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39 Cards in this Set
- Front
- Back
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1. When do pharyngeal arches appear?
What do they play an important role in? |
4-5 wks
1. Formation of the face 2. Formation of the neck structures |
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2. What does the pharyngeal arch consist of?
How are they separated? |
Core of mesenchyme covered externally by ectoderm and internally by foregut endoderm
By deep clefts (pharyngeal clefts or grooves) |
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3. What does the stomodeum form from?
What does it surround? |
Foregut
Surrounds the oral plate |
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4. How does blood get to the pharyngeal arches?
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Each arch has own blood supply
**arotic arches |
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5. How is each arch separated?
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1. Pharyngeal cleft (groove) on outside
2. Pharyngeal pouch on inside |
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6. What makes up the pharyngeal membrane?
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Ectoderm of pharyngeal cleft w/ endoderm of pharyngeal pouch
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7. What does each arch consist of?
Four things... |
1. Cartilage
2. Aortic arch 3. Cranial nerve 4. Mesenchyme |
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8. At 5 weeks what is present?
What surrounds this? Where is ectoderm found? |
Stomadeum
-Surrounded by the 1st arch -Ectoderm suurounds stomadeum Ectoderm is found anterior to the tonsilar fossa |
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9. From what 3 sources is the mesenchymal core derived from?
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1. Paraxial mesoderm
2. Lateral plate mesoderm 3. Neural crest cells -cells come from ectoderm at junction of neural plate |
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10. What does the paraxial mesoderm form?
Four things |
1. Floor of brain case
2. Soem of occipital region 3. Dermis and CT in dorsal heat 4. Meniges |
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11. Where do neural crest cells migrate to?
What do they form? |
Pharyngeal arches
(from forebrain, midbrain, and hindbrain) 1. Cartilage 2. Bone 3. Dentin 4. Sensory neurons and glandular stroma |
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12. What three things make up the skull?
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1. Cranial vault
2. Cranial base 3. Face |
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13. What is meckel's cartilage associated with?
What does it not do? Which nerves is associated w/ Meckel's cartilage? |
1st pharyngeal arch
Does NOT develop into mandible (bone) Trigeminal nerve (5th cranial nerve) |
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14. Ectodermal placodes and neural crest cells form the neurons of which sensory ganglia?
Where does these neurons migrate to? |
5th (trigeminal)
7th (facial) 9th (glassopharyngeal) 10th (vega) Neurons migrate into each arch **Each arch is innervated by its own cranial nerve that migrates w/ the developing muscles |
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15. The 1st arch develops into what 4 prominences?
What does the 1st pharnygeal cleft give rise to? What do the 1st and 2nd arches give rise to? |
Two maxillary prominences
Two mandibular prominences External auditory meatus External ear |
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16. What is the region between the 2nd arch and 3rd, 4th, and 6th arches called?
What does the endoderm of the 1st pharyngeal pouch give rise to? (two things) |
Cervical sinus
1. Middle ear cavity 2. Auditory tube |
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17. What is the fate of the ectoderm of the 1st arch?
5 things... |
1. Skin over maxilla, mandibule, some around ear and external auditory meatus
2. Salivary glands 3. Enamel of teeth 4. Epithelium of buccal cavity 5. Epithelium over anterior body of tongue |
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18. What does the endoderm and mesoderm of the 2nd pharyngeal pouch give rise to?
What is special about the palatine tonsillar fossa? |
Palatine tonsillar fossa
**secondarily lymphatic tissue is incorporated into the pouch Demarks junction between pharynx and oral cavity |
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19. What does the 3rd pharyngeal pouch give rise to?
What does the 4th pouch give rise to and why is this important? |
Thymus and parathyroids
**cortical comes from ectoderm **medullary comes for endoderm Parafollicular cells **important for Ca++ homeostasis |
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20. What muscles does the mesoderm of the 1st pharyngeal arch give rise to?
