1 82 ELEMENTS OF MAMMALIAN ANATOMY 



17. Draw cross-section of arm at middle of humerus to show location of main 

 artery and vein. 



18. Draw cross-section of the middle region of the forearm to show location 

 of chief arteries. 



19. Draw outline of the bones of the manus and show relation of arteries to 

 the bones as seen from palmar aspect. 



20. Draw outline of femur and show course of main artery in relation to the 

 bone as seen from medial aspect. 



21. Draw outline of bones of the pes and show relations of the arteries to the 

 bones as seen from the plantar aspect. 



22. At what points in its course is the chief artery of the pelvic limb most 

 superficial? 



23. Describe the difference in structure of a vein and an artery. 



24. What veins open into each atrium of the heart? 



25. Name the veins returning the blood from each organ of the abdominal 

 cavity. 



26. Draw the portal system and label all vessels. 



27. Describe the veins returning the blood from the head. 



28. Describe the chief blood sinuses in the skull. 



29. Where are the valves found in the blood-vessels? 



30. If the brachial vein were cut, how could the blood from the manus reach 

 the heart? 



THE LYMPHATIC SYSTEM 



The lymphatics constitute that part of the vascular system 

 which collects the colorless fluid called lymph from the tissues, 

 and the chyle from the small intestine, and conveys them to 

 the external jugular veins. The portions of the lymphatic sys- 

 tem originating in the villi of the small intestine and convey- 

 ing the chyle to the left thoracic duct are known as the lacteals 

 (Fig. 71, h). 



The lymphatic system consists of four parts: (i) the lym- 

 phatic spaces between the skin and muscles in all parts of the 

 body, the spaces between the muscles adjacent to the bones, 

 and internal spaces such as those enclosed by the peritoneum 

 and pleura; (2) minute thin-walled vessels draining the spaces 

 just described and leading to larger vessels which empty into 

 the tracheal trunks or thoracic duct; (3) the glands, which 

 vary in size from a mustard-seed to two centimeters in diam- 



