
Undifferentiated mesenchymal cells
Fibroblasts
Sacculus dentis gives rise to:
Dentin
Enamel
Cementum
Pulp
During the bell stage the inner enamel epithelium is responsible for:
Enamel formation
Dentin formation
Transport of nutrients
Determination of shape and size of the enamel.
Hertwig's epithelial rooth sheath initiates the formation of:
The crown of the tooth
The root of the tooth
The statement about the epithelial cell rests of Malassez that is correct is:
Connective tissue, located around the tooth germ.
Fibrous capsule formed around the dental organ during the bell stage.
Discrete clusters of residual cells Hertwig's root sheath.
Mesenchymal cells that are located under the enamel organ
Stellate reticulum is located:
Under stratum intermedium
Under the outer enamel epithelium
Under the inner enamel epithelium
Under the dental follicle
Papilla dentis differentiates into: 1. Enamel. 2. Dentin. 3. Cementum. 4.Dental pulp.
3,4
1,4
2,4
Stratum intermedium of enamel organ during the bell stage is located between: 1. The inner enamel epithelium. 2. The outer enamel epithelium. 3. Stellate reticulum.
2,3
1,3
Functions of the stratum intermedium are: 1. Metabolic. 2. Germinative. 3. Maintenance of the shape of the enamel organ. 4. Ensures space for the developing crown.
1,2,4
The right combination of statements about the inner enamel epithelium is: 1. Its cells are located directly above the basement membrane that separates them from the connective tissue of dental papilla. 2. It consists of cylindrical cells that have the potential to differentiate into ameloblasts. 3. It consists of star-shaped cells. 4. Its cells possess a large nucleus. 5. It consists of several layers of compactly arranged flat cells.
The right combination of statements about the dental papilla is: 1. It is located in the deeply invaginated concave side of the dental organ during the bell stage. 2. It is a formation of epithelial tissues. 3. It is mesenchymal in origin. 4. Its peripheral cells differentiate into odontoblasts.
1,2,3,4
The right combination of statements about Hertwig's epithelial rooth sheath is: 1. It is derived from the internal and external enamel epithelium of the enamel organ. 2. It participates in the root formation of the tooth. 3. It is a proliferation of epithelial cells. 4. It is mesenchymal in origin.
The initial stage of tooth development is characterised by the aggregation of undifferentiated epithelial cells in the mesenchyme and the appearance of the tooth bud.
Dental follicles are derived from the mesenchymal connective tissue surrounding the enamel organ.
Stellate reticulum is located under outer enamel epithelium and consists of 2-3 layers of cells with large nucleus and long protoplasmic processes which communicate with each other.
Lamina dentis is formed as a result of the proliferation of the primary epithelial band.
Match the layers of the enamel organ during the bell stage with their characteristics: A. Outer enamel epithelium: , B. Stellate reticulum: ,,, C. Stratum intermedium: ,, D. Inner enamel epithelium:
1. Star shaped cells 2. Short cuboidal cells 3. Compactly arranged flat cells 4. Cylindrical cells with a large nucleus 5. Cells with a low protein synthesis activity 6. It acts as a buffer zone in the enamel layer 7. It provides nutrient supply 8. It is a germinative layer
Match the layers from the first column that best relate to the items listed in the second column: A. Stomodeum: B. Guberculum dentis: C. Sacculus dentis: D. Hertwig's rooth sheath:
1. A concentric layer of connective tissue in which the enamel organ and dental papilla are embedded. 2. It is derived from the internal and external enamel epithelium of the enamel organ. 3. Primitive oral pit. 4. A band that connects the gingival lamina propria and the perifollicular tissue of the developing tooth. 5. Cells with a low protein synthesis activity 6. It acts as a buffer zone in the enamel layer 7. It provides nutrient supply 8. It is a germinative layer
In which couple of words is there no semantic context?
Proliferation- Cap stage
Mesenchyme- Papilla dentis
Stellate reticulum- Epithelial cell rests of Malassez
Inner enamel epithelium- Ameloblasts
The four layers of the enamel organ during the bell stage are: A) B) C) D)
Enamel is ectodermal in origin.
