ENDOCRINE GLANDS AND THEIR FUNCTIONS 671 



Conversely it has been noticed that injections of extract from an- 

 terior pituitary raises blood calcium in some species because of in- 

 creased activity of the parathyroids. 



Too great an activity on the part of the parathyroid glands results 

 in a decalcification of the bones, and an increased content of calcium 

 in the blood and in the excretion of the kidneys. The final result of 

 this softening of the bones may cause serious disfiguration and stunt- 

 ing of the body. Accompanying these results are flabbiness of the 

 muscles, decreased irritability of the nervous system, and other un- 

 favorable conditions. These may be remedied by the removal of a 

 portion of the parathyroids. 



The Suprarenal Bodies 



Lying close to and slightly anterior to the kidneys are two small yel- 

 low or reddish masses of tissue, which play a prominent role in the 

 regulation of the body and one of such complexity that much is yet 

 to be learned concerning its method of functioning. These adrenal 

 glands, or suprarenal bodies, are made up of an inner and an outer 

 portion, the medulla and cortex respectively. The former secretes a 

 substance designated as adrenalin (epinephrine or adrenin), which 

 acts upon various organs and raises the level of their functioning. 

 Adrenalin, at times of excitement or emergency, may cause con- 

 striction of blood vessels, increased rate of heartbeat, a greater 

 discharge of glucose from the liver to provide additional energy, 

 erection of hairs, stimulation or inhibition of the various visceral 

 muscles, etc., to provide greater efficiency. The range of control of 

 the medullary portion of the adrenals is thus wide and complex, 

 definitely interrelated with the functions of the sympathetic nervous 

 system, with other endocrine glands, and numerous processes of the 

 body, so that its true importance is difficult to estimate. Adrenalin 

 has been obtained from various animals for use in the treatment of 

 certain disorders, as an anesthesia in minor operations, and to stop 

 small hemorrhages. It has also been successfully employed in the 

 relief of asthma and similar troubles. 



A hormone kno^vn as cortin has been isolated from the suprarenal 

 cortex, and, while the removal of this portion of the adrenals results 

 in death, the exact functions of the hormone produced therein are 

 not entirely understood. It does relieve the condition known as 

 Addison's disease. There is, without doubt, a close relationship 

 between the cortex and sexual development; and some workers 



