Development of pharyngeal arches Flashcards Preview

MD4001 Anatomy > Development of pharyngeal arches > Flashcards

Flashcards in Development of pharyngeal arches Deck (29)
1

what are the three embryonic layers of the pharyngeal arches

mesoderm core, ectoderm and endoderm

2

what does the mesenchymal core of the arches derive from

mesoderm and neural crest cells

3

what are the three developed layers of the pharyngeal arches

Mesenchymal core from mesoderm and neural crest
Internal endodermal pouch
External cleft (ectoderm)

4

what is the name for the precursor of the mouth

stomodeum

closed by the oropharyngeal membrane which later ruptures

5

what bony structures does the first arch form

maxilliary prominence
mandibular prominence

6

what are somitomeres

ill defined segments of paraxial mesoderm in the head region rostral to the somites

7

what does paraxial mesoderm form

migrates in to the pharyngeal arches to form muscle in the head and some connective tissue

8

what skeletal structures does paraxial mesoderm form

parietal, occipital, petrous temporal bone

9

what structures does the lateral plate mesoderm form

laryngeal cartilage and connective tissue

10

what skeletal structures does the neural crest form

frontal bone, sphenoid bone, squamous temporal, nasal, lamcrimal, maxilla, mandible

11

what muscles does the first arch form

muscles of mastication, ant belly digastric, mylohyoid, tensor tympani, tensor veli palatini

12

what skeletal elements does the first arch form

maxilla, zygomatic bone, mandible, malleus, incus

13

what muscles are formed from the second arch

muscles of facial expression, stylohyoid, stapedius, posterior belly of digastric

14

what skeletal elements are formed from the second/ hyoid arch

stapes, styloid process, lesser horn of the hyoid and upper body of hyoid

15

what muscle is made from the third arch

stylopharyngeus

16

what skeletal structurs are made from the third arch

greater horn of the hyoid, lower part of body of hyoid

17

what nerve is associated with the third arch

glossopharyngeal

18

what muscles are derived from the 4th and 6th arches

all the muscles of the pharynx except stylopharyngeus

all the muscles of the palate except tensor veli palatini

cricothyroid

all the muscles of the larynx `

19

what skeletal structures are made from the 4th and 6th arches

epiglottis, laryngeal cartilages, thyroid, cuneiform , coniculate, arytenoids

20

what artery does the 4th right arch give

subclavian artery

21

what artery does the 6th arch give

pulmonary arteries

22

Paraxial mesoderm

All voluntary muscles, arteries,
neurocranium, meninges, dorsal skin

23

Lateral plate mesoderm

Laryngeal car1lages; regional connec1ve 1ssue

24

what does Neural crest form

Pharyngeal arch skeleton,
Also viscerocranium,
glandular connective tissue,
parts of the neurocranium, teeth, interact with
ectodermal placodes for ganglia/sensory nerve forma1on

25

what do Ectodermal placodes form

with neural crest to form neurones of sensory ganglia
(V,VII, IX and X) also sensory apparatus (eyes/nose not shown)

26

what is an ectopic thymus

thymus remains in the neck

27

what is treacher collins sydrome

autosomal dominant
first/ second arch

defective treacle protein
failure of apoptosis of neural crest cells and migration

abnormal eye shape
micrognathia
hearing loss
underdeveloped zygoma
malformed ears

28

what are the features of digeorge syndrome

3rd and 4th pouches fail to develop and thymus and parathyroids are defective

CATCH-22
cardiac abnormality
abnormal facies
thymic aplasia
cleft palate
hypocalcaemia

deletion in chromosome 22- de novo

29

what is the role of sonic hedghog protein in craniofacial patterning

governs the width of facial features

inadequate function- narrowing and fusion, cyclopia

excessive SHH widening and structures duplicated