Past Years Exam
Challenge 2010
propound
Past Years Exam
Lecture Title : Past Year Exam
Prof name
: Dr.Ashraf AlShawesh
Provided by
: Khalid Mortaja
Oral Histology questions (1st part: embryology)

(1) Endoderm is a development of embryonic:
1. Epiblast
2. Hypoblast
3. Cytotrophoblast
4. Exocolemic membrane

(2) Which is false about Pre-Embryonic stage:
1. amniotic cavity lies between cytotrophoblast and epiblast
2. exocolemic cavity is a development of blastocoel
3. exocolemic membrane lines primitive yolk sac
4. mesoderm is formed before endoderm

(3) prochordal plate is caused by:
1. thickening of ectoderm
2. thickening of endoderm
3. thickening of mesoderm
4. none of the above

//(4) mesoderm separates ectoderm from endoderm in all embryo
except:
1. prochordal plate
2. notochord
3. exocolemic membrane
4. cloacal membrane

(5) mesoderm gives all these tissues except:
1. dental tissues
2. bone
3. muscle
4. respiratory system()
5. lymph cells

(6) lining of the lung are formed by:
1. ectoderm
2. mesoderm
3. endoderm
4. none of the above

(7) ectoderm develops to give all listed tissues except:
1. skin
2. oral epithelium
3. enamel
4. dentin
5. nervous system

(8) which is true about notochord:
1. its formation starts at prochordal plate
2. its formation ends at primitive pit
3. it will form back bones
4. it lies between ectoderm and mesoderm
5. all of the above

(9) intermediate mesoderm will form all these organs except:
1. adrenal medulla
2. adrenal cortex
3. urinary system
4. reproductive system

(10) correct order of the following embryo structures before folding
is:
1. septum transversum – oropharyngeal membrane –
developing heart – brain
2. septum transversum - developing heart - oropharyngeal
membrane – brain
3. brain - oropharyngeal membrane - septum transversum developing heart
4. brain - developing heart - oropharyngeal membrane septum transversum

(11) the fastest growing part of embryo is:
1. kidney
2. brain
3. neurons
4. mouth

(12) bilaminar embryonic disk is formed in:
1.pre embryonic stage
2.embryonic stage
3.fetal stage
4.before fertilization

(13) which part of the blastocyst is responsible for the attachment of
the embryo to the wall of the uterus:
1. inner cell mass
2. embryo proper
3. trophoblast
4. blastocoel

(14) what is false about early embryo formation:
1. zygote grow by mitotic division
2. a 12-16 cells zygote is called morula
3. embryo proper is responsible for making up embryo tissues
4. zygote grow in size during its development into blastocyst

(15) embryonic phase:
1. it lasts from fertilization until 8 weeks
2. development of tissues and organs happens in it
3. zygote implanted in the wall of the uterus during it
4. it is safe to take a PA radiograph for a pregnant woman
during this period

(16) all sentences regarding maxilla are true, except:
1. maxilla proper ossify firstly
2. pre maxilla ossify lately
3. it is made by endochondral ossification
4. it contribute to palate formation

(17) what is the foramen that found between the anterior 2/3 and
posterior 1/3 of the tongue:
1. foramen ovale
2. foramen rotundum
3. foramen magnum
4. foramen cecum

(18) all these sentences regarding mandible formation are true,
except:
1. ossification starts at 7 weeks
2. meckel's cartilage contribute to its body formation by
endochondral ossification
3. parts of the mandible are formed in response to muscle
action
4. condylar growth ends at the age of 21

(19) all these parts contribute to palate formation, except:
1. zygomatic process
2. maxillary process
3. lateral palatine process
4. medial palatine process

(20) ossification of maxilla starts at:
1. 3 weeks in utero
2. 32 days in utero
3. 40 days in utero
4. 60 days in utero

(21) Cranial nerve VII will give what type of innervations to the
tongue:
1. general sensation to anterior 2/3
2. taste sensation to anterior 2/3
3. general sensation to posterior 1/3
4. taste sensation to posterior 1/3
5. motor innervations

(22) thyroglossal duct extends between:
1. tip of the tongue and thyroid gland
2. sulcus terminalis and thymus gland
3. epiglottis and parathyroid gland
4. foramen cecum and thyroid gland

(23) mid portion of the nose is formed by:
1. frontonasal process
2. maxillary process
3. mandibular process
4. 1st branchial arch
5. 2nd branchial arch

