COMPARATIVE ANATOMY 6i 



end of the stomach with the superior mesenteric to help form 

 the portal. Near this union the portal also receives several 

 other veins from the stomach, duodenum, pancreas, and great 

 omentum. 



22. The Pulmonary Veins. — These were mentioned previ- 

 ously. They arise in the lungs and enter the left auricle. 



Arteries of the Cat 



1. Pulmonary Artery. — This was observed In the study 

 of the heart. Soon after leaving the right ventricle it divides 

 into two branches, one going to each lung. 



2. Aorta. — The origin of this vessel from the left ventricle 

 has already been seen. It curves dorsally and to the left, 

 forming the aortic arch. It then passes caudal on the left side 

 of the vertebral column, pierces the diaphragm, and extends 

 almost the entire length of the abdomen, running more or less 

 parallel to the Inferior vena cava. According to the region it is 

 designated thoracic or abdominal aorta. Soon after leaving the 

 heart the aorta divides into two main trunks to supply the 

 anterior parts of the body, 



3. Innominate Artery. — This Is the larger of the two main 

 branches of the aorta. A short distance from the heart the 

 Innominate gives off three large branches. The first of these 

 is the left common carotid and near It Is the right common carotid. 

 The two carotids run forward on either side of the trachea and 

 supply blood to the head and neck. The remaining part of the 

 innominate is continued as the right subclavian, which takes 

 blood to the right arm. 



4. Left Subclavian Artery. — This is the other main 

 trunk of the thoracic aorta. It carries blood to the left arm. 



It may be seen that the main arteries to the anterior part 

 of the body arise unsymmetrlcally from the aortic arch. There 

 are great variations In different species in this respect. 



From here on follow the vessels on one side only. 



5. Vertebral Artery.- — Arising from the subclavian and 

 leading directly to the vertebral column. It enters the foramen 

 transversarlum of the sixth cervical vertebra and passes to the 

 head. It supplies the muscles of the neck, and the spinal cord 

 and brain. Do not trace it beyond its entry into the backbone. 



