1354 



THE URINOGENITAL ORGANS 



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lymphatics. The diameter of the tubule and the size of the cells vary in the different convolutions. 

 The capsule of Bowman is lined with simple squamous cells, and the renal corpuscle has a diameter 

 of 120 to 200 microns; the neck is lined by simple squamous cells, and has a diameter of about 

 15 microns; the proximal convoluted and spiral tubules are lined with irregular columnar cells; 



the lumen of the tubule is irregular and the 

 diameter averages about 40 microns; the descend- 

 ing limb of Henle's loop is lined with simple squa- 

 mous cells, and the diameter is from 10 to 13 

 microns; the loop and ascending limb are lined 

 with regular cuboidal cells, and the diameter 

 averages from 23 to 28 microns; the distal con- 

 voluted tubule is lined with irregular columnar 

 cells, the lumen is irregular, and the diameter 

 about 45 microns; the arched connecting tubule 

 is lined with simple cuboidal cells, and the 

 diameter is about 45 microns; the straight col- 

 lecting tubule is lined by columnar cells, and the 

 diameter increases from 45 to 75 microns; the 

 papillary ducts are lined with tall columnar cells, 

 and the diameter reaches 200 to 30t) microns. 

 The protoplasm of these cells is granular at the 

 basal end, while the luminal end is striated. 



The parts of the kidney in which the various 

 portions of the uriniferous tubules lie are as 

 follows : 



Cortex. In the labyrinth are found the renal 

 corpuscles, the neck, and the proximal and distal 

 convoluted tubules. 



In the medullary rays are found the upper 

 ends of the descending and ascending limbs of 

 Henle's loop, the arched collecting tubules, and 

 the upper ends of the straight collecting tubules. 



Medulla. Here are found the lower ends of 

 the descending and ascending limbs of Henle's 

 loop, the loop, the straight collecting tubules, and 

 the papillary ducts. 



Tne Renal Bloodvessels. The kidney is 

 plentifully supplied with blood by the renal artery 



FIG. 1099. Diagram of three uriniferous tubules 

 and their relation to a collecting tubule. A. Of a 

 tubule, the Malpighian corpuscle of which is situated 

 in the lowermost portion of the cortex. B About 

 the middle of the cortex. C. In the outer portion 

 of the cortex, m. Malpighian corpuscle v Vessel 

 -+a xr^^ij pc p rox j ma i convoluted portion, 

 nt. dl. Descending limb. al. As- 

 jf the loop of Henle. dc. Distal 



, 



porta. n. Neck. 

 es. End segme 



cending limb o . . 



convoluted portion. j. Junctional tubule 

 Collecting tubule. (Huber.) 



FIG. 1100. Longitu- FIG. 1101. Longitudinal 

 dinal section of Henle's section of straight tube. a. 

 descending limb. a. Cylindrical or cubical epi- 

 Membrana propria. b. thelium. b. Membrana pro- 

 Epithelium, pria. 



(Figs. 1088 and 1096), a large branch of the abdominal aorta given off at the level of the articular 



k between the first and second lumbar vertebrae. The importance of the kidney as an excre- 



ory organ is evidenced by the fact that the artery is three times as large as is necessary for the 



nutrition of an organ of the size of the kidney. Previously to entering the kidney, each artery 