(24) Muscles of mastication are originated from:
1. 1st branchial arch
2. 2nd branchial arch
3. 3rd branchial arch
4. 4th branchial arch
5. 6th branchial arch

(25) Blood supply of the head and neck region of the embryo at the
age of 4 months came from:
1. common carotid artery
2. external carotid artery
3. internal carotid artery
4. aortic arch vessels
5. none of the above
before weak 7  internal carotid artery
after weak 7  external carotid artery

(26) all middle ear bones are formed from 1st branchial arch, except:
1. stapes
2. malleus
3. incus
4. all of the middle ear bones formed from 1st arch

(27) greater horn of hyoid bone is formed by:
1. 1st branchial arch
2. 2nd branchial arch
3. 3rd branchial arch
4. 4th branchial arch
5. 6th branchial arch

(28) Mandible is formed around which part of meckel's cartilage:
1. anterior
2. middle
3. posterior
4. ventral
5. dorsal

(29) pharyngeal pouches are lined by:
1. ectoderm
2. mesoderm
3. endoderm
4. oral epithelial cells

(30) first stage of recognizable face occurs at:
1. 3rd week
2. 4th week
3. 5th week
4. 6th week
5. 7th week

(31) In chondrodysplasia, patient suffer from insufficient growth of:
1. base of the skull
2. flat bones of the skull
3. long bones
4. 1+3
5. 2+3
6. 1+2

(32) Heart starts to beat in embryo at:
1. 3 weeks
2. 4 weeks
3. 5 weeks
4. 6 weeks

(33) All these structures are formed by neural crest cells except:
1. pulp
2. enamel
3. cementum
4. dentin
5. melanocyte

(34) melanocyte can be found in which part of the skin:
1. stratum corneum
2. stratum lucidium
3. stratum spinosium
4. stratum basale
5. all of the above

(35) all these structures are formed from interaction between
ectoderm and mesoderm, except:
1. sweat glands
2. hair
3. nail
4. tooth
5. salivary glands

(36) cartilage is formed by which part of the mesoderm:
1. paraxial
2. middle
3. lateral plate
4. all of the above

(37) growth of cartilage by making new cell layers on the outer
surface of already formed one is called:
1. interstitial
2. intramembranous
3. endochondral
4. appositional

(38) Angiogenic clusters found in the wall of primary yolk sac will
form:
1. central nervous system
2. gastrointestinal system
3. respiratory system
4. cardiovascular system

(39) first skeletal component of embryo is:
1. long bones
2. flat bones
3. hyaline cartilage
4. elastic cartilage
5. fibrous cartilage

(40) type of the ossification in the body of the mandible:
1. intramembranous ossification
2. endochondral ossification
3. central ossification
4. peripheral ossification
Prepared and revised by:
Dr. Hamza Khalaf Kharashgeh
Mobile number: 0795710627
E-Mail: hamzkk@yahoo.com
Answers:
1. 2
2. 4
3. 2
4. 3
5. 1
6. 3
7. 4
8. 3
9. 1
10. 2
11. 2
12. 1
13. 3
14. 4
15. 2
16. 3
17. 4
18. 2
19. 1
20. 3
21. 2
22. 4
23. 1
24. 1
25. 2
26. 1
27. 3
28. 1
29. 3
30. 1
31. 4
32. 2
33. 2
34. 4
35. 1
36. 1
37. 4
38. 4
39. 3
40. 1
Oral Histology questions (2nd part)

(1) All sentences regarding amelogenisis are true, except:
1. amelogenisis starts mainly in bell stage
2. different stages of amelogenisis can be found on different
areas of internal enamel epithelium
3. external enamel epithelium deposits and modify enamel (
internal )
4. amelogenisis is a process that has an end point

(2) during pre-secretory stage of amelogenisis:
1. differentiation of internal enamel epithelium takes place
firstly at cervical region and proceeds occlusally
2. IEE change their shape from columnar to cuboidal
3. resorption of dental lamina occurs in this stage
4. differentiation of ameloblasts precedes odontoblasts
differentiation

(3) proximal terminal web consists of:
1. gap junctions between ameloblasts and stellate reticulum
2. gap junction between adjacent ameloblasts
3. desmosomes between ameloblasts and stellate reticulum
4. desmosomes between adjacent ameloblasts

