DISSECTION OF THE DOG 67 



submucous tissue. Around the vessel the fibres are disposed in loops : and 

 between the two areas and along the greater curvature, longitudinal fibres 

 connect the two sphincters. 



The deepest fibres, oblique in direction, are best examined from within. 

 To do this the stomach must be turned inside out, and the mucous membrane 

 examined and removed. The mucous lining is in the form of a soft membrane, 

 in the main similar to that of the intestine. It may be divided into three 

 areas. A small cardiac portion at the oesophageal opening is somewhat pale 

 and moderately smooth. The fundus portion fines the rest of the body of the 

 stomach and is markedly rugose and dark red in colour. The pyloric area 

 is smoother and paler. The three areas distinguishable by the naked eye 

 correspond to the distribution of microscopic glands of different character. 



Now remove the mucous membrane and observe the loose and highly 

 vascular submucous tissue, beneath which is the third stratum of muscle. 

 The deep, oblique muscular fibres are most plentiful about the cardiac orifice, 

 where they form an elongated horseshoe-like loop. 



Interior of the duodenum. — The duodenum should be opened by an 

 incision along its greater curvature. The wall of the tube has a structure 

 similar to that of the rest of the small intestine. The mucous membrane has 

 a markedly velvety appearance due to the presence of innumerable delicate 

 filiform villi, and is longitudinally folded. Pass a probe along the bile-duct 

 and observe how obliquely it passes through the. wall of the duodenum to 

 open on a broad blunt papilla surmounting one of the longitudinal folds. 

 While within the substance of the duodenal wall, the duct is included between 

 the longitudinal and circular layers of the muscular coat. 



The opening of the ductus pancreaticus accessorius will also be found 

 on the summit of a blunt papilla. 



Dissection. — If the subject be a female those reproductive organs which 

 are contained within the abdomen must now be examined. 



The female reproductive organs consist of the two ovaries, each with a 

 uterine tube by which the ovum travels to the uterus, the uterus, the vagina, 

 the urogenital sinus, and the vulva and external genitals. Of these, the 

 vagina, urogenital sinus, and vulva, fall to be considered with the pelvis ; but 

 the other organs above named are contained in the abdomen. 



Uterus. — The uterus can generally be seen, in part at least, as soon as 

 the abdomen is opened and before the intestinal mass is disturbed. It con- 

 sists of a single portion, the body (corpus uteri), in the form of a short tube 

 placed between the bladder and the rectum, and two cornua. The pelvic 

 end of the body, connected with the vagina, is known as the neck of the uterus 

 (cervix uteri) ; whereas the cranial end forms the fundus of the uterus (fundus 



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