240 INTERNAL SECRETION 



those of the splanchnic system, in which it induces power- 

 ful vaso-constriction. In the intact animal the heart may 

 be slowed — a reflex effect due to the increased blood- 

 pressure, but after section of the vagi the beat is much 

 accelerated and augmented. The pupils are dilated and 

 the eyeballs protruded. The sahvary glands are either 

 paralysed or secrete a scanty thick saliva. The intestines 

 are relaxed, but the ileo-csecal sphincter and the sphincter 

 ani are contracted. The body of the bladder is relaxed 

 and the neck of the bladder constricted. In the male the 

 retractor penis is stimulated; in the female the uterus is 

 sometimes stimulated, sometimes inhibited. The bron- 

 chioles are relaxed. The sweat glands are stimulated and 

 the hairs erected. 



The hver is stimulated to increased sugar production, 

 sugar appearing in the urine. It is also said that the 

 recovery of fatigued muscle is accelerated and that 

 coagulation of the blood is hastened. 



The action of adrenahn is not upon the sympathetic 

 nerve endings, for the drug is still effective after degenera- 

 tion of the nerves. Nor is its action upon the peripheral 

 organ itself, since it has no effect upon structures which 

 have no sympathetic supply. It is therefore believed to 

 act upon a receptor substance (neuromuscular junction) 

 lying between the nerve-ending and the organ. 



An increase in the adrenahn content of the suprarenal 

 veins has been shown to occur on experimental stimulation 

 of the splanchnic nerves and during violent emotions. 



Disease of the Swprareniils (Addison's disease). — Usually 

 due to tuberculosis of the glands, it is characterised by 

 low blood-pressure, feeble heart action, abdominal pain, 

 vomiting, extreme muscular weakness, and pigmentation 

 of the skin. It is invariably fatal. 



The circulatory disturbance is referable to deficiency of 

 adrenalin in the circulation. 



Removal of both glands causes muscular weakness, 

 lowering of blood-presssure and cardiac failure, death 