Odontoblasts are cells, present only during the tooth development, that deposit tooth enamel.
In the bell stage the "enamel pulp" consists of stellate reticulum and stratum intermedium and acts as a metabolic environment during the enamel formation.
The enamel maturation is characterised only by crystal growth.
Mature enamel consists of 70% inorganic materials, 20% organic materials and 10% water.
The basic morphological unit of enamel is the enamel rod.
The enamel rods are composed of apatite crystals.
Enamel contains a large amount of organic materials.
The rod sheaths and interrod regions of enamel contain more organic material than the enamel rods.
After their modification in the Golgi apparatus, the proteins are packaged into secretory granules, called "ameloblastic bodies".
The enamel lamellae are a type of:
Hypomineralised structure in teeth
Hypermineralised structure in teeth
Hunter and Schreger bands:
Are optical phenomenon
Represent the circadian rhythm of the enamel growth
Represent the S-shaped curve of the course of the enamel rods
Fill in the gaps with the appropriate terms, to make the statements correct. Functions of enamel organ are: 1. of matrix. 2. and of enamel matrix. 3. Determines and of . 4. Stimulates of into . 5. Formation of . 6. .
The stages of amelogenesis are: 1. . 2. .
The two types of ameloblasts during amelogenesis are: 1. . 2. .
The organic material of enamel is: a of / .
Describe the features of the enamel of newly formed teeth: 1. of . 2. . 3. in . 4. 5. .
Before the tooth eruption the exchange in enamel is from and ; after tooth eruption- the exchange direction is from .
The exchange rate in the hydroxyapatite crystal depends on the: 1. 2. of 3. and of the
The stages of the ionic exchange in the hydroxyapatite crystal of the enamel are: 1. The diffuse into the . 2. The diffuse into the of and their . 3. The ions diffuse and in the layer and are into of the . 4. The ions diffuse into the of the in an .
The ionic exchange in the enamel causes and changes.
Which are the growth lines in enamel with the following features? 1. Perpendicular to the longitudinal axis of the rods 2. Parallel to the dentino-enamel junction 3. Represent the circadian rhythm of the enamel growth
Which are the growth lines in enamel with the following features? A. Perpendicular to the long axis of the rods B. Parallel to the dentino-enamel junction C. Represent the disturbed enamel mineralisation
An exaggerated Striae of Retzius seen in histological section of all primary teeth and first permanent molars, is called .
The boundary between enamel and dentin, which is less a mineralised zone, is called .
Immediately after the eruption enamel is covered by a specific organic film that is called .
The hydroxyapatite crystal is covered by the double layer of Helmoltz which is composed of .
The statement about the enamel that is incorrect is:
It develops from the dental papilla.
It has similar hardness to diamond.
It is the hardest dental tissue.
In the enamel matrix formation participate:
Odontoblasts
Ameloblasts
The least amount of organic material in enamel is concentrated in the:
Interrod regions
Enamel rods
Intercrystal spaces
Rod sheaths
The right combination of statements about the secretory ameloblasts is: 1. The cell nucleus decreases in size 2. The cell nucleus increases in size and moves to the opposite end towards the stratum intermedium. 3. The endoplasmic reticulum is well developed. 4. The endoplasmic reticulum is not well developed. 5. There is a large number of mitochondria, RNA-granules, ribosomes in the cell. 6. The histochemical analysis detects a large amount of enzymes. 7. Golgi apparatus moves towards the dental papilla.
1,2,4,6
2,3,5,6,7
1,4,5,6
1,3,5,6
The right combination of statements about the surface aprismatic enamel is: 1. The crystals are perpendicular to the enamel surface. 2. The enamel rods are compactly arranged. 3. This layer does not contain enamel rods. 4. It contains large amounts of minerals. 5. It contains large amounts of water and calcium carbonate. 6. This layer is more resistant than the underlying ones.
