56 



PHYSIOLOGY FOR NURSES 



the central nervous system connected by at least two 

 nerves with a given gland or other structure. On nerve 

 conveys impulses from center to organ and is called an 

 efferent nerve; the other carrying impulses from pe- 

 riphery to center, is called an afferent nerve. Thus if a 

 little salt be placed on the tongue a message is sent to 

 the center which controls secretion which acknowledges 

 it by sending a message to the gland cells to begin se- 

 cretion. Two other nerve impulses, however, are 



Cardiac Orifice 



(Esophagus 



Funclus 



Great Curvature 



Ductus Communis.- 

 Choledochus 



Duct of Wirsung 



Duodenum 

 Fig. 12. The stomach and duodenum opened. (Buchanan's Anatomy.) 



needed before the gland can function properly one in- 

 creasing and one decreasing the blood supply. These 

 are called vasodilator and vasoconstrictor fibers. The 

 function of the first is to increase the amount of blood 

 on which the gland can act. Vasodilator fibers are car- 

 ried along with the secretory fibers in the cranial nerve 

 called chorda tympani, while vasoconstrictor fibers come 

 from the sympathetic. Afferent fibers are carried by 