Which nerve innervates the first arch? |
Muscles of mastification
**5th nerve innervates 1st arch |
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21. What cartilage does the mesoderm of the 1st arch give rise to?
three things... |
1. Maxillary and mandibular bones
2. Incus 3. Malles (from Meckel's cartilage) |
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22. Much of the head cartilage develops from what?
What does the mesenchyme of the mandibular process differentiate into? |
Mesenchyme of neural crest origin
Meckel's cartilage |
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23. Which nerves innervate the pharyngeal arches?
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1st arch: 5th cranial nerve
2nd arch: 7th cranial nerve 3rd arch: 9th cranial nerve 4th arch: 10th cranial nerve |
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24. From what do the neural crest cells in the head region arise from?
What gene is important in development of arches 2-4? Why? |
Rhombomeres
Hox genes Rhombomeres depend on expression of different Hox genes **Different gene expression leads to neural crest cells in different arches |
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25. What else is important in regulation?
What can regulate HOX gene expression? |
Epithelial mesenchymal interactions
Sonic Hedgehog and retinoic acid |
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26. What three swellings formed mainly by the 1st pharyngeal arch develop into the face?
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1. Maxillary prominence
2. Mandibular prominence 3. Frontonasal prominence |
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27. Where is the maxillary prominence located?
What does it develop from? What does it become? |
On either side of the stomodeum
Develops from the 1st brachial arch Becomes cheeks and lateral portion of upper lip |
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28. What does the mandibular prominence form?
What does it develop from? What does it become? |
Forms the inferior boundary of the stomodeum
Develops from fusion of right and left mandibular processes of the 1st branchial arch Becomes lower lip |
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29. What does the frontonasal prominence form?
What does it become? |
Forms the upper border of the stomodeum
Becomes forehead and nose |
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30. What processes make up the nasal pit?
By week 5 how is the face? What induces the nasal placodes |
Lateral and medial nasal process
Has 5 facial prominences and 2 nasal placodes Ectoderm induced by ventral forebrain |
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31. During week 5 what happens?
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Nasal placodes invaginate and form nasal pits
Two new prominences appear -lateral nasal prominence -medial nasal prominence |
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32. Over the next 2 wks what happens to the maxillary processes and the medial nasal prominences?
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Maxillary processes
-increase in size -grow to midline Medial nasal prominence -grow to midline |
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33. When the medial nasal prominences fuse in the midline what do they give rise to?
What does the maxillary process fuse with? |
Philtrum and 4 upper incisors
Medial nasal processes **Rest of teeth in upper jaw come from maxillary process |
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34. If the maxillary process does not fuse w/ the medial nasal prominence what can occur?
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1. Cleft lip
2. Cleft jaw 3. Cleft palate |
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35. What does the upper lip develop from?
What separates the maxillary prominence and the lateral nasal prominence? What does the lower lip develop from? |
2 medial nasal prominences
2 maxillary prominences Nasolacrimal groove Merger of mandibular prominences |
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36. From what do the cheeks develop from?
What is the nose formed from? |
Maxillary prominence
1. Frontal prominence (bridge) 2. Medial nasal prominence (crest/tip) 3. Lateral nasal prominence (alae) |
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37. How is the intermaxillary segment formed?
What are it's 3 components? What does it fuse w/? |
Fusion of 2 medial nasal prominences
1. Labial component -philtrum of upper lip 2. Upper jaw component -4 incisor teeth 3. Palatal component -primary palate Nasal septum from frontal prominence |
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38. What does the primary palate develop from?
How is the secondary palate formed? What is the junction between the secondary and primary palate? |
Develops from intermaxillary segments
Forms from 2 outgrowths of the maxillary prcoesses (palatine shelf) Incisive junction |
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39. What separates the nasal cavity from the oral cavity?
What happens as the oronasal breaks down? What happens with the formation of the secondary palate? |
Oronasal membrane
Primitive choanae Definitive choanae |
