480 



URINARY ORGANS OF THE OX 



thin-walled tubes, the calyces majores; the anterior calyx is usually the larger. 

 Each calyx major gives off a niunber of branches, and these divide into several 

 funnel-shaped calyces minores, each of which embraces a renal papilla. The 

 space not occupied by the calyces and vessels is filled with fat. 



On section through the kidney the renal pyramids are easily made out. The 

 blunt apex of each pyramid, the papilla renalis, projects into a calyx minor. On 

 each papilla are small orifices (Foramina papillaria) by which the terminal renal 

 tubules (Ductus papillares) open into the calyx. The renal columns are much 

 more distinct than in the horse. 



At the hilus the renal artery is dorsal, the vein in the middle, and the ureter 

 ventral; a quantity of fat surrounds these structures in the hilus. 



The kidneys of the sheep are bean-shaped and smooth, without any superficial 

 lol:)ation. The soft organ is regularly elliptical in form, with convex dorsal and 

 ventral surfaces and rounded extremities; its length is al)out 2^2 to 3 inches (ca. 

 5 to 8 cm.), its width about 13^2 to 2 inches (ca. 4 to 5 cm.}, and its thickness a little 



Fig. 3S-1. — Kidney of Sheep, Ventral View. 

 T'.T'., Branches of renal vein. 



Fig. 3S5. — Kidney of Sheep, Horizontal Section. 

 1, Cortical substance; 2, medullary substance; 

 S, renal crest; 4. renal pelvi.«; 5, ureter. (From Leiser- 

 ing's Atlas, reduced.) 



more than 1 inch (ca. 3 cm.). In position they resemble those of the ox, except that 

 the right one is usually a little further back, and lies under the first three lumbar 

 transverse processes. The average weight of each is about four ounces. The 

 hilus is in the middle of the inner border. There is a renal crest or common papilla 

 formed by the fusion of twelve to sixteen pyramids. 



When the rumen is full, the left kidney (which is attached by a short mesentery) usually 

 lies entirely to the right of the median plane, under the third, foiu-th, and fifth lumbar tran.s- 

 verse processes. The primitive dorsal surface has become ventro-medial, and is somewhat 

 flattened by contact with the rumen. 



The ureters are, in general, like those of the horse, except in regard to the 

 first part of the left one, which has a peculiar course, in conformity with the remark- 

 able position of the kidney. It begins at the ventral part of the hilus (which faces 

 toward the right), curves upward and inward over the outer aspect of the kidney 

 to its dorsal surface, crosses the median plane, and runs backward on the left side. 



The bladder is longer and narrower than that of the horse, and extends further 

 forward on the abdominal floor. The peritoneal coat extends backward further 

 than in the horse. 