(4) tome's process of ameloblasts develops during:
1. pre-secretory stage
2. secretory stage
3. transition stage
4. maturation stage
5. post maturation stage

(5) which is false about formation of enamel prisms:
1. enamel formation starts firstly at prism periphery
2. tome's process is responsible about prism formation
3. ameloblasts develops tome's process at proximal end
4. more than one ameloblasts contribute to form one prism

(6) regarding enamel mineralization, which is false:
1. organic matrix get mineralized by hydroxyapatite crystals
2. all crystals are parallel to Tome's process surfaces
3. each tome's process has 2 mineralization fronts
4. first crystals are thin and smaller than mature one

(7) all these actions happens during transition stage of amelogenisis,
except:
1. ameloblasts become larger in size and length
2. ameloblasts change from secretory form into maturation
form
3. initially deposited enamel is converted into fully mineralized
4. blood vessels invaginate enamel organ

(8) regarding enamel proteins, what is true:
1. 90% of enamel proteins are non - amelogenins
2. 10% of enamel proteins are amelogenins
3. enamelin and tuftelin are considered non – amelogenins
4. tuftelin is lighter than amelogenins

(9) maturation of enamel involves:
1. removal of non – amelogenins from enamel matrix
2. addition of phosphorus and fluoride ions
3. removal of water and organic matrix
4. enamel crystals decrease in size with increase in intercrystal
spaces

(10) all listed below is true about maturation stage, except:
1. tome's process of ameloblasts are lost during it
2. organelle content of ameloblasts is increased
3. addition of calcium to enamel matrix
4. distal part of ameloblasts become ruffle ended

(11) regarding reduced enamel epithelium, which is false:
1. it is formed by all enamel organ layers in addition to primary
enamel cuticle
2. it is formed during post maturation stage
3. primary enamel cuticle is formed from amorphous protein
layer under flattened ameloblasts
4. it protect enamel surface after eruption

(12) regarding early bell stage:
1. there is an active cell division under future cusp tips
2. there is cessation of cell division at future fissure sites
3. dental lamina breaks down and loose connection with oral
epithelium
4. there is a differential cell division along EEE to map out
Occlusal surface

(13) stratum intermedium cells appear in:
1. bud stage
2. early cap stage
3. late cap stage
4. early bell stage
5. late bell stage

(14) cells of enamel organ that maintain its shape:
1. IEE
2. EEE
3. stellate reticulum
4. stratum intermedium
5. 1+2
6. 2+4
7. 2+3

(15) which is false about remnants of broken dental lamina:
1. associated with the etiology of cysts
2. form epithelial rests of malassez
3. they are broken in early bell stage
4. form epithelial rests of serrez

(16) all sentences regarding early tooth development are true, except:
1. dentin formation precedes enamel formation
2. IEE induce dental papilla to differentiate and form dentin
3. dentin induce differentiation of IEE into ameloblasts
4. in permanent tooth development, part of EEE grow lingually
to form successor lamina

(17) apposition of minerals and hard tissue formation starts during:
1. bud stage
2. early cap stage
3. late cap stage
4. early bell stage
5. late bell stage

(18) a transient structure that may be involved of mechanical
transformation of cap stage into bell stage:
1. enamel knot
2. enamel cord
3. enamel navel
4. enamel niche

(19) regarding enamel knot, which is false:
1. they are a localized mass of cells in the center of IEE
2. they are non proliferative cells
3. they produce signaling molecule
4. it contribute cells to form enamel cord
5. they bulge into enamel organ

(20) nerve supply to enamel organ starts as plexus under dental
papilla in:
1. bud stage
2. cap stage
3. early bell stage
4. late bell stage

(21) blood vessels invade dental papilla during :
1. bud stage
2. early cap stage
3. late cap stage
4. early bell stage
5. late bell stage

(22) regarding early tooth development:
1. primary epithelial band is formed in response to interaction
between ectoderm and endoderm
2. vestibular lamina is the lingual part of primary epithelial
band
3. dental lamina is arch shaped and produce enamel organs
4. dental lamina is the buccal part of primary epithelial band

(23) which is false about shape determination of enamel organ:
1. EEE maintain the shape of enamel organ
2. stellate reticulum has hydrostatic pressure that allow
proliferation of EEE and shaping of the crown
3. shape determined by cell proliferation and movement
4. differential cell division along IEE shape the Occlusal pattern
of the crown

