PROBLEM 6. Hormo7ies Help Regulate Cell Activities 



bristling of the fur or the ruffling of the 

 feathers. This is caused by the contrac- 

 tion of the microscopic bands of muscles 

 in the skin. In us, this contraction pro- 

 duces gooseflesh. You may have heard 

 of people performing the most amazing 

 feats of strength in a crisis. Can you now 

 explain what occurred in their bodies? 



Physicians make frequent use of the 

 powerful effects of adrenin on the body. 

 In cases of heart failure, it may even be 

 injected directly into the heart in order 

 to stimulate it. Adrenin is also used to 

 help clot blood and to help asthmatics 

 whose breathing tubes are constricted. 



Other hormones in the adrenal gland. 

 The outer portion of the adrenal glands, 

 known as the cortex, is quite different 

 from the part that secretes adrenin. It 

 produces other hormones which affect 

 the body in many different ways and 

 very profoundly. A hormone (cortin) 

 has been extracted. This can be injected 

 into the body when disease of the adre- 

 nal glands would otherwise prove fatal. 



Ductless glands and circus freaks. The 

 giant and the dwarf, the fat man and the 

 bearded lady in the side shows of the 

 circus are all individuals suffering from 

 an abnormal condition of one ductless 



253 



Fig. 243 Both inen are full gruivn. Why did the 

 Diidget stop growing earlier than the man of 

 normal size? (copyright pictures, inc.) 



speeds up growth of the skeleton as was 

 shown by the following experiment. An 

 extract was made of the gland, and this 

 extract was injected into young rats for 

 a period of five or six months. These rats 



gland or another. In these cases the dis- and their controls were carefully weighed 



turbance is of a kind which produces 

 extreme outward changes; many gland 

 disturbances may be just as severe but 

 produce changes which are not visible. 

 Giantism and dwarfism can be directly 

 traced to a disturbance of a small gland 

 which lies at the base of the brain. This 

 is the pituitary (pit-two'i-ter-ree) body. 

 The gland is about as large as a small 

 pea and is in two parts. The front (an- 

 terior) part secretes a hormone which 



and measured. At the end of this time 

 the injected rats had grown to almost 

 twice their natural size and weight. 

 Giant rats were produced. 



In the case of the giant of the circus 

 there is an oversecretion of the pituitar\" 

 hormone while the child is growing. 

 You may have seen people, too, in whom 

 only certain bones are enlarged, the 

 bones of the face and perhaps of the 

 hands and feet. This condition (known 



