ANATOMY IN A NUTSHELL. 469 



Behind. — (1) The last rib, (2) Diaphragm, (3) Quadratus Lumborum, 

 (4) Psoas magnus. (Plate VIII.) 



The organs of the urinary system are, (1) the two kidneys, which form the 

 urine from the materials furnished by the blood; (2) the ureters, which con- 

 vey the urine away from the kidneys; (3) the bladder in which the urine is 

 stored until it is discharged, and (4) the urethra, a tube through which the 

 urine passes from the bladder. 



The kidney is a glandular structure whose function is the purification of 

 the blood by the excretion of the urine. It is held in position by its vessels, 

 the peritoneum and the abundant fatty tissue. This fatty tissue forms the 

 " adipose capsule. ' ' 



The hilum of the kidney is the place on the median side of the kidney. 

 corresponding to the place of the scar on the bean. It is where the ureter goes 

 out and the vessels and nerves enter. The capsule of the kidney is a smooth 

 fibrous membrane closely investing the kidney and forming its outer coat. 



Floating kidney is one which has become loose and displaced hi the abdo- 

 men. Surgical kidney is a term somewhat loosely applied to nephritic condi- 

 tions, secondary conditions to mischief farther down in the urinary tract, but 

 especially to suppurative pyelonephritis arising from cystitis. 



The pelvis or sinus of the kidney is the concavity or re-entrance at the hilum 

 of the kidney. The calices of the kidney are cup-like or infundibuliform be- 

 ginnings of the ureter in the pelvis of the kidney surrounding the apices of the 

 Malpighian pyramids, each usually receiving more than one pyramid. There 

 are from seven to thirteen such calices, converging and uniting in the infundi- 

 bula, which in turn combine to form the pelvis. The infundibula of the kidney 

 are, (a) the calices; (b) the two or three main divisions of the pelvis of the 

 kidney formed by the confluence of the calices. 



The apices of the Malpighian pyramids, also called mamillae, are the 

 papillse of the kidney. The Malpighian pyramids are pale-reddish conical 

 masses forming the medullary part of the kidney, whose apices project into the 

 calices of the pelvis of the kidney, and are called papillae. The Malpighian 

 corpuscles or bodies are the glomeruli of the kidney surrounded by its capsule. 

 These form the terminations of the branches of the uriniferous tubules, occur 

 in the cortical substance of the kidney, and are about in 1 ,,,, of an inch in dia- 

 meter. They are formed of the expanded end of the tube invaginated by the 

 bunch of blood vessels constituting the glomerulus which thus are embraced 

 in a double epithelial sac, and the blood is separated from the lumen of the 

 tubule by the vascular wall and the epithelium of the inner layer of the capsule. 



The Malpighian tuft is the glomerulus or vascular network or plexus in a 

 Malpighian body. Marcello Malpighi (1628-94) was an Italian anatomisl and 

 physiologist. 



The cortical substance of the kidney is the outer part of the kidney sub- 

 stance which contains the glomeruli. The columns of Bertin are named after 

 E. F. Bertin, a French anatomist (1712-81). They are the prolongations in- 

 ward of the cortical substance of the kidney between the pyramids. 



