THE MALE AND FEMALE REPRODUCTIVE ORGANS 1129 



being called pollutions. Among the nerves concerned in the acts of 

 erection and ejaculation may be mentioned the nervus pudendus, 

 nervus erigens, and nervus ileo-inguinalis. The first sends one of 

 its branches, the nervus perinei, to the ischio and bulbo-cavernosi, 

 the bulbus urethrse and the mucous membrane of the upper urethra. 

 This nerve, therefore, is the one controlling ejaculation. Another of 

 its branches, the nervus dorsalis penis, innervates the skin, prepuce, 

 corpora cavernosa, and outer portion of the urethra. This nerve, 

 therefore, conveys sensory impulses from the largest part of the penis. 

 The nervus erigens, as has been stated above, is chiefly vasomotor in 

 its function, while the ileo-inguinalis innervates the base of the penis. 



The Ovaries. — The essential reproductive organ of the female is 

 represented by the ovaries, two flattened, more or less almond-shaped 

 bodies which are situated in the upper part of the pelvic cavity in a 

 slight depression in the obturator muscle. Although subject to con- 

 siderable fluctuations, the adult ovary measures 2.5 to 5 cm. in length, 

 1.5 to 3 cm. in breadth, and 0.6 to 1.5 cm. in thickness. In cross- 

 section each organ is seen tabe made up of two portions, a cortex and 

 a medulla. The former varies in thickness, becoming thinner with 

 advancing years, and consists of connective tissue containing isolated 

 primordial and Graafian folHcles. The- central medullary portion is 

 made up of loose connective tissue containing large numbers of blood- 

 vessels and smooth muscle cells. ^ 



In the child, the greater portion of the ovary is composed of cortical 

 substance which is closely packed with primordial follicles in different 

 stages of development. This is also true of the ovary of young 

 women, but the follicles are then more widely separated from one an- 

 other by layers of connective tissue of varying thickness. Each 

 follicle consists of an oocyte surrounded by a single layer of epithelium 

 and measuring from 48 to 69 ju in diameter. At birth each ovary 

 contains at least 100,000 oocytes, while at puberty it embraces only 

 from 30,000 to 40,000; but even this number is more than sufficient to 

 supply the necessary ova for fertilization, because only one of them is 

 discharged 'during each menstrual period. It may also happen that 

 one of these follicles contains two and more distinct ova, a fact which 

 has been made use of in explaining multiple pregnancies. 



These primordial follicles eventually develop into the mature Graafian follicle, 

 a process which begins at birth and does not cease until the menopause has termi- 

 nated the sexual life. To begin with, the spindle-shaped epithelial investment is 

 changed into a single layer of cuboidal cells which then proliferate rapidly until 

 the central ovum has become enveloped by several layers of epithelial cells. By the 

 degeneration of certain ones of these cells a space is eventually formed around the 

 ovum which becomes filled with fluid, the liquor folliculi. The ovum itself grows 

 larger constantly and is gradually pushed to one side, where it becomes surrounded 

 by a layer of cells, forming the discus proligerus. Its nucleus undergoes important 

 changes which finally terminate in the formation of the first polar body, a deposi- 

 tion of yolk granules in the cytoplasm, and the formation of a thin investment, the 



^ Clark, Contrib. to the Science of Med., Johns Hopkins Univ., 1900. 



