development of the gastrointestinal system 2016.pdf · development of the face and teeth processes:...
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Development of the gastrointestinal system
Cranio-caudal folding of the embryo and formation of the primitive gut
Entodermal-derived structures
Processes and pharyngeal arches Aortic arches and pharyngeal pouches Developing peripherial nerves
Foregut
- stomodeum
- membrana oropharyngea
Midgut
- ductus vitellinus
Hindgut
- proctodeum
- membrana cloacae
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Development of the face and teeth
Processes:
- fronto-nasal process
- maxillar process
- mandibular process
- medial nasal process
- lateral nasal process
Epithelial thickenings:
- lens placod
- nasal placod
- otic placod
oronasal membrane,
as the primery palate Nasal placod sinks into the deep
primer nasal and oral cavities
Sulcus nasolacrimalis
ductus nasolacrimalis Junction of palatine processes and nasal septum
secondary palate
Formation of the upper lip and nasal pits
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
Arch Cartilage Bone Pouch derivates Cleft
derivates Nerve
I. Meckel’s
maxilla,
mandible,
zygomatic bone, temporal bone,
malleus, incus
▪ auditory tube
▪ middle ear cavity
▪ external
auditory meatus
N. trigeminus
(V.)
II. Reichert’s
stapes, stylod process
of os temporale, rostral part of
hyoid bone
▪ fossa tonsillaris, palatine tonsil
- N. facialis
(VII.)
III. - caudal part of
hyoid bone
▪ external parathyroid
gland,
▪ thymus
-
N. glosso-
pharyngeus
(IX.)
IV-VI.
epiglottic
arytenoid
thyroid cricoid
- ▪ internal parathyroid
gland,
▪ ultimobranchial body
- N. vagus
(X.)
Formation of the tongue:
- paired lateral lingual swellings (tuberculum laterale),
- unpaired middle swelling (tuberculum impar),
- copula (gradually atrophies)
- eminentia hypobranchialis
inner: pharyngeal pouch - outer: pharyngeal cleft
Developing organs from pharyngeal pouches and clefts
I. pharnygeal arch
I. pharnygeal arch
II. pharnygeal arch
III-IV. pharnygeal arch
Tongue muscles from occipital myotom their nerve is the n. hypoglossus (XII.)
Ductus thyreoglossus gl. thyreoidea (thyroid gland)
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Development of the gut I.
Dorsal and ventrali pancreatic buds, developing liver
Development of the ruminant composite stomach
Formation of the intraembrional coelom,
mesenterium dorsale and ventrale
Main vessels supplying the gut
Rotation around the cranio-caudal axis
(~90° turn, to the left)
Curvatura major and minor
Rotation around the dorso-ventral axis
(~45° turn: cardia gets to the left, pylorus to the right)
Mesogastrium dorsale and ventrale
Recessus pneumo-entericus
bursa omentalis + bursa infracardiaca
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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
Some congenital anomalies
umbilical hernia cleft palate, cleft lip
cloaca septum urorectale separates
rectum and sinus urogenitalis
membrana analis and
membrana urogenitalis
Meckel’s diverticulum cyst fistula
stenosis obstruction
fibrous chord