STEUCTUKE AND FUNCTIONS OF THE URETEE. 



431 



3. As ligature of the ureters produces a comatose condition in those animals which excrete 

 chiefly uric acid in the urine e.g., birds and snakes (Zalesky) it is possible that other sub- 

 stances may produce the poisonous symptoms. The injection of kreatinin causes feebleness 

 and contraction of the muscles in dogs {Meissner). Bernard, Traube, and more recently Feltz 

 and Ritter ascribe the symptoms to an accumulation of the neutral potassium salts in the blood 

 (. 54). The injection of kreatin, succinic acid {Meissner), uric acid, and sodic urate (Eanke), is 

 without effect. Schottin and Oppler ascribe the results to an accumulation of normal or 

 abnormal extractives. It is possible that several substances and their decomposition-products 

 contribute to produce the result, so that there is a combined action of several factors, but 

 perhaps the retention of the potash salts plays the most important part. 



The direct application of some urinary substances (kreatinin, kreatin, acid potassic phosphate, 

 urates) to the surface of the cerebrum causes all the symptoms of uraemia. Urea is inactive, 

 and slightly active are ammonium and sodic carbonate, leucin, Nad, KC1 {Landois). 



[Alkaloids in Urine. Human urine, and especially febrile urine, when injected under the 

 skin of frogs or rabbits, acts as a poison, and even causes death, by arresting the respiration. 

 The alkaloids seem to be formed by the action of vegetable organisms in the intestine, whence they 

 are absorbed into the blood and pass into the urine ( 116). Urine rendered colourless by char- 

 coal loses half its toxic power, and the poisonous substance is not volatile, and even resists boiling. 

 These alkaloids are increased, in the urine in typhoid fever, pneumonia, but not in diabetes.] 



Ammoniaemia. When urine undergoes the alkaline fermentation within the bladder, and 

 ammonium carbonate is formed, the ammonia may be absorbed and produce this condition. 

 The breath and excretions smell strongly of ammonia ; the mouth, pharynx, and skin are very 

 dry ; there is vomiting, with diarrhoea or constipation, while ulcers may form in the intestine. 

 The patient rapidly loses flesh, and death occurs without any disturbance of the mental 

 faculties. 



Uric Acid Diathesis. When too much nitrogenous food, too much of any alcoholic fluid is 

 persistently used, and little muscular exercise taken, especially if the respiratory organs are in- 

 terfered with, uric acid may not unfrecpuently accumulate in the blood (Garrod). It maybe 

 deposited in the joints and their ligaments, especially in the foot and hand, giving rise to pain- 

 ful inflammation, and forming gout-stones or chalk-stones. The heart, liver, and kidneys are 

 rarely affected. The tissues near these deposits undergo necrosis. 



278. STRUCTURE AND FUNCTIONS OF THE URETER. Mucous Membrane. The 



pelvis of the kidney and the ureter are lined by a mucous membrane, consisting of connective- 

 tissue, and covered with several 



layers of stratified " transitional " - r^C^^r 6 ^ Adventitia. 



epithelium (fig. 290). The cells 

 are of various shapes, those of the 

 lowest layer being usually more or 

 less spherical and small, while 

 many of the cells in the upper 

 layers are irregular in shape, often 

 with long processes passing into 

 the deeper layers. 



Sub-mucosa. Under the epi- 

 thelium there is a layer of adenoid 

 tissue {Hamburger, Chiari), which 

 may contain small lymph-follicles 

 [embedded in loose connective- 

 tissue]. In the pelvis of the kidney 

 and ureter there are a few small 

 mucous glands lined by a single 

 layer of columnar epithelium 

 {Unruh, Egli). 



The muscular coat consists of an 

 inner somewhat stronger layer of 

 longitudinal non-striped fibres, and 

 an outer circular layer (fig. 289). * Fig. 289. 



In the lowest third of the ureter Transverse section of the lower part of human ureter, x 15. 

 there are in addition a number of e, epithelium ; t, tunica propria ; s, sub-mucosa ; I and r, 

 scattered muscular fibres. All longitudinal and circular fibres, 

 these layers are surrounded and 



supported by connective-tissue. The outer layers of the connective-tissue form an outer coat or 

 adventitia, which contains the large vessels and nerves. The various coats of the ureter can 

 be followed up to the pelvis of the kidney, and to its calices. The papilla? are covered only by 

 the mucous membrane, while the muscular layer ceases at the apex of the pyramids, where 

 they are disposed circularly, to form a kind of sphincter muscle for each papilla {Henle). 







