Furthermore, the female must provide a reproductive system compatible with sperm transport, capacitation, and fertilization of the oocytes, embryo and fetal development, and finally birth of healthy young.
The cervix, the tip of the uterus, projects into the vagina and secretes mucus that enhances sperm transport; estrogens are thought to regulate the flow and thickness of these mucous secretions.
Heat shock protein A8 (HSPA8) is a highly conserved member of the Hsp70 family, which is expressed in oviductal cells, translocated into oviductal fluid, and becomes attached to the sperm surface during sperm transport.
Sperm management by females involves a wide range of processes, including liberation of sperm from a spermatophore, digestion of male secretions and sperm, transport of sperm to and from the spermatheca, maintenance of stored sperm, and fertilization.
One idea is that it may facilitate sperm transport.
Adenomyosis is a significant factor of sterility in these patients, presumably by impairing uterine sperm transport [37].
The hypothetical underlying mechanisms for infertility due to IUAs are obstruction of sperm transport into the cervix, impaired embryo migration within the uterine cavity, or failure of embryo implantation due to endometrial insufficiency [1].
Kunz et al. [26] concluded that with a prevalence of up to 90%, uterine adenomyosis is significantly associated with pelvic endometriosis and constitutes an important factor of sterility in endometriosis presumably by impairing uterine sperm transport.
And as penises are ultimately sperm transporting units, males must fit females as best they can.
The function of the pollen tube is to deliver sperm, transported as cargoes in its cytoplasm, to the female gametophyte for fertilization.
Altogether, these data indicate that either the sperm transported both the GC and the PCL or that the GC duplicated immediately after fertilization and before the completion of maternal meiosis II.
