EXCRETORY AND REPRODUCTIVE SYSTEMS 



199 



in the form of a papilla. In the cortical substance are hundreds 

 of renal corpuscles, each composed of a ball of capillaries (Fig. 99) 

 enveloped by the invaginated enlarged extremity of a tubule 

 which carries away the urine by a tortuous course to the papilla 

 (Fig. 99). In the renal corpuscles the water and other mineral 

 substances of the urine are extracted from the blood by means 

 of the epithelial cells forming 

 the inner wall of the capsule 

 of Bowman. These urinary 

 products pass through the 

 proximal convoluted tubule and 

 the loop of Henle to the distal 

 convoluted tubule, where they 

 are mingled with the urea ex- 

 tracted from the blood by the 

 columnar epithelial cells of the 

 tubule. From this point the 

 excretions flow into the collect- 

 ing tube which empties into the 

 pelvis at the papilla. In a pre- 

 pared microscopic section of the 

 kidney, these renal corpuscles 

 and renal tubules may be seen 

 with a microscope magnifying 

 about 200 diameters. 



The ureter is a small tube 

 leading from the pelvis of each 

 kidney along the dorsal aspect 

 of the abdominal cavity to the 

 dorsal and caudal end of the 

 bladder. 



The bladder is the sac for re- 

 taining the urine. Itliesventrad 



to the rectum, a little to the right of the median line, being held 

 in place by the ligamentum suspensorium, a fold of the perito- 



FiG. 97. — Ventral Aspect of Fe- 

 male Urino-genital System with 

 THE Bladder Pulled to One Side. 



a. Entrance of the urethra into the 

 vestibule; ao, aorta; bl, bladder; cl, 

 clitoris; en, cornu or horn of the 

 uterus; fl. Fallopian tube, the left 

 one is cut off; fm, fimbriated ex- 

 tremity of the Fallopian tube; kd, 

 kidney; /, ovarian ligament; ov, 

 ovary; ra, renal artery; rv, renal 

 vein; re, rectum; ur, ureter; ut, body 

 of the uterus; uth, urethra; vc, vena 

 cava; vg, vagina; vs, vestibule. 