2,4,5
1,3,4,6
The formation of enamel matrix does not include the:
Organising stage of the secretory ameloblasts.
Development of Tomes' process
Crystal nucleation
Formation of a walled pit in which resides the distal portion of Tomes' process
Deposition of enamel matrix inside of each pit
The statement about the initial mineralisation of the enamel matrix that are incorrect are:
The crystal nucleation is the initial deposition process of microelements in the organic matrix.
The ameloblasts are short and become more active in absorption.
The ameloblasts are short and active secretory cells.
The tall ameloblasts remove the organic material and water from the enamel ensuring the penetration of mineral salts.
The ameloblasts are short and remove the organic material and water from the enamel ensuring the penetration of mineral salts.
In the exam write down the answer with "yes" or "no".
The mineralisation of enamel closely follows the secretion of the organic matrix follows the secretion of the organic matrix.
In enamel there is a linear mode of mineralisation.
The enamel mineralisations start in the centre of the enamel rods.
The Phosphate theory is based on epitaxy- a mechanism of enamel mineralisation.
The surface aprismatic enamel is a hypomineralised area.
The tightly bound water forms the hydration layer around the apatite crystal.
The loosely bound water is located in the spaces between the crystals.
The deposition of matrix inside of each walled pit, in which resides the distal portion of Tomes' process, is a stage in formation of the enamel matrix.
The Tomes' process contains ameloblastic bodies.
Enamel undergoes entirely post-eruptive maturation.
The enamel maturation causes quality and quantity changes. 1. A reduction of the organic material and loosely bound water 2. An increase of the mineral content by a crystal growth 3. The amelogenins disappear totally during the maturation of the enamel. 4. The ionic exchange increases the resistance of the enamel. 5. The hydroxide ions in hydroxyapatite are replaced by flouride ions.
A. Quality changes: ,, B. Quantity changes: ,,
Dentin is mesenchymal in origin.
Dentinogenesis is performed by ameloblasts.
The dentin matrix as a secretory product of cells consists of fibres and amorphous substance.
The mineralisation of mature dentin matrix is linear and globular.
Dentin consists of 70% organic materials, 20% organic materials and 10% water.
The organic component of the circumpulpal dentin consists mainly of alpha fibres.
The intertubular dentin constitutes the main part of the dentin mass.
The mantle dentin is formed by ameloblasts and fibroblasts.
The predentin is an unmineralised matrix of dentin at the pulpal border of the dentin.
Dentin is covered by on the crown and by on the root, and it surrounds , located at the centre of the tooth.
The two stages of dentinogenesis are: 1. 2.
The interglobular dentin can be formed as a result of: 1. 2. 3. and during .
The of dentin matrix are synthesised during fibrillogenesis.
The morphological units of dentin are: 1. and . 2. .
The three layers of dentin are: 1. 2. 3.
The cells that secrete alpha fibres of dentin are called:
The cells that secrete the beta fibres of dentin are called:
A granular-appearing layer of dentin, underlying the cementum that covers the root is called .
The statement about dentin that is incorrect is:
It develops from the dental papilla
Bone and dentin are mineralised tissues that are similar in their structure and degree of mineralisation.
It is harder than enamel.
In the formation of the primary dentin matrix participate:
The inorganic component of dentin consists of:
Apatite crystals
Phosphoproteins
Amorphous material (MgCO3, CaCO3)
Lipids
Microelements
Water
The organic components of dentin are concentrated in the:
Intertubular dentin
Peritubular dentin
Odontoblast processes
The right combination about the secretory odontoblasts is: 1. The cell nucleus decreases in size. 2. The cell nucleus increases in size. 3. The endoplasmic reticulum is well developed. 4. The endoplasmic reticulum is not well developed. 5. There is a large number of mitochondria, RNA-granules, ribosomes in the cell. 6. The histochemical analysis detects a large amount of enzymes. 7. Golgi apparatus moves pulpally.
The statement about the dentinal tubules that is incorrect is:
They radiate outward through the dentin from pulp to enamel border.
