498 



URO-GENITAL SYSTEM. 



vascularization by arteries and veins is required for the nu- 

 trition of the new being undergoing process of development. 

 An increase of the muscular elements is required for the 

 process of expulsion (parturition, or labor) of the new being- 

 when perfectly developed (foetus at full term of pregnancy). 

 It is sufficient to state that this act, like all those heretofore 



Fig. 136. Womb, egg, and membranes.* 



studied, is under the influence of the nervous system ; we shall 

 see here also reflex phenomena analogous to all those which 

 concern expulsion and excretion. The point of origin for these 

 phenomena is normally in the uterus ; but various excitations 



* Vertical section of the womb, containing a developed egg or ovum, a, Neck, 

 filled with a gelatinous plug. 66, Orifice of the Fallopian tubes, cc, Membrana 

 decidua vera. d, Uterine cavity, almost entirely filled with the ovum, ee, Where 

 the decidua vera is continuous with the decidua reflexa. f, Caduca serotina or 

 placenta, g, Allantols. h. Umbilical vesicle and its pedicle in the umbilical 

 cord, t, Amnion. Tc, Decidua reflexa and chorion. 



