240 



PHYSIOLOGY 



CHAP. 



anterior face against the ventral wall, almost always with the 

 fundus inclined to the right. 



The cervix of the uterus takes part in the hypertrophy of 

 pregnancy and undergoes the same changes as the body ; but the 

 rnucosa of the cervical canal is not transformed into decidua, but 



preserves its epithelium intact. 

 The mucous glands of the cervix 

 secrete during gestation a tough, 

 transparent mucus, which closes 

 the uterine cavity like a stopper. 



From the seventh month on- 

 wards the projection into the 

 vagina of the cervix of the uterus, 

 the so-called tench mouth, gradu- 

 ally disappears, so that if the 

 fornix of the vagina be explored 

 with the finger, the external 

 orifice of the uterus is reached 

 directly. It was formerly errone- 

 ously believed that as pregnancy 

 advanced the cavity of the uterus 

 increased in size at the expense 

 of the cervical portion ; numerous 

 observations upon cases shortly 

 before parturition have, however, 

 clearly proved that the uterine 

 neck and the cervical canal pre- 

 serve their full length and undergo 

 no change until the beginning 

 of the contractions preceding 

 parturition (Fig. 104). Obviously 

 the so-called destruction of the 

 vestibule is due to the fact that 

 from the seventh month onwards 

 the sinking of the head of the 

 foetus brings greater pressure 

 to bear on the lower segment 

 of the uterus and distends it 

 downwards together with the 

 anterior vaginal fornix. The 



vagina and the vestibule become gradually softer during preg- 

 nancy owing to the venous hyperaemia, which may be recog- 

 nised by the bluish colouring of the mucosa of the vagina and 

 vulva, which finally becomes dark violet, because the venous 

 vessels of these parts form, by their dilatation, a true vascular 

 plexus. 



During the state of gestation, the mammary glands attain 



FIG. 102. Thin section of wall of gravid 

 uterus, near full term, o, submucous 

 layer; 6, middle vascular layer; c, sub- 

 serous layer. The muscular fasciculi are 

 drawn aside in order to show better their 

 course ; in the middle layer numerous 

 lacunae crossed by venous and arterial 

 vessels are visible. 



