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The development of the head and neck

The development of the head and neck. Carnegie 13 (28 – 32 days) 4 – 6 mm, 30 somites. Vývoj hlavy, krku. pharyngeal arches. lips oral cavity vestibule teeth tongue hard palate soft palate pharynx larynx. parotid gland submandibular gland sublingual gland. thyroid gland

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The development of the head and neck

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  1. The development of the head and neck

  2. Carnegie 13 (28 – 32 days) 4 – 6 mm, 30 somites Vývoj hlavy, krku pharyngeal arches

  3. lips • oral cavity • vestibule • teeth • tongue • hard palate • soft palate • pharynx • larynx

  4. parotid gland • submandibular gland • sublingual gland

  5. thyroid gland • parathyroid gland • 4 bodies • thymus http://www.mayoclinic.com/images/image_popup/pthyroid.jpg

  6. Development of the digestive tube • primitive gut • formed during the 4th week, as the head, tail and lateral folds incorporate a part of the yolk sack into the embryo • foregut (preentereon) – separated from the stomodeum (primitive mouth) by membrana oropharyngea, protrusion of the base of the lower respiratory tract • midgut (mesenteron) – distally from the liver bud to ductus vitellinus • hindgut (metenteron) – further, separated from proctodeum (anal pit) by membrana cloacalis

  7. Origin of the mesenchyme • paraaxial mesoderm (non-segmented) • bonesofthe base oftheskullandsomeofthebonesofcalvaria • alltheskeletalmuscles • dermis andfibroustissue on thedorsal part ofthehead • ectomesenchyme (fromtheneuralcrest) • skeleton ofthefaceandpharyngealarches • ectodermalplacodes (thickenedareasofectoderm) • pharyngealarches • occipitalsegments (basis etcondyliossisoccipitalis)

  8. Pharyngeal apparatus • pharyngeal arches (arcus pharyngei) • pharyngeal pouches(sacci pharyngei) • pharyngeal grooves(sulci pharyngei) • pharyngeal membranes(membranae pharyngeae) Thomas W. Sadler, Langman´ Medical embryology, 10th edition

  9. Pharyngeal arches (arcus pharyngei) • paired structures • begin to develop in the 4th-5th week • separation of the columns of the mesenchyme: • there are pharyngeal grooves on the outer side (depressions in the ectoderm) • there are pharyngeal pouches on the inner side (formed by the endoderm of the primitive larynx) • grooves and pouches never merge (no gills form) • the mesenchyme of neural crest cells is streaked by paraaxial mesoderm and in each pharyngeal arch gives rise to muscles • cartilages and skeleton of the arches are differentiated from the ectomesenchyme • each arch is innervated by a cranial nerve and has its own artery (aa. arcuum pharyngeorum = aortic arches) • 5th arch does not arise

  10. Aortic arches(Aa. arcuum pharyngeorum)

  11. Derivatives of the pharyngeal arch arteries I • 1st pair – arteria maxillaris + carotis externa • 2nd pair – arteria stapedia • 3rd pair – proximally - arteria carotis communis - distally - arteria carotis interna

  12. Derivativesofthepharyngeal arch arteries II • 4th pair – • left – part of arcus aortae • right – a. subclavia dx. • distal part of a. subclavia dx.comes from aorta dorsalis dextra • a. subclavia sin.is not a derivative of arcus aortae, but of the 7th intersegmental artery

  13. Derivativesofthepharyngeal arch arteries III • 5th pair - Ø • 6th pair – • left prox. arteria pulmonalis sinistra dist. ductus arteriosus (Botali) • right prox. arteria pulmonalis dextra dist. Ø

  14. First pharyngeal arch (arcus pharyngeus primus) • 2 processes • maxillary (cranially) • mandibular (caudally) • contains the Meckel´s cartilage (gives rise to malleus and incus) • formation of the lower jaw • merging of the right and left mandibular process, subsequent membranous ossification Thomas W. Sadler, Langman´ Medical embryology, 10th edition

  15. Second pharyngeal arch (arcus pharyngeus secundus) • cartilage (= Reichert´s cartilage) • by merging of the right and left arch in the midline a part of the body and lesser horns of a hyoid bone are formed Thomas W. Sadler, Langman´ Medical embryology, 10th edition

  16. Third pharyngeal arch • cornua majora + caudal part of corpus ossis hyoideum • innervation: n. IX Fourth pharyngeal arch • merges with the 6th arch • cartilago cricoidea + thyroidea • muscles of larynx, palate (apart from m. tensor veli palatini), pharynx (apart from m. stylopharyngeus) • innervation: n. X (n. laryngeus sup.)

