BLOOD VESSELS 807 



(6) the right carotid, running along the 

 trachea, dividing into the right 

 internal carotid to the brain, and 

 the right external carotid to the 

 head and face ; 

 (c) the left carotid, with a similar course 

 thereafter the aorta gives off — 



the left subclavian artery, which branches like the right ; 



the cceliac artery to the liver, stomach, and spleen ; 



the anterior mesenteric to the pancreas and intestine ; 



the renal arteries to the kidneys ; 



the single posterior mesenteric to the rectum ; 



the paired spermatic or ovarian arteries to the reproductive 



organs ; 

 the lumbar arteries to the posterior body wall. 

 The aorta is continued terminally in the median sacral artery to the 

 tail, and laterally in the common iliacs, which form the femorals of 

 the hind-legs, and give off in the abdomen several branches to the 

 abdominal walls, the pelvic cavity, the bladder, and the uterus. 



The two superior venae cavae bring blood from the head, neck, 

 thorax, and fore-limbs. Each is formed from the union of — 

 a subclavian from the shoulder and fore-limb, 

 an external jugular from the face and ear, 

 an internal jugular from the brain, 



an anterior intercostal from the spaces between the anterior ribs, 

 an internal mammary from the ventral wall of the thorax ; 

 and the right superior vena cava also receives an azygos cardinal vein, 

 which runs along the mid-dorsal line and collects blood from the 

 posterior intercostal spaces. 



The inferior vena cava is a large median vein lying beside the aorta 

 beneath the backbone. Anteriorly it is embedded in the liver, and 

 receives the hepatic veins. Thence it passes through the diaphragm 

 into the right auricle. Posteriorly the inferior vena cava has the 

 following components : — 



internal ihacs from the back of the thighs, forming by their union 



the beginning of the inferior vena cava ; 

 femoral veins from the inner borders of the thighs, continued into 



external iliacs which open into the inferior vena cava ; 

 paired ilio-lumbars from the posterior abdominal walls ; 

 spermatic or ovarian veins from the reproductive organs ; 

 renal veins from the kidneys. 

 There is no renal-portal system. 



The food which has been digested— rendered soluble and diffusible — 

 passes from the food canal into the vascular system by two paths — 

 (a) All except the fatty material is absorbed by veins from the 

 stomach and intestine. These unite in a main trunk, the 

 portal vein. The components of the portal vein are — the lieno- 

 gastric from the stomach (and also from the spleen), the 

 duodenal from the duodenum (and also from the pancreas), 

 the anterior mesenteric from the intestine, the posterior 

 mesenteric from the rectum. The portal vein breaks up 



