256 



VETERINARY STUDIES 



floor of the pelvis. These four ligaments all give support to 

 the uterus and hold it in position. 



Openings. — There are three openings into the uterus: one 

 behind, opening into the vagina, i.e. the cervical canal through 

 the cervix; and two in front, for the Fallopian tubes. 



Function. — The function of the uterus is to receive and nour- 

 ish the ovum and mature it after it has been fertilized. 



The ovum attaches to the uterine wall and three covering 

 and supporting membranes are developed around it. These in 



order from without in 

 are the chorion, allan- 

 tois and ammion. Here 

 the fetus develops, re- 

 ceiving oxygen and food 

 materials from the ma- 

 ternal uterine walls, 

 through the surround- 

 ing placental mem- 

 branes. There is no 

 direct circulation from 

 mother to fetus. 



In the cow, sheep, 

 and goat, contact be- 

 tween the mother 's 

 uterus and the chorion 

 is by about 60 to 100 large, rounded button-like bodies called 

 cotyledons, developed from the mucous membranes of the uterus. 

 Over these fit cap-like bodies from the fetal chorion. The mare 

 has a very different relation between fetus and uterus. Her 

 uterine mucous membrane is provided with a very large number 

 of tiny pockets into which fit minute capillary tufts, making a 

 practically continuous contact between uterus and chorion. 



Vagina. — This is a membranous tube which contains much 

 muscular tissue in its walls. 



Structure. — There are three coats: (a) outer, of loose con- 

 nective tissue; (&) middle, muscular; (c) inner, mucous. Close 

 to the cervix, the external surface is covered also by the peri- 

 toneum. 



Location. — The vagina is located in the pelvis between the 

 rectum above and the floor of the pelvis below. It is capable of 

 great dilation to allow the passage of the young at birth. Be- 



Fig. 89. — Bovine Cotyledons. 



A, pedicle of uterine cotyledon; B, B, uter- 

 ine cotyledon; V, fetal cotyledon; E, fetal 

 membrane. 