  17. Fifth pharyngeal arch • does not arise in human Sixth pharyngeal arch • merges with the 4th arch • muscles of larynx • innervation: n.X (n. laryngeus recurrens – contains the fibres from n.XI)

  18. Pharyngeal pouches (sacci pharyngei) • human embryo has 5 pouches • their endoderm gives rise to branchiogenic organs Thomas W. Sadler, Langman´ Medical embryology, 10th edition

  19. First pharyngeal pouch • recessus tubotympanicus (tubotympanic recess) • blind recess (toward the 1st pharyngeal groove) • its end is broaden into the primitive tympanic cavity • medial part remains straight • tuba auditiva Eustachii • together with the 1st pharyngeal groove participates in formation of an eardrum (membrana tympanica)

  20. Second pharyngeal pouch • base of the palatine tonsil (tonsilla palatina) • fossa supratonsillaris http://biology.clc.uc.edu/fankhauser/labs/microbiology/strep_detection/strep_test.htm

  21. Third pharyngeal pouch • dorsal part • inferior parathyroid bud • ventral part • thymic bud • bases migrate caudally

  22. Fourth pharyngeal pouch • dorsal part • superior parathyroid bud • ventral part • rudimentary • ultimopharyngeal body (corpus ultimopharyngeum / ultimobranchiales) • cells from the neural crest • differentiate into the parafolicular C-cells of the thyroid gland (calcitonin)

  23. Pharyngeal grooves • 4 paires of grooves are formed within the 5th week • dorsal part of the 1st groove persists as the external acoustic meatus (meatus acusticus externus) • epithelium on the floor creates the outer surface of an eardrum (membrana tympanica) • other grooves come to lie in a depression sinus cervicalis (cervical sinus) • sinus cervicalis is obliterated as the neck develops, lateral cervical cysts may persist fistulae

  24. Lateral cervical fistula http://journals.tums.ac.ir/full_text.aspx?org_id=59&culture_var=en&journal_id=4&issue_id=1293&manuscript_id=11415&segment=en http://www.ultratwistersgym.com/Resources/Head/Head%20and%20Neck.html

  25. Tongue - innervation • n. V3 • n. lingualis • n. VII • chorda tympani • n. IX. • n. X.

  26. Development of the tongue I • 4th week: on the inner side of the pharyngeal pouches (primordia lingualia) • 1st arch: tuberculum impar (wears off) + 2 tubercula lingualia lateralia apex + dorsum linguae (n.V3) • 2nd arch: copula (wears off) - n.VII- chorda tympani (taste) • 3rd-4th arch: eminentia hypobranchialis radix linguae (n.IX, n.X) • sulcus terminalis (separates the body and the root of the tongue) • 4th arch epiglottis (n. X) • muscles: • from myotomes of the occipital somites (n. XII) • from the 4th arch (n. X - m. palatoglossus)

  27. Development of the tongue II Thomas W. Sadler, Langman´ Medical embryology, 10th edition

  28. Congenital abnormalities of the tongue • cysts and fistulae – remnants of the thyroglossal duct • ankyloglossia (tongue-tie) • short frenulum linguae • macroglossia • microglossia • glossoschissis (= cleft tongue) • rare, incomplete cleft

  29. Ankyloglossia http://www.ghorayeb.com/TongueTie.html

  30. Macroglossia x Microglossia http://www.consultantlive.com/display/article/10162/43839 http://dentallecnotes.blogspot.cz/2011/08/developmental-disturbances-of-tongue.html

  31. Development of the thyroid gland • the growth of the epithelium between tuberculum impar and copula (later location of foramen caecum) • growths in front of the pharynx in a caudal direction • within the descent is connected to the tongue thanks to ductus thyroglossus • progressive descent in front of the hyoid bone and the cartilages of the larynx • within the 7th week gets to its final place in front of the trachea • gets functional at the end of the 3rd month

