798 DIRECTIONS FOB LABORATORY WORK 



an additional innermost oblique layer may appear). Is a mesothelial 

 layer present in the tunica adventitia? Sketch l.p. (240) a narrow seg- 

 ment through the complete wall. 



(2) Compare the above section with sections through the middle and 

 upper third of the esophagus. What differences obtain at these levels 

 in the several tunics? 



(3) Compare a section through the upper third of the esophagus 

 with one through the pharynx. (A longitudinal section through the 

 area of transition from pharynx to esophagus is preferable.) What 

 takes the place in the pharynx of the muscularis mucosse of the esoph- 

 agus? Note that in the upper end of the esophagus a third innermost 

 stratum of oblique or longitudinal striped muscle fibers may occur in 

 the tunica muscularis. 



(4) Study sections through the upper cardiac glands (superficial 

 esophageal glands). Sketch (241). 



(5) Sketch small portions of the my enteric (242), and the sub- 

 mucous nerve plexuses (243). 



(G) THE STOMACH (V entriculus ; Gaster}. 



(1) Study l.p. a stained longitudinal section through the area of 

 transition from the esophagus to the cardiac portion (pars cardiaca) of 

 the stomach. Note the tunica serosa of the cardia. Make sketch (244) 

 including the four tunics. Sketch h.p. (245) a cardiac gland. 



(2) Study a section through the pars fundica of the stomach (fun- 

 dus ventriculi). Sketch l.p. (246). Examine carefully under h.p. a 

 gastric gland of this region and note: a, mouth; b, foveola (crypt, pit) ; 

 c, neck (cervix) ; d, body (corpus) ; and e, fundus. Note the different 

 types of epithelium occurring in the several regions. Sketch h.p. (247) 

 a complete gland, noting especially the chief and parietal cells. Sketch 

 h.p. (248) a transverse section through the body of a gastric gland. 

 Look for a lenticular gland' (solitary lymph nodule) in the tunica 

 mucosa. 



(3) From a demonstration slide prepared by the Golgi technic 

 sketch h.p. (249) a portion of a longitudinal section of the secretory 

 region of the fundic gland to show the main lumen and the system of 

 inter- and intracellular secretory canaliculi. 



(4) S.tudy a section of the pars pylorica of the stomach. Sketch 

 l.p. (250). Sketch h.p. (251) a gastric gland of this region. In what 

 features do the pyloric and fundic glands differ? How do they differ 

 functionally as indicated by these features? Enumerate four salient 



