Study On The Casting Of Intrarenal Arteries And The Kidney Collecting System Of Yak

This study was conducted to explore the branching and distribution of the yak intrarenal arteries and to explore the renal collecting system of the yak.The ABS(acrylonitrile butadiene styrene)casting technique was employed to perfuse the renal artery and collecting system in 44 yak kidneys.According to the shape of yak kidney and intrarenal arteries distribution,the yak kidney was divided into three parts: cranial pole,mesorenal and caudal pole,and the mesorenal consist of mediolateralis and mediomedialis.The results of arteries showed that the yak had only one renal artery,and primary branches were formed near the renal hilum to the cranial and caudal trunk.Branched vessels from the cranial trunk are distributed in the cranial pole and mediolateralis of the kidney,and vessels from the caudal trunk were distributed in the caudal pole and mediomedialis.Because of the different shapes of the left and right kidneys,the secondary branches(segmental arteries)of the renal artery were also different.In the right kidney,the cranial trunk gave rise to the apical,upper,and mediolateral segmental arteries,and the caudal trunk gave rise to the mediomedial,and lower segmental arteries.In the left kidney,the cranial and caudal trunks usually bifurcated into dorsal and ventral segmental arteries.No anastomose was seen between the segmental arteries.The results of yak kidney collecting system showed that the renal pelvis was present in all casts and is classified into 2 types,dilated or nondilated(58.3%),with or without the dilated origin of the ureter.All casts had 2 major renal calyces toward the cranial and the caudal poles.Minor renal calyces were connected to the major renal calyces by an infundibulum,which drained 1 to 5 minor renal calyces.The number of minor renal calyces in caudal region was significantly more than that in cranial(P<0.01).The yak kidney collecting system was classified into 2 types according to the character of drainage.The type A,which was composed of collection system that presented two major caliceal groups and mid-zone drainage was dependent on these major groups,and type B,which mid-zone drainage was independent of the polar caliceal groups,the type A(70.8%)was more common than type B(29.2%)in yak.