392 



THE URINE. 



1000 



adrtM the interstitial stroma consists almost entirely of branched corpuscles, which anastomose 

 with each other [There is also a small quantity of delicate fibrous tissue around Bowman s 

 capsule, and along the course of the arteries. The connective-tissue often plays an important 

 role in pathological conditions of the kidney, as interstitial nephritis.] The outer layers of the 

 capsule ot the kidney are composed of dense bundles of fibrous tissue, while the deeper layers 

 are more loose, and send processes into the cortical layers. The capsule is easily stripped off. 

 None of the secretory substance is removed with it. Under the capsule m the human kidney, 

 there is a thin plexus of non-striped muscular fibres. At the hilum it becomes continuous 

 with the outer fibrous coat of the dilated upper end of the ureter. Smooth muscular fibres also 

 oscur in a sphincter-like arrangement round the apex of each papilla, while others proceed from 

 the pelvis between the pyramids along the blood-vessels (Jardet). The fat surrounding the 

 kidney is united to the latter partly by blood-vessels and partly by bands of connective- 



tissue. [The subcapsular layer of the cortex, 

 and a thin layer next the boundary zone (fig. 

 242, a, a), are devoid of Malpighian corpuscles.] 

 [Development of a Malpighian Capsule. The 

 upper end of the urinary tubule is dilated and 

 closed, and into it there grows a tuft of blood- 



1010 vessels (a) pushing one layer of the tube before 



it (b), hence the capillaries become invested by 



it, just as an organ is surrounded by a serous sac, 



,fl * so that one layer the reflected one (b) of the 



tubule is closely applied to the blood-vessels, 



1080 while the other (c) lies loosely over it with a 



space between the two (fig. 248).] 



1040 255. THE URINE. Physical 

 Characters. A knowledge of the com- 

 position of this secretion is of the greatest 

 -, value to the physician and surgeon. 



1. The quantity of urine passed by an 

 100 adult man in twenty-four hours is between 



1000 and 1500 cubic centimetres, or about 

 50 ozs., and in the female 900 to 1200 

 c.c. The minimum is secreted between 

 2 to 4 a.m., and the maximum between 2 

 to 4 p.m. ( Weigelin). 



The amount is diminished by profuse sweat- 

 ing, diarrhoea, thirst, non-nitrogenous food, 

 diminution of the general blood-pressure, after 

 severe haemorrhage, and in some diseases of the 

 kidneys. The minimum, which may be normal, 

 is 400 to 500 c.c. It is increased by increase of 

 the general blood -pressure, or of the pressure 

 within the area of the renal artery, by copious 

 drinking, contraction of the cutaneous vessels 

 through the action of cold, the passage of a 

 large amount of soluble substances (urea, salts, 

 Fig. 248.-Development of a glomerulus and ami Sl, g ar ) into the urine, a large amount of 

 Malpighian capsule, a, cafillary ; b, vis- nitrogenous food, as well as by various drugs, 

 ceral ; c, parietal layer of capsule. c }\ as digitalis alcohol, squills. Alter taking 



Fig. 249.-Graduated cylinder and flask f or ?nids charpd with CO ? the amount of urine is 

 measuring the amount of urine. increased during the following hours [Quincke) 



Fig. 250. frinonieter n e 8ecre tion is influenced directly by the 



nervous system, as in the sudden polyuria fol- 

 lowing, nervous excitement, such as hysteria, [when the person usually passes a large amount 

 of very pale-coloured urine] ; after an epileptic attack, and also after pleasurable excitement 

 (Bcnckc). We may have polyuria unaccompanied by the presence of sugar in the urine, which 

 follows injury to a certain part of the floor of the fourth ventricle (CI. Bernard). The urine is 

 measured in tall graduated cylindrical vessels (fig. 249). [In estimating the quantity of urine 

 ltassed, the patient must, of course, be directed always to empty his bladder at a particular 

 hour, and collect the urine passed during the next twenty-four hours.] 



2. The specific gravity varies, as a mean, between 1015 and 1025 ; the mini- 



Fig. 249. 



Fig. 250. 



