Development of the gastrointestinal system
Cranio-caudal folding of the embryo and formation of the primitive gut
Foregut - stomodeum - membrana oropharyngea Midgut - ductus vitellinus
Hindgut - proctodeum - membrana cloacae Entodermal-derived structures
Processes and pharyngeal arches Aortic arches and pharyngeal pouches Developing peripherial nerves
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Development of the face and teeth
Processes: - fronto-nasal process - maxillar process - mandibular process - medial nasal process - lateral nasal process
Formation of the upper lip and nasal pits
Epithelial thickenings: - lens placod - nasal placod - otic placod
Sulcus nasolacrimalis Junction of palatine processes and nasal septum ductus nasolacrimalis
oronasal membrane, Nasal placod sinks into the deep secondary palate primer nasal and oral cavities as the primery palate
lamina labiogingivalis lip, gum
lamina dentalis dental bud
enamel organ, dental papilla, dental sac (ectomesenchymal origin)
outer and inner enamel epithelium (between them: reticulum stellatum)
odontoblasts (produce predentin dentin)
ameloblasts (produce enamel)
cementoblasts (produce cementum)
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Pharyngeal arches and their derivates
Cleft Arch Cartilage Bone Pouch derivates Nerve derivates
maxilla, mandible, ▪ auditory tube ▪ external N. trigeminus Meckel’s zygomatic bone, I. ▪ middle ear cavity auditory meatus (V.) temporal bone, malleus, incus stapes, stylod process ▪ fossa tonsillaris, N. facialis Reichert’s of os temporale, - II. palatine tonsil (VII.) rostral part of hyoid bone
▪ external parathyroid N. glosso- caudal part of - gland, - pharyngeus III. hyoid bone ▪ thymus (IX.)
epiglottic ▪ internal parathyroid arytenoid N. vagus - gland, - IV-VI. thyroid (X.) ▪ ultimobranchial body cricoid
inner: pharyngeal pouch - outer: pharyngeal cleft
Developing organs from pharyngeal pouches and clefts
Formation of the tongue: - paired lateral lingual swellings (tuberculum laterale), I. pharnygeal arch - unpaired middle swelling (tuberculum impar), I. pharnygeal arch - copula (gradually atrophies) II. pharnygeal arch - eminentia hypobranchialis III-IV. pharnygeal arch
Tongue muscles from occipital myotom their nerve is the n. hypoglossus (XII.) Ductus thyreoglossus gl. thyreoidea (thyroid gland) 3
Development of the gut I.
Main vessels supplying the gut
Curvatura major and minor Formation of the intraembrional coelom, mesenterium dorsale and ventrale Mesogastrium dorsale and ventrale Recessus pneumo -entericus bursa omentalis + bursa infracardiaca
Dorsal and ventrali pancreatic buds, developing liver
Rotation around the cranio-caudal axis Rotation around the dorso-ventral axis (~90° turn, to the left) (~45° turn: cardia gets to the left, pylorus to the right)
Development of the ruminant composite stomach
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Development of the gut II. left side view
left side view
right caudo-dorsal view
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Separation of the hindgut
cloaca septum urorectale separates membrana analis and rectum and sinus urogenitalis membrana urogenitalis
Some congenital anomalies
cleft palate, cleft lip umbilical hernia
Meckel’s diverticulum cyst fibrous chord fistula
stenosis obstruction
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