embryology of head and neck

Question 1

when does the face form

Answer 1

weeks 4-14

Question 2

when does the thyroid, thymus and parathyroid form

Answer 2

weeks 4-7

Question 3

what are the bones around the brain called

Answer 3

the neurocranium (8 bones)

Question 4

what are the facial bones called

Answer 4

the viscerocranium (15 bones)

Question 5

what are the flat bones of the neurocranium and what is this group called

Answer 5

frontal and parietal bones
calvaria

Question 6

what are the bones of neurocranium that make up the base of the skull

Answer 6

the chondrocranium

Question 7

what is the cellular origin of the facial bones and frontal bone

Answer 7

neural crest cells from the dorsal part of neural tube

Question 8

what is the cellular origin of the skull bones (minus the frontal)

Answer 8

the paraxial mesoderm, cells that are cranial to the somites
called: unsegmented, somitic, somitomeric or pre-otic

Question 9

what is the cellular origin of the laryngeal bones

Answer 9

the lateral plate mesoderm

Question 10

what is endochondral ossification

Answer 10

formation of a cartilage template and then formation of bone

Question 11

what is intramembranous ossification

Answer 11

direct formation of bone

Question 12

what skull bones form via endochondral ossification

Answer 12

occipital bone (chondrocranium)

Question 13

what skull bones form via intramembranous ossification

Answer 13

the parietal and frontal bones

Question 14

what are sutures important for

Answer 14

molding at birth

Question 15

where do sutures arise from

Answer 15

sagital: neural crest
coronal: paraxial mesoderm

Question 16

When do the anterior and mastoid fontanelles close?

Answer 16

around 2 years

Question 17

when do the posterior and sphenoidal fontanelles close

Answer 17

after 6 months

Question 18

what is craniosynostosis

Answer 18

premature fusion of sutures

Question 19

scaphocephaly is what

Answer 19

a long AP skull due to early fusion of sagittal suture

Question 20

bradycephaly is what

Answer 20

a short square shaped skull due to early coronal fusion

Question 21

Crouzon syndrome

Answer 21

AD
FGFR2 gain of function mutation
craniosynostosis, ocular proptosis, mandibular prognathism, progressive hydrocephaly

Question 22

Apert syndrome

Answer 22

AD
FGFR2 gain of function mutation
craniosynostosis, syndactyly of hands and feet, mental retardation

Question 23

Pfeiffer syndrome

Answer 23

AD
FGFR2 gain of function mutation
craniosynostosis, syndactly of hands and feet

Question 24

when do pharyngeal arches form

Answer 24

in the 4th week

Question 25

what are pharyngeal pouches

Answer 25

evaginations of the endoderm between arches

Question 26

what are pharyngeal clefts

Answer 26

invaginations of ectoderm between arches

Question 27

how many arches, pouches and clefts

Answer 27

5 arches, 4 pouches and clefts

Question 28

what does each arch contain

Answer 28

cartilage, muscles, artery and nerve

Question 29

where does the muscle of pharyngeal arches come from

Answer 29

somitic mesoderm

Question 30

where does the artery of pharyngeal arches come from

Answer 30

somitic mesoderm

Question 31

where does the cartilage of pharyngeal arches come from

Answer 31

lateral plate neural crest cells

Question 32

where does the nerve of pharyngeal arches come from

Answer 32

neural tube (ectoderm)

Question 33

how does the mandible form

Answer 33

intramembranous ossification

Question 34

what is and does meckels cartilage form

Answer 34

It is the first pharyngeal arch the mandible, incus and malleus

Question 35

what is and does Reicherts cartilage form

Answer 35

It is the 2nd pharyngeal arch the lesser horn of hyoid, styloid process, stapes

Question 36

what does the 3rd pharyngeal arch form

Answer 36

the greater horn of hyoid bone

Question 37

what is the origin of the 1, 2 and 3rd pharyngeal arches

Answer 37

the neural crest cells

Question 38

what is the origin of the IV and VI pharyngeal arches

Answer 38

lateral plate mesoderm

Question 39

what do the 4th and 6th pharyngeal arches form

Answer 39

thyroid cartilage, cricoid cartilage and arytenoid cartilage

Question 40

what nerve innervates the 1st arch

Answer 40

trigeminal nerve (CN V)

Question 41

what nerve innervates the 2nd arch

Answer 41

facial nerve (CN VII)

Question 42

What nerve innervates the 3rd arch

Answer 42

glossopharyngeal nerve (CN IX)

Question 43

what nerve innervates the 4th and 6th arch

Answer 43

the superior laryngeal branch and the recurrent branch of the vagus (CN X)