They run parallel to the pulp cavity.
They follow an "S" shaped course with primary and secondary curvatures.
The odontoblasts line the periphery of the pulp chamber, while their processes extend into the dentinal tubules.
The basic morphological units are the:
Dentinal tubules
Rods
Fibrils
Which type of dentin is more mineralised than the other types of dentin?
Circumpulpal dentin
Secondary dentin
The statement about intertubular dentin that is incorrect is:
It is located between dentinal tubules.
It is deposited around each odontoblast process.
The organic matrix mainly consists of collagen fibres embedded in an amorphous substance.
The deposition of secondary dentin is:
Below the mantle dentin
On the walls of the pulp chamber
In the predentin layer of dentin
Granular layer of Tomes in dentin is said to be because of:
Coalescing and looping of the terminal portion of the dentinal tubules in the tooth root.
Avitaminosis C
Disturbed calcium exchange
In which couple of words is there no direct semantic context?
Around the odontoblast process - Peritubular dentin
Mantle dentin - It is more mineralised than the rest of the dentin
Ameloblasts - Mantle dentin
Circumpulpal dentin - Interglobular areas
The water content of dentin is concentrated in the: 1. Dentinal lymph 2. Odontoblast processes 3. Organic component of the inter- and peritubular dentin 4. Hydration layer of the apatite crystals
The right combination of statements about secondary dentin is: 1. Its deposition is on the walls of the pulp chamber 2. It constitutes the main part of dentin mass 3. It is poorly mineralised dentin 4. It is formed by odontoblasts
The features of dentin associated with childhood are: 1. A reduction in the dentin thickness 2. Highly mineralised dentin 3. lowly mineralised dentin 4. Ill-defined globular areas and lines 5. Large apatite crystals 6. Small apatite crystals 7. Large amounts of collagen fibres 8. Small amounts of collagen fibres 9. Wide dentinal tubules
1,2,3,5,6
1,3,4,7,8
1,2,4,5,9
1,3,6,7,9
The ionic exchange of dentin is ensured by the: 1. Enamel 2. Pulp 3. Periodontal ligament 4. Dentino-enamel junction
In the exam write down the answer as "Yes" or "No" Which of the statements are correct?
The unmyelinated nerve fibres accompany the odontoblast processes in the dentinal tubules.
The mantle dentin is less mineralised than the other layers of dentin.
The contour lines of Owen are found in the circumpulpal dentin.
The predentin is an unmineralised matrix of dentin at the pulpal border of dentin.
The organic component of the circumpulpal dentin consists of beta fibres and amorphous substance.
The predentin does not contain nerve fibres.
The contour lines of Ebner are caused by accentuated deficiencies in mineralisation.
Match the items from the first column that best relate to the items on the second column. 1. It is deposited around each odontoblast process. 2. It is a collar of more highly calcified matrix that delimits each dentinal tubule. 3. It consists of fibrils and amorphous substance. 4. It is the most highly mineralised type of dentin. 5. It is located between the dentinal tubules.
A. Peritubular dentin: ,,, B. Intertubular dentin: ,
Match the dentin types with their characteristics: 1. It is formed by fibroblasts. 2. A layer of dentin around the pulp chamber. 3. A layer of dentin below the mantle dentin. 4. It consists of collagen fibres and ground substance. 5. It consists of Beta fibres. 6. It consists of Alpha fibres.
A. Mantle dentin: ,, B. Circumpulpal dentin: ,, C. Predentin: ,,
The cross striations and striae of Retzius are: 1. The lines are perpendicular ti the longitudinal axis of the enamel rods. 2. The lines are parallel to the dentino-enamel junction. 3. The lines do not repeat at equal intervals. 4. The lines repeat at equal intervals. 5. They are less mineralised areas. 6. They represent the rhythm of the enamel matrix secretion. 7. They represent the circadian rhythm of the enamel growth. 8. They occur as a result of disturbing factors during the enamel mineralisation.
A. The cross striations: ,,,,, B. Striae of Retzius: ,,,,
