Download THE DIGESTIVE SYSTEM I

THE DIGESTIVE
SYSTEM I
The development & histology:
- primitive gut
- oral cavity, teeth, tongue
- pharynx, oesophagus
The development of the
digestive tract
the primitive gut
 stomodeum - oropharyngeal membrane
 proctodeum - cloacal membrane


dorsal mesentery
= duplicate of the splanchnopleure (peritoneum)
The Foregut Derivatives





primitive pharynx and it´s derivatives
lower respiratory system
the oesophagus and stomach
the proximal duodenum
the liver, biliary apparatus, pancreas
Ω celiac artery (truncus coeliacus)
Development of the Face
Stomodeum:
 paired mandibular prominences
 paired maxillary prominences
 single frontonasal prominence
- medial
& lateral
nasal
prominence ´
- nasal
placodes
The development
of the oral & nasal cavity

intermaxillary segment
 philtrum of the lip
 premaxillary part of the maxilla
 primary palate
 nasal septum
Development of the Palate
 primary palate
(processus palatinus medianus)
 secondary palate
- lateral palatine processes
 hard palate
 soft palate + uvula
congenital anomalies:
- critical period 6-9 weeks
- clefts (cheilo-gnatho-palato-urano-stafyloschisis)
Development of the Pharynx
proximal foregut
 pharyngeal apparatus
 arch
 pouch
 groove
 membrane

Development of the Tongue

tuberculum impar
apex a dorsum linguae
- lateral lingual swellings
 radix linguae
copula
eminentia hypobranchialis

 sulcus terminalis
Development of the Tongue
Foreamen
Caecum
Linguae
Development of the Esophagus
temporary obliteration of the lumen
 upper 2/3 - skeletal muscles
 lower 1/3 - smooth muscles
 n.X course  rotation

congenital anomalies:
- atresia (+ tracheoesophageal fistula etc.)
- congenital hiatal hernia
Structure of the Digestive Tract
 tunica
mucosa
• epithelium
• lamina propria mucosae
• lamina muscularis mucosae
 tunica
submucosa
• plexus submucosus Meissneri, glands
 tunica
muscularis externa
• circular
• plexus myentericus Auerbachi
• longitudinal
 tunica
serosa
The Oral Cavity

stratified, squamous, nonkeratin. epithelium

the lips

lamina propria mucosae
- tinny salivary or mucous gland (in the soft palate)
The Tongue



dorsal site - NO submucouse
lamina propria mucosae => high papillae
• filiform
• fungiform (some taste buds)
• foliate (in human rudimental)
• vallatae (V-shape, Ebner glands, taste buds)
skeletal muscles in three lines
Z2 - dorsum linguae (HE)
Z3 - radix linguae (HE)
Z3 - radix linguae (HE)
Z4 - tonsila lingualis (HE)
The Pharynx
 pars oralis
 pars laryngea
(stratified squamous epithelium nonkeratin.)
 pars nasalis
(pseudostratified columnar ciliated epithelium)
 tonsilla pharyngea et tubaria
The Oesophagus





stratified, squamous, epithelium
lamina propria mucosae
- cardial glands in the distal portion
mucinous glands in the submucosa
- esophageal glands
skeletal muscles in the proximal part
adventitia (serosa - abdominal portion)
Z9 - The Esophagus
Z9 - The Esophagus
The Teeth


crown, neck, root, pulp cavity
dentin
• collagen type I, GAG, hydroxyapatit
• odontoblasts

enamel
• 95% hydroxyapatit
• NO collagen x amelogenins, enamelins
• ameloblasts

dental pulp
• loose connective tissue, nociceptive neurofibres

cementum, peridontal ligaments, alveolar bone, gum
Development of the Teeth
 oral ectoderm
 mesenchyme
 neural crest cells
 odontogenesis
6th week  dental laminae
10th week - permanent teeth foundation
The Teeth Development
the bud stage
 the cap stage
- enamel organ
- dental papilla  pulp
- dental sac  cementum& periodontal ligament
 the bell stage
- odontoblasts, Tomes´ processes
- ameloblasts
- dental root

Developing tooth
- the cap stage
The end of the class
of histology & embryology…..
…so don´t forget - it´s a spring!