02274naa a2200253 a 450000100080000000500110000800800410001902400540006010000190011424500660013326000090019952015870020865000090179565000170180465000100182165000160183165000200184765000100186765000170187765300200189465300200191470000270193477300590196115219432023-06-05       1950    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.1016/0014-4827(50)90046-22DOI1 aRANDALL, J. T.  aThe microstructure of ram spermatozoa.h[electronic resource]  c1950  aAbstract: The microstructure of the mature ram spermatozoon has been investigated by means of the electron microscope, and has been supplemented by preliminary optical studies. Various fixatives and stains were employed, and extensive use was made of ultrasonics as a means of partial disintegration. The results indicate a more complex structure than has yet been found for other mammalian spermatozoa. The investigation included an examination of the membrane system of the head, and various features such as the equatorial segment, the acrosome cap, the innermost membrane and structures underlying it. The evidence for a skeletal framework of the sperm-head was also discussed. The axial-fibre was found to consist of 12 fibrils, each of which is made up of two filaments surrounded by a doublet coil. The suggestion was put forward that a fibril bundle consisting of 3 pairs of fibrils runs down the whole length of the tail. The main-piece itself was shown to be surrounded by a doublet helix; the tail-end consisted of modified fibrils of the axialfibre, surrounded by a fine doublet-helix of its own. Considerable attention was given to the middle-piece structure where three systems of helices were identified. The complexity of the neck structure was investigated; the junction of the head and middle-piece was found to be partly fibrillar, and partly fibrous and membranous. The continuity of the fibrils from the middle-piece and the fibrils which disappear into the head was established. Provisional membrane systems were described for middle-piece, tail, and tail-end.  aRams  aReproduction  aSheep  aSpermatozoa  aEspermatozóide  aOvino  aReprodução  aHistofisiologia  aHistophysiology1 aFRIEDLAENDER, M. H. G.  tExperimental Cell Researchgv. 1, n. 1, p. 1-32, 1950.