3IO 



CHORDATE ANATOMY 



partially surrounds the ovary. The margin of this opening is prolonged 

 into numerous fimbriae which surround the ovary and convey the ova 

 into the uterine tube. A ciliated columnar epithehum lines the tubes, 

 the cilia beating towards the uterus and carrying the ova in that direction. 

 The number of ciUa is greatly increased by the complex folding of the 

 Uning of the tubes. The blood supply of the tubes comes from ovarian 

 and uterine vessels. The nerves are sympathetic. (Fig. 275) 



The Uterus. The uterus is a median pear-shaped organ suspended 

 in the broad ligament. Round and ovarian ligaments form additional 

 supports. The body of the uterus is normally bent forward so that it 

 rests upon the bladder. By a constriction, the isthmus, the uterus is 



NUCLLAR DIVISION 



IMPLANTATION 



FERTILIZATION COMPLETE 

 UNION OF PRONUCLEI 



-CORPUS LUTEUM 



UTERINE TUBE 



SPERMATOZOON 



OVULATION 

 1ST POLAR BOCrV STAGE 



UTERINE GLANDS 



Fig. 275. — Diagram illustrating the passage of the fertilized egg from the ovary to the 

 uterus. The ovum is a week in the tube and three days in the uterus before implanta- 

 tion takes place. (Redrawn after Dickinson's " Sex Anatomy," Williams & Wilkins Co.) 



divided into an upper body and a lower cervix. Its cavity is connected 

 with that of the vagina below and those of the paired uterine tubes above. 



The cavity of the uterus is lined with a simple cihated columnar 

 epithehum, from which numerous tubular glands of unknown function 

 grow down into the underlying connective tissue. This mucous hning, 

 the endometrium, is partly lost during menstruation, with some extravasa- 

 tion of blood. The thick muscular wall of the uterus consists of inter- 

 woven masses of smooth muscle fibers. Uterine and ovarian vessels 

 pro\nde the blood supply. The nerve supply is sympathetic. 



The Vagina. The vagina provides the outlet of the reproductive 

 apparatus. It is a highly distensible muscular canal between two and 

 three inches in length, extending from the lower end of the uterus, the 

 OS uteri, to the vestibule. Previous to sexual congress its external opening 

 is more or less completely occluded by a membranous hymen. The vagina 

 is Uned with squamous stratilied epithehum free from glands. Its 



