382 ABDOMEN 



Kidney Capsule and Kidney Substance. The kidney is 

 invested by a strong fibrous capsule, which can be easily 

 stripped from its surface. Divide the capsule along the lateral 

 margin of the organ and peel it off towards the hilum. 

 There it enters the renal sinus, lines the walls of the sinus, 

 and becomes continuous with the sheaths of the vessels 

 entering the gland, and also with the external coats of the 

 calyces of the ureter. 



Examine the manner in which the ureter or duct is con- 

 nected with the kidney. As it approaches the hilum it expands 

 into a wide funnel-shaped portion called the pelvis (Fig. 183). 



The pelvis enters the sinus and divides into two, or 

 perhaps three, large primary branches, and those again break 

 up into a large number of short, stunted secondary divisions 

 called calyces, which are attached to the walls of the sinus. 



Dissection. Divide the kidney into anterior and posterior 

 parts. Take a large knife and carry it through the kidney from 

 the lateral border to the hilum, parallel with and midway between 

 the two surfaces. Then examine the cut surfaces and the 

 contents of the sinus. 



An examination of the cut surface of the kidney will show 

 that its substance is arranged in two parts a medullary and 

 a cortical. The medullary portion consists of dark-coloured, 

 faintly striated pyramidal masses, the bases of which are 

 directed towards the periphery, whilst their apices are free 

 and project into the sinus. On the sinus wall the apex of 

 each medullary pyramid forms a prominent mamillary 

 projection, called a renal papilla, which projects into one of 

 the calyces of the pelvis of the ureter (Fig. 182). If the 

 kidney is squeezed, fluid will be seen to exude from the 

 papillae, showing that the tubuli uriniferi open upon their 

 surface. The number of pyramids and renal papillae varies 

 from eight to twenty. Usually there are more than twelve. 

 A single calyx of the ureter may surround one, two, or even 

 three renal papillae ; it receives the urine as it issues from the 

 papillary ducts which open on their surfaces. The cortical 

 substance constitutes the peripheral part of the gland, and also 

 sends prolongations inwards between the pyramids. The 

 prolongations of the cortex are called the columns renales 

 (O.T. columns of Bertin}. 



Ureter. The ureter is the duct which carries the urine 

 from the kidney to the bladder. The relations of its ex- 



