Term
| How many pharyngeal arches are there and what structures are associated with them? |
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Definition
| 5 (1, 2, 3, 4, 6). Each arch has an associated cranial nerve and arch artery. |
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Term
| What does the first arch membrane become? |
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Definition
|
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Term
| What does the first cleft become? |
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Definition
| The external auditory meatus. |
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Term
| What does the first arch become? |
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Definition
1) Meckel's cartilage in the mandible and bones of the middle ear
2) Muscles of mastication. |
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Term
| What does the second arch become? |
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Definition
1) The styloid process and upper part of the hyoid bone
2) Muscles of facial expression. |
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Term
| What does the third arch become? |
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Definition
1) Lower part of hyoid.
2) Stylopharyngeus. |
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Term
| What does the fourth arch become? |
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Definition
1) Thyroid and cricoid cartilage
2) Pharyngeal and soft palate muscles. |
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Term
| What does the sixth arch become? |
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Definition
1) Arytenoid cartilage.
2) Intrinsic laryngeal muscles. |
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Term
| What is the nerve supply to the 1st and 2nd arches? |
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Definition
|
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Term
| What is the nerve supply to the third arch? |
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Definition
|
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Term
| What is the nerve supply to the 4th arch? |
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Definition
| CN IX (glossopharyngeal). |
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Term
| What is the nerve supply to the 6th arch? |
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Definition
|
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Term
| What does each cranial nerve supplying a typical arch contain? |
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Definition
1) Brachiomotor neurons
2) General sensory neurons
3) Visceral sensory neurons. |
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Term
| What is the fate of pharyngeal arch arteries? |
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Definition
| They are remodelled to form the aorta and pulmonary trunk. |
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Term
| What does the first pouch become? |
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Definition
|
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Term
| What are the fates of teh 2nd, 3rd and 4th clefts? |
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Definition
| They become the cervicl sinus. |
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Term
| What does the 2nd pouch become? |
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Definition
|
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Term
| What does the 3rd pouch become? |
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Definition
| The parathyroid gland (inferior) and thymus. |
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Term
| What does the 4th pouch become? |
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Definition
| The parathyroid gland (superior). |
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Term
| What is the consequence of a failure clefts 2-4 to close? |
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Definition
| A brachial cyst. It remains stationary on swallowing. |
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Term
| How do the nose and lips form? |
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Definition
Upper/ lower lip: a fusion of the right and left maxillary/ mandibular processes
Nose: Endodermal nasal placode covers the frontonasal process. |
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Term
| Name the 4 kinds of cleft palate. |
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Definition
1) Unilateral cleft lip
2) Midline cleft palate
3) Bilateral cleft lip and palate
4) Bilateral cleft lip and palate continuous with cleft of secondary palate. |
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Term
| What does Treacher Collin's syndrome arise from? |
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Definition
| Hereditary defect in development of 1st arch neural crest. |
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Term
| What are Del22q11.2 syndrome and Pierre Robin sequence caused by? |
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Definition
| A neural crest cell genetic defect. |
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