COORDINATION AND BEHAVIOR 



553 



Third ventricle (cavity) 

 of brain 



Optic chiasma 



Pituitary 



(hypophysis) 



Infundibulum 



Parathyroids 

 Anterior lobe 



ntermediate lobe 

 Posterior lobe 



,....-..Vv.-.-.V... 



.^•i*-.' 



oil 



^ 



^> — \ 



Thymus 



Pancreatic 

 d cells 



Adrenal 

 Duodenum 

 (not shown) 



Islets of 

 Langerhans 

 (in pancreas) 



"Ovary 



-Placenta 

 (not shown) 

 Pancreatic duct 



Diagram of lobes 

 of pituitary gland 



/ 



■Testis 



Section of pancreos 



Figure 398. Left, a diagram to show the approximate location of some of the endocrine 

 glands in man. Although the pineal body and thymus are included, they are not known definitely 

 to be organs of internal secretion. Right, section of a pituitary gland showing lobes and microscopic 

 structure of the pancreas. 



bone. It consists of an anterior lobe and a 

 posterior lobe. The posterior lobe secretes 

 two or more hormones, collectively called 

 pituitrin. Injection of pituitrin into the cir- 

 culatory system raises the blood pressure, 

 decreases the amount of urine formed, and 

 causes the contraction of smooth muscles, 

 especially those of the uterus, and the con- 

 tractile elements in the mammary glands 

 which cause the "let down" of milk. 



The anterior lobe secretes several hor- 

 mones. These (1) control skeletal growth, 

 (2) stimulate the growth of the gonads and 

 maintain them in functional condition, (3) 

 stimulate milk secretion, (4) stimulate the 

 thyroid, and (5) stimulate the adrenal 

 cortex. An excessive amount of secretion 



of the growth hormone in the young stimu- 

 lates development of the long bones result- 

 ing in giantism; when this occurs in adults, 

 the bones, especially of the limbs and face, 

 become thickened, resulting in acromegaly. 

 The pituitary also secretes a hormone which 

 increases the sugar content of the blood, 

 thus having effects opposite to those of 

 insulin. 



The influence of the pituitary gland on 

 other endocrine glands gives it the name of 

 the "master gland." 



Ovary 



Several hormones are secreted by the 

 ovary. Estrogens are formed in the Graafian 



