THE VASCULAR SYSTEM l8l 



(Fig. 90), the right subcardino-supracardinal anastomosis 

 (subc. -supra, anas.) , the right subcardino-postcardinal anastomo- 

 sis (subc.-pc.-an.) the intersub-cardinal anastomosis (I. S. A.), 

 the pars subcardinalis (P. Sub) and the pars hepatica (P. Hep.)-" 

 Figure 90 is also introduced to aid the student interpret some 

 of the variations in the venous system likely to be found in 

 the cat. Huntington and McClure list some seventeen types 

 of variation which may be explained. (Anatomical Record, 

 Vol. 20, page 14.) There may be double postcava, persistence of 

 right postcardinal, or subcardinal, or in some animals and 

 in man of the renal collar. Students are advised to look for 

 and make records of such variations as they may find in their 

 dissection. They will find great pleasure in trying to interpret 

 them embryologically. 



LABORATORY STUDIES AND SUGGESTIONS 



1. What holds the heart in place? 



2. Draw the ventral aspect of the heart with the pericardium removed and 

 label all features. 



3. When the heart is detached from the body, how do you distinguish the 

 dorsal from the ventral aspect? 



4. How many veins open into each atrium? 



5. What arteries lead from each ventricle? 



6. After dissecting write a detailed description of the valves of the heart. 



7. Describe the difference in the appearance of the walls of the aorta and 

 vena cava. 



8. From your dissection write a description of the features seen in each cavity 

 of the heart. 



9. Name the branches of the thoracic aorta in order. 



10. Name the branches of the abdominal aorta and tell what organs each 

 supplies. 



11. Draw the celiac axis and its branches throughout their course and label 

 all parts. 



12. Show by a drawing the relations of the aorta and venae cavae throughout. 



13. Make a diagrammatic cross-section of the neck, showing location of 

 arteries and veins. 



14. Describe the three routes by which blood may reach the brain and the 

 two routes by which it may be returned to the heart. 



15. Name the arteries arising from the arch of the aorta, 



16. Draw the inner or medial aspect of your dissection of the arteries of the 

 thoracic limb and label all parts. 



