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Tne Digestive System 



A. Introduction 



1. General structure and regions of the early digestive tube or primitive metenteron 



a. Definition 



b. Two main types of the early metenteron 



2. Basic structure of the early metenteron (gut tube) 



a. Basic regions of the primitive metenteron 



1 ) Stomodaeum 



2) Head gut or Seessel's pocket 



3 ) Foregut 



4) Midgut 



5) Hindgut 



6) Tail gut (post-anal gut) 



7) Proctodaeum 



b. Basic cellular units of the primitive metenteron 



3. Areas of the primitive metenteron from which evaginations (diverticula) normally 

 arise 



a. Stomodaeum 



b. Pharynx 



c. Anterior intestinal or pyloric area 



d. Junction of midgut and hindgut 



e. Cloacal and proctodaeal area 



B. Development of the digestive tube bv metenteron 



1. General morphogenesis of the digestive tube 



2. Histogenesis and morphogenesis of special areas 

 a. Oral cavity 



1 ) General characteristics of the stomodaeal invagination 



2) Rudiments of the jaws 



3) Development of the tongue 



4) Teeth 



a) General characteristics 



b) Development of teeth in the shark embryo 



c) Development of teeth in the frog tadpole 



d) Development of the egg tooth in the chick 



e) Development of teeth in mammals 



5) Formation of the secondary palate 



6) Formation of the lips 



7) Oral glands 



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