(24) each of the below is correct regarding bud stage of enamel organ,
except:
1. cells of enamel organ are fully histo-differentiated
2. basal lamina of enamel organ still intact
3. shape of enamel organ is spherical
4. poor morpho-differentiation

(25) we can define 2 parts (central and peripheral) in enamel organ
during:
1. bud stage
2. early cap stage
3. late cap stage
4. early bell stage
5. late bell stage

(26) cells of IEE during early cap stage are:
1. columnar
2. flattened
3. star shaped
4. cuboidal

(27) stellate reticulum part of the enamel organ appears during:
1. bud stage
2. early cap stage
3. late cap stage
4. early bell stage
5. late bell stage

(28) which is false about late cap stage:
1. central portion of enamel organ become separated with
intracellular spaces
2. IEE became columnar
3. stratum intermedium cells appear during this stage
4. mesenchymal cells around enamel organ will form dental
papilla and follicle

(29) all sentences are true regarding mineralization of enamel, except:
1. calcium reaches enamel matrix principally from enamel
organ
2. crystal growth and nucleation induced by tuftelin
3. amelogenins are capable of self assembling of crystal nucleus
into nanospheres
4. HA crystals grow in width more than in length

(30) enamel:
1. thicker at cervical margin and thinner over cusp tips
2. has high tensile strength
3. grayish in color
4. does not undergo replacement or repair
5. has low shear strength

(31) largest crystal size can be found in:
1. bone
2. enamel
3. dentin
4. cementum
5. cartilage

(32) hydroxyapatite crystals of enamel:
1. make 88-90% of enamel by weight
2. mineral content of HA crystals is higher in enamel near DEJ
3. core of crystal is less soluble than periphery
4. crystals are pentagonal and of great length

(33) fluoride ions replace which ion of HA crystals:
1. OH
2. HCO3
3. Mg
4. Ca

(34) all of the below is correct regarding enamel prisms, except:
1. boundaries of prisms reflects sudden change in crystal
orientation
2. prisms meet enamel surface at 90 degrees on cervical region
3. prisms meet enamel surface at 90 degrees on occlusal surface
4. enamel prisms extends from DEJ to enamel surface

(35) most predominant pattern of enamel prisms:
1. pattern I
2. pattern II
3. pattern III
4. pattern IV

(36) which is false regarding keyhole pattern of enamel prisms:
1. tail of one prism lies between heads of other 2 adjacent
prisms
2. between 2 keyholes, change in orientation of HA crystals is
abrupt
3. in head, HA crystals are parallel to long access
4. in tail, HA crystals are perpendicular to the long access

(37) regarding aprismatic enamel:
1. crystals in this layer are parallel to the surface
2. it is less mineralized than prismatic enamel
3. it occurs due to the presence of tome's processes
4. it make the outer 20 – 100 micrometer of enamel in
permanent teeth

(38) which is false regarding cross striation:
1. cross striations are at right angle with long access of prisms
2. it reflects weekly interval
3. cross striations are 2.5 – 6 micrometer apart
4. it is formed due to short periods of activity alternating with
periods of quiescence

(39) structural fault through entire enamel thickness is called:
1. enamel spindle
2. enamel tuft
3. enamel lamella
4. none of the above

(40) aged enamel:
1. lighter in color
2. less fluoride content
3. porosity increased
4. harder and less susceptible to caries
Prepared and revised by:
Dr. Hamza Khalaf Kharashgeh
Mobile number: 0795710627
E-Mail: hamzkk@yahoo.com
Answers:
1. 3
2. 3
3. 3
4. 2
5. 3
6. 2
7. 1
8. 3
9. 3
10. 2
11. 4
12. 3
13. 4
14. 7
15. 2
16. 4
17. 5
18. 2
19. 5
20. 2
21. 4
22. 3
23. 2
24. 1
25. 2
26. 4
27. 3
28. 3
29. 4
30. 4
31. 2
32. 2
33. 1
34. 3
35. 3
36. 4
37. 4
38. 2
39. 3
40. 4
Prepared and revised by:
Dr. Hamza Khalaf Kharashgeh
Mobile number: 0795710627
E-Mail: hamzkk@yahoo.com
Prepared and revised by:
Dr. Hamza Khalaf Kharashgeh
Mobile number: 0795710627
E-Mail: hamzkk@yahoo.com