SECT. 188.3 STROMA AND VESSELS OF THE KIDNEY 



413 



Fig. 172. 



UH 



Transverse section through some straight 

 tubules of the cortex of the human kidney ; 

 magnified 350 times, a. Transverse sections 

 of urinary tubules, of which the membrann 

 propria is alone preserved; 6. the same, 

 where the epithelium is still present ; c. 

 stroma of areolar tissue, with elongated nu- 

 clei ; d. space, which has contained a Mal- 

 pighian corpuscle. 



All the vessels and nerves are supported by areolar tissue, which 

 serves, at the same time, as a 

 stroma for the secretory struc- 

 tures, and is much more developed 

 in the pyramidal than in the cor- 

 tical substance. On the surface 

 of the kidney, it frequently be- 

 comes condensed, and forms a 

 very distinct membrane, of o - oi'" 

 to o*02'" in thickness, which is 

 only loosely connected with the 

 fibrous capsule; here it assists in 

 supporting the superficial capillary 

 network, and is connected with 

 the internal stroma by numerous 

 delicate processes. 



Virehom has lately put forth some 

 views on the distribution of the renal 

 vessels, which differ from those usually 

 received — those of Arnold excepted. 

 While Virehom admits that the ar- 

 teries of the pyramids, or their capillaries, are prolonged from the efferent 

 vessels of the Malpighian bodies, he also maintains that the arteriolae 

 rectfe have no such origin, but are derived directly from the renal arteries, 

 especially from those branches which bear the Malpighian coils. Now, 

 neither in the lower mammalia nor in man, can it be doubted that all 

 the glomeruli on the margins of the pyramids give their efferent vessels as 

 true arteriole rectae ; but I am not prepared wholly to deny Virchow's position 

 without a re-examination of the question. Possibly it may be true, that in 

 man some of the arteries of the pyramids are given off direct from the renal 

 arteries, although, in the amphibia, and other lower animals, there is no ques- 

 tion that the whole blood of the kidney does pass through the glomeruli. The 

 fact, well known to anatomists, that in common injections of whole bodies the 

 vascular coils often are injected, while the pyramids are quite free, argues 

 little for any direct passage of arterial blood into the pyramids. It may be 

 remarked, too, that Virehom gives the diameter of these arteriolce in question 

 as three times greater than has been stated above, even up to 0-03"' to 0-04'". 



In inflammation and exudations into the kidney, the stroma frequently 

 becomes thickened so considerably, that it is apparent on the most superficial 

 observation, and even more or less displaces the urinary tubules. The parts 

 newly added to it consist chiefly of a fibrinous exudation, in different stages 

 of transition into areolar tissue, partly, also, of forms which belong to areolar 

 tissue in process of normal formation, such as plastic cells. These new for- 

 mations often appear in the interior of the Malpighian corpuscles (Frerichs), 

 usually in the form of concentric depositions, frequently very thick, which 

 compress the afferent and efferent vessels, and thus produce atrophy of the 

 glomerulus, so that the secretion of urine becomes very materially impaired. 