  32. Congenital abnormalities ofthe thyroid gland • thyroglossal duct cysts • may form anywhere along the course of it during the descent of the thyroid gland from the tongue • thyroglossal duct fistulae • communication of the cysts with the outer space • ectopic thyroid gland • along the course of the descent • most often at the root of the tongue • this tissue may be functional

  33. Thyroglossal duct cysts http://www.surgical-tutor.org.uk/default-home.htm?tutorials/thyroglossal.htm~right http://www.learningradiology.com/archives06/COW%20231-Thyroglossal%20Duct%20Cyst/tgdccorrect.html

  34. Processus pyramidalis glandulae thyroideae • the most common congenital abnormality • along the course of the descent • 40 % http://www.anatomyatlases.org/AnatomicVariants/OrganSystem/Images/82.shtml

  35. DiGeorge‘s syndromeAplasia thymoparathyroidea microdeletion 22q11.2 1:3000

  36. Development of the face I • facial primordia appear at the end of the 4th week (neural crest ectomesenchyme of the 1st pharyngeal arch) around the stomodeum • maxillary prominences laterally • mandibular prominences caudally • frontonasal prominence cranially • on each side develop bilateral oval thickenings of the surface ectoderm nasal placodes • they depress within the 5th week nasal pits • pits are bordered by horseshoe-shaped elevations = medial and lateral nasal prominences

  37. Development of the face II Thomas W. Sadler, Langman´ Medical embryology, 10th edition

  38. Development of the face III • maxillary prominences enlarge (cheeks and upper jaw) and growth medially – pressing medial nasal prominences to the midline, then they merge • upper lip is formed by the maxillary prominences and medial nasal prominences • lower lip and jaw are formed by mandibular prominences that merge in the midline • nose arises from 5 sources: • frontonasal prominence, 2 medial nasal prominences, 2 lateral nasal prominences

  39. Development of the oral and nasal cavity stomodeum • a pit lined with ectoderm boundaries: • lower processes of the 1st pharyngeal arch – mandibula • on sides upper processes of the 1st pharyngeal arch – maxilla • frontonasal prominence with nasal placodes from above ( pits, vesicles, open into the primitive oral cavity), medial and lateral nasal prominences • membrana oropharyngea (buccopharyngea) breaks up on the 26th day

  40. Development of the palate I • primary palate • from intermaxillary segment (by merging of both medial nasal prominences) • lip component philtrum • component for the upper jaw (carries 4 incisors) • palatine component (forms the primary palate) • passes continuously into the nasal septum (from the frontonasal prominence) • secondary palate • by merging of the palatine processes of the maxillary process (6th week) • fusion with the primary palate (os incisivum) in front

  41. Development of the palate II Thomas W. Sadler, Langman´ Medical embryology, 10th edition

  42. Separation of the oral and nasal cavity Thomas W. Sadler, Langman´ Medical embryology, 10th edition

  43. Cleft malformations of the face and the palate I • lack of fusion of the structures (1:550) • anterior palate clefts (cheiloschisis, cheilognathoschisis) • lateral cleft lip, clet upper jaw, cleft between the primary and secondary palates • partial or complete lack of fusion of the maxillary prominence with the medial nasal prominence on one or both sides • posterior palate clefts (palatoschisis) • cleft secondary palate, cleft uvula • combination of clefts lying anterior as well as posterior to the incisive foramen (cheilo-gnatho-palatoschisis) • oblique facial clefts • failure merging of the maxillary prominence with its corresponding lateral nasal prominence • median (midline) cleft lip • rare abnormality • incomplete merging of the two medial nasal prominences in the midline

  44. Cleft malformations of the face and the palate II http://blog.johnrchildress.com/2011/06/07/real-leadership-and-hope/ Thomas W. Sadler, Langman´ Medical embryology, 10th edition http://www.craniofacial.net/cleft-lip-cleft-palate-only

  45. Cleft malformations of the face and the palate III before before after after http://www.rodina.cz/clanek3188.htm

  46. Development of the salivary glands • epithelial pouches of the oral cavity (6th – 8th week) • the intergrowth into the adjacent ectomesenchyme  its connective tissue comes from the neural crest • parenchyme ( secretion) comes from the proliferating oral epithelium • ectoderm  gl. parotis • endoderm  gl. submandibularis et sublingualis

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