116 



ANATOMY AND PHYSIOLOGY OF 



form a wide, capacious tiamk, the renal 

 vein. This is supplied with valves, not all 

 of which are perfect. At the opening of 

 each renal vein into the cava is a semi- 

 lunar flap, overlapping the posterior part. 



The nerves of kidneys are numerous, 

 and derived from the renal plexuses of the 

 sympathetic ; they accompany the vessels 

 with which they penetrate thek respective 

 organs. 



Lymphatics may be seen issuing from 

 the hillus of the kidney ; they enter some 

 lymphatic glands there situate, and then 

 convey the lymph into the receptaculum 

 chyli. 



SUPRA RENAL CAPSULES. 



These bodies, also called capsulsB supra- 

 renales, seu atrabilariae, are two in num- 

 ber, and belong to the class vascular 

 glands, whose office is very indefinitely 

 known. 



They are situated one on each side of 

 the spine, across the duection of the renal 

 vessels. Their attachments are effected by 

 vessels, as well as by the peritoneum, on 

 their inferior sm-face, connecting them to 

 the corresponding kidney and around to the 

 spine. 



The shape of the supra-renal bodies is 

 much the same on either side, being that 

 of a slightly bent ellipsis. They vary 

 from three to four inches in length, and 

 from one and a half to two inches in 

 breadth. 



Their concave border corresponds to the 

 renal vessels, as well as to the anterior 

 mesenteric arteries. The convex border is 

 in contact with the inner margin of the 

 Iddney. The anterior extremity of the 

 right one is in connection with the right 

 hepatic lobe, whUst its inferior surface is 

 in connection with the commencement of 

 the colon. The left supra-renal capsule is 

 related anteriorly to the pancreas, and infe- 

 riorly to the transverse colon. 



The peritoneal coat of the supra-renal 

 capsules is merely confined to their inferior 

 surface. The proper substance of the 

 organ is enclosed in a fibrous or albugine- 



ous coat, which forms a distinct covering 

 externally, and becomes continuous as 

 sheaths to vessels internally. 



On cutting horizontally across a supra- 

 renal capsule, it is found to consist of an 

 outer cortical and an internal medullary 

 substance. The cortical substance is a 

 brownish yellow, due to fat contained in 

 vesicles, which, according to Professor Hein- 

 rich Frey, are smaller toward the surface 

 than more internally. The meduUary sub- 

 stance has a greyish aspect, and vessels are 

 apparent in it, as also a yellow tinge, due, 

 according to the above-named author, to 

 similar vesicles, as in the cortical substance, 

 only much scantier in fat. 



The arteries of the supra-renal capsules 

 are offsets of the renals and anterior mesen- 

 teric, as well as of the aorta, but very 

 variable in number and origin. They are, 

 however, always abundant, and enter the 

 organ principally at its concave border. 



The veins are larger than the arteries, and 

 pour their contents on the left into the renal 

 vein, and into the vena cava on the right. 



The nerves of the ' supra-renal capsules 

 are very abundant, and derived from the 

 renal plexus. Professor Frey states, that 

 in the horse, gangloin corpuscles constitute 

 one of the structural elements of the nervous 

 tissue in this situation. 



URETERS. 



The ureters, one to each kidney, are con- 

 duits between the kidneys and the bladder, 

 for the passage of urine. Their caliber is 

 various, being about one-third of an inch 

 broad, but getting narrower posteriorly. 



As the ureters issue from the kidneys, 

 they converge towards the spine; then pro- 

 ceed suddenly backward, till they reach the 

 brim of the pelvis, having thus greatly 

 diverged ; here they converge again, passing 

 downward and backward to reach the sides 

 of the body of the bladder, which they 

 pierce. 



In their course, the ureters are attached to 

 the kidney and psoas parvus by loose cellu- 

 lar tissue, and by the peritoneum, which 

 suspends them, by being stretched across 