Question 44

what does cleft 1 form

Answer 44

the external auditory meatus and the external part of the tympanic membrane

Question 45

what forms the cervical sinus

Answer 45

cleft 2 migrates and 3 and 4 curl up

Question 46

what does pouch 1 form

Answer 46

the tubotympanic recess that becomes the Eustachian tubes

Question 47

what does pouch 4 form

Answer 47

the ultimobranchial body and superior paraythyroid

Question 48

what does pouch 2 form

Answer 48

the tonsil

Question 49

what does pouch 3 form

Answer 49

the inferior parathyroid and the thymus

Question 50

when is the thymus active

Answer 50

during perinatal period and childhood and then involutes after puberty

Question 51

what does PTH do

Answer 51

increases Ca2+ levels in the blood

Question 52

where is the thyroid gland derived from

Answer 52

not from a pouch from the floor of pharynx between pouch 1 and 2 (endoderm)

Question 53

what are the hypoglossal ducts

Answer 53

they connect the foramen cecum to the thyroid gland

Question 54

when does thyroid function begin

Answer 54

week 10-12

Question 55

what does the ultimobranchial body do

Answer 55

fuses with thyroid gland and creates calcitonin producing 'C' cells

Question 56

what is the derivative of C cells

Answer 56

endoderm

Question 57

what does calcitonin do

Answer 57

reduces calcium levels in the blood

Question 58

first arch syndromes

Answer 58

insufficient migration of neural crest cells into pharyngeal arch 1 - treacher-collin syndrome - Pierre robin syndrome

Question 59

treacher collins syndrome

Answer 59

AD TCOF1 gene mutation, treacle protein mutation causes: hypoplasia of mandible, external ear abnormalities

Question 60

Pierre robin syndrome

Answer 60

SOX9 gene associated u shaped cleft palate, glossoptosis and airway obstruction

Question 61

DiGeorge syndrome cause

Answer 61

failure of pouches 3 and 4 to differentiate into thymus and parathyroid glands - micro deletion of chromosome q22 - abnormal neural crest migration

Question 62

DiGeorge syndrome symptoms

Answer 62

facial anomalies immunosuppression (thymus) hypocalcemia (parathyroid)

Question 63

Pharyngeal fistula

Answer 63

persistence of pouch 2 or cleft 2 anterior border of SCM

Question 64

pharyngeal cyst

Answer 64

persistence of clefts 2, 3, 4 along angle of mandible drainage in palatine tonsil

Question 65

thyroglossal cysts and sinuses

Answer 65

if the thyroglossal duct persists and forms a cyst - located in midline near hyoid

Question 66

thyroglossal cyst under the tongue

Answer 66

lingual cyst

Question 67

derivative of frontal nasal prominance

Answer 67

forehead, dorsal and apex of nose

Question 68

derivative of lateral nasal prominance

Answer 68

alae (sides) of nose

Question 69

derivative of medial nasal prominance

Answer 69

nasal septum, ethmoid bone, cribriform plate

Question 70

derivative of intermaxillary segment

Answer 70

philtrum and primary plate

Question 71

derivative of maxillary prominance

Answer 71

upper cheek region and lip

Question 72

derivative of mandibular prominance

Answer 72

chin, lower lip and cheek

Question 73

derivative of fusion of Fr. nasal and max pr

Answer 73

nasolacrimal duct

Question 74

what is the name of the opening form the nasal cavity to the mouth

Answer 74

choana

Question 75

how does that hard palate form

Answer 75

intramembranous ossification

Question 76

what is in the soft palate

Answer 76

muscles vagus and trigeminal nerves

Question 77

what is choanal atresia

Answer 77

cyclical period of cyanosis due to a closed choana

Question 78

the anterior 2/3 of the tongue is formed by what

Answer 78

the first arch

Question 79

the posterior 1/3 of the tongue is formed by the what

Answer 79

the third arch

Question 80

what forms the epiglottis

Answer 80

the 4th arch

Question 81

what is ankyloglossia

Answer 81

tongue tied

Question 82

innervation of anterior 2/3 of tongue

Answer 82

trigeminal ganglion

Question 83

innervation of taste buds

Answer 83

facial nerve

Question 84

innervation of posterior tongue and epiglottis

Answer 84

vagus nerve

Question 85

innervation of posterior 1/3 of tongue and vallate apillae

Answer 85

glossopharyngeal nerves

Question 86

tongue musculature innervation

Answer 86

hypoglossal nerve cranial nerve XII

Question 87

what is the dental papilla

Answer 87

a transient signalling structure that signals to form the enamel knot

Question 88

precursor of enamel

Answer 88

ameloblasts

Question 89

precursor of predentin

Answer 89

odontoblasts

Question 90

morphogen means

Answer 90

dose dependent signalling

Question 91

defect resulting in loss of Shh defects

Answer 91

severe midline defects

Question 92

low Shh activity

Answer 92

cyclopia

Question 93

very high Shh activity

Answer 93

facial duplications

Question 94

holoprosencephaly

Answer 94

cyclopia

Question 95

what is the cause of cleft lip

Answer 95

failure of maxillary prominance and medial nasal prominance joining

Question 96

cleft palate cause

Answer 96

failure of palatal shelves (primary and secondary) fusing together along midline

Question 97

cleft lip is where in relation to incisive foramen

Answer 97

anterior

Question 98

cleft palate is where in relation to incisive foramen

Answer 98

posterior

Question 99

clefts distribution among sexes

Answer 99

lip more common in men palate more common in females