Embryology

Question 0

Name of arch 1

Answer 0

Meckel’s

Question 1

Neural crest cells can produce

Answer 1

Cranial and sensory ganglia
Adrenal medulla (chromaffin cells)
Melanocytes
Branchial arch cartilage
Parasympathetic plexus in gut
C cells of thymus
Bulbar and Conan ridges of heart
Schwann cells
Arachnoid and pia mater

Question 2

Name of arch 2

Answer 2

Reichert’s

Question 3

Cartilage in arch 1 forms

Answer 3

Malleus and incus

Question 4

Cartilage in arch 2 forms

Answer 4

Stapes and stylus

lesser horn and body of hyoid

Question 5

Cartilage of arch 3 forms

Answer 5

Greater horn and body of hyoid

Question 6

Cartilage of arches 4 and 6 form

Answer 6

Larynx

Question 7

Nerve supply to Branchial arches 1,2,3,4&6

Answer 7

V3, VII, IX, X

Question 8

Muscles formed by arch 1

Answer 8

Mastication
Mylohyoid
Half digastric
Tensor tympani
Tensor palatini

Question 9

Muscles formed by arch 2

Answer 9

Facial expression
Stapedius
Stylohyoid
Half digastric

Question 10

Muscles formed by arch 3

Answer 10

Stylopharngeus

Question 11

Muscles formed by arches 4&6

Answer 11

Pharynx
Larynx
Levator of palate
Oesophagus

Question 12

Structure formed by pouch 1

Answer 12

Auditory tube

Question 13

Structure formed by pouch 2

Answer 13

Palatine tonsil

Question 14

Structure formed by pouch 3

Answer 14

Parathyroid gland

Thymus

Question 15

Structure formed by pouch 4

Answer 15

Parathyroid gland

Ultimo-brachial body (C cell of thyroid)

Question 16

Structure formed by first dorsal cleft

Answer 16

External auditory meatus

Question 17

Describe basic development of thyroid

Answer 17

Down growth from tongue (ant 2/3 and post 1/3 junction) thyroid diverticulum
Foramen cecum formed on tongue
Thyroglossal duct from foramen cecum to thyroid

Question 18

Anterior 2/3 of tongue formed by arch?

Answer 18

1

Question 19

Nerve supply to anterior 2/3 of tongue

Answer 19

Motor -XII
General sensory - V3
Special sense - VII

Question 20

Nerve supply to posterior 2/3 of tongue

Answer 20

Motor - XII
General sensation - IX
Special sense - IX

Question 21

Remnant of notochord in adult

Answer 21

Nucleus pulposis of intervertebral disk

Question 22

Part of somites that forms vertebral column

Answer 22

Sclerotome

Question 23

Division of alar and basal lamina/plates

Answer 23

Sulcus limitans

Question 24

Cell type that forms neural tube

Answer 24

Neuroepithelial cells

Question 25

Zones of neural tube

Answer 25

1. Ventricular - ependymal cells 2. Intermediate/ mantle - grey matter 3. Marginal - white matter

Question 26

Three primary brain vesicles

Answer 26

Prosencephalon Mesencephalon Rhombencephalon

Question 27

Rhombencephalon forms

Answer 27

1. Metencephalon (pons and cerebellum) | 2. Myelencephalon (medulla)

Question 28

Divisions of occipital somites

Answer 28

Pre otic Pre orbital Pre occipital

Question 29

What is formed from Pre occipital so mites

Answer 29

Muscles of tongue

Question 30

What is formed by Pre otic and Pre orbital somites

Answer 30

Extrinsic muscles of eye

Question 31

What forms filtrum

Answer 31

Downgrowth of frontonasal prominence

Question 32

What structures join to form nasolacrimal duct

Answer 32

Frontonasal prominence | Maxillary prominence of Branchial arch 1

Question 33

What embyological defect causes DiGeorge syndrome

Answer 33

Abnormal development of the third and fourth branchial arches. Thymic hypo/a-plasia

Question 34

Describe process of neurulation

Answer 34

Week 3 - midline ectoderm thickens forming neural plate. Neural plate wider at cephalic end. Lateral plate edges thicken = neural folds (induced by underlying notochord and somites) Folds develop and neural groove is seen Folds meet and fuse to form neural tube

Question 35

Anomalies of neural crest cell migration

Answer 35

Treacher Collin's syndrome | Albinism

Question 36

Describe embryological development of vertebral column

Answer 36

Neural tube lies posterior to notochord Mesenchymal blocks on either side of notochord Medial somites = sclerotome Week 4 - Sclerotome migrates and clusters around notochord Week 6 - differentiate into chondroblasts separated by mesenchyme Week 8 - expansion of chondroblasts eliminates notochord

Question 37

Main steps of palatogenesis

Answer 37

- elevation - horizontal growth - midline contact, adhesion - fusion

Question 38

Morphological stages of early tooth development

Answer 38

- bud - cap - bell - terminal differentiation

Question 39

Describe odontoblasts

Answer 39

- neural-crest derived mesenchymal cells - form predentin - calcifies to form dentin

Question 40

What do ameloblasts do?

Answer 40

- produce enamel

Question 41

Adontia

Answer 41

Total lack of tooth development

Question 42

Dentinogenesis imperfecta

Answer 42

Teeth are translucent and roughened with severe amber discoloration

Question 43

Dentine dysplasia

Answer 43

Primary teeth are translucent and amber but secondary central incisors are normal

Question 44

Amelogenesis imperfecta

Answer 44

Abnormal tooth enamel formation

Question 45

Hypodontia

Answer 45

Lack of development of one or more teeth

Question 46

Hypohidrotic ectodermal dysplasia

Answer 46

Maldevelopment of one or more ectodermal-derived tissues

Question 47

How many permanent teeth should we have?

Answer 47

32

Question 48

Embryonic origin of cranial and spinal meninges

Answer 48

- somatic and cephalic mesoderm | - neural crest cells

Question 49

Factors that influence the effect of a teratogen on embryonic development

Answer 49

- robusticity (genetics) of the baby - sex of baby (boys more ecosensitive) - timing of exposure - amount of exposure - duration of exposure

Question 50

What originates from neural crest cells

Answer 50

- cranial and sensory ganglia and nerves - adrenal medulla - melanocytes - branchial arch cartilages - bulbar and clonal ridges of the heart - meninges - cranial mesenchyme and connective tissue