The development of the human body; a manual of human embryology . .- ~-z ,,?£.%< °V-u i$3v m. 77zy_ ! , SS^?5?F* 4%.? j-Z Fig. 9.—Section through Portion of an Ovary of an Opossum(Didelphys virginiana) showing Ova and Follicles in VariousStages of Development. b, Blood-vessel; dp, discus proligerus; mg, stratum granulosum; o,ovum; s, stroma; th, theca folliculi. in the ovarian stroma, and an inner one, the theca interna,composed of numerous spherical and fusiform cells. Boththe thecse are richly supplied with blood-vessels, the thecainterna especially being the seat of a very rich capi
The development of the human body; a manual of human embryology . .- ~-z ,,?£.%< °V-u i$3v m. 77zy_ ! , SS^?5?F* 4%.? j-Z Fig. 9.—Section through Portion of an Ovary of an Opossum(Didelphys virginiana) showing Ova and Follicles in VariousStages of Development. b, Blood-vessel; dp, discus proligerus; mg, stratum granulosum; o,ovum; s, stroma; th, theca folliculi. in the ovarian stroma, and an inner one, the theca interna,composed of numerous spherical and fusiform cells. Boththe thecse are richly supplied with blood-vessels, the thecainterna especially being the seat of a very rich capillarynetwork. Internal to the theca interna there is a trans-parent,^ thin, and structureless hyaline membrane, within THE OVUM. 3 5 which is the follicle proper, whose wall is formed by alayer of cells termed the stratum granulosum (Fig. 9, tng)and inclosing a cavity filled with an albuminous fluid, theliquor folliculi. At one point, usually on the surfacenearest the center of the ovary, the stratum granulosum <S MM. %m :?-. c w I II ;i>^ Fig. 10.—Ovum from Ovary op a Woman Thirty Years op Age. cr, Corona radiata; «, nucleus; p, protoplasmic zone of ovum; ps, peri- vitelline space; y yolk; zp, zona pellucida.—(Nagel.) is greatly thickened to form a mass of cells, the discusproligerus {dp), which projects into the cavity of the folli-cle and encloses the ovum (0). Usually but a single ovumis contained in any discus, though occasionally two oreven three may occur. 36 THE DEVELOPMENT OF THE HUMAN BODY. The cells of the discus proligerus are for the most partmore or less spherical or ovoid in shape and are arrangedirregularly. In the immediate vicinity of the ovum,however, they are more columnar in form and are ar-ranged in about two concentric rows, thus giving a some-what radiated appearance to this portion of the discus,which is termed the corona radiata (Fig. 10, cr). Imme-diately within the corona is a transparent membrane, thezona pellucida (Fig. 10, zp), abou
Size: 3192px × 783px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectembryol, bookyear1902
