A stage in embryonic and placental development, occurring five days after fertilization. After fertilization, the zygote begins to divide, forming a morula—a solid mass of cells that reaches the uterus around day four after fertilization. By day five, a fluid-filled cavity forms between the cells, and the cells arrange themselves through a polarization process, leading to the formation of the blastocyst. Blastocyst Structure: Trophoblast (outer layer of cells): Develops into the placenta and embryonic membranes, which provide support and nutrition during pregnancy. Inner Cell Mass (ICM): A cluster of cells that will eventually develop into the embryo itself. Blastocoele (fluid-filled cavity): Allows for further cell division and blastocyst expansion. Hatching and Implantation Process: As the blastocyst expands, it breaks out of its protective outer shell (zona pellucida), typically on day six post-fertilization. Within 24 hours after hatching, the blastocyst implants into the uterine lining, usually attaching to the anterior or posterior upper wall of the uterus. Implantation occurs in three phases: Movement to an optimal position in the uterus. Adhesion to the uterine lining. Invasion of the uterine lining, allowing the blastocyst to access essential nutrients for further development. Is the term "Conceptus" the same as "Blastocyst"? Not exactly. Conceptus is a broader term referring to all structures of early pregnancy, including the blastocyst, its supporting membranes, and the developing placenta. In contrast, blastocyst refers specifically to the embryonic stage between days five and six post-fertilization, before implantation occurs.
A term referring to the cells formed during the early mitotic divisions of the zygote—the first cell created after the sperm fertilizes the egg. The blastomere stage occurs on the first day post-fertilization and represents the initial phase of embryonic development. As cell divisions continue, blastomeres organize into a morula (a dense cluster of cells), which then develops into a blastocyst—the stage at which implantation in the uterus begins.
A biological process that sperm cells must undergo to gain the ability to fertilize an egg. During capacitation, the sperm undergoes biochemical and physiological changes within the female reproductive tract, enabling it to penetrate the egg's outer shell and fertilize it. This process includes: Increased sperm motility Alterations in the sperm cell membrane, preparing it for the acrosome reaction—a critical step that allows the sperm to break through the egg’s protective layer and achieve fertilization.
A form of infertility caused by structural or hormonal abnormalities in the cervix, which obstruct sperm from passing into the female reproductive system. Possible Causes: Structural abnormalities in the cervix – May result from prior surgeries such as LEEP (removal of abnormal cervical cells) or cone biopsy, which can lead to scarring or cervical stenosis (narrowing of the cervical canal), making it difficult for sperm to pass through. Cervical mucus abnormalities – In some cases, cervical mucus may be too thick, preventing sperm from traveling through the cervix to the uterus and fallopian tubes. Medical Solutions: Most cases of cervical factor infertility can be addressed with intrauterine insemination (IUI), in which sperm is placed directly into the uterus, bypassing the cervix.
A natural secretion produced by the cervix that varies in quantity and consistency throughout the menstrual cycle based on hormonal fluctuations. Characteristics of Cervical Mucus During the Cycle: Before Ovulation: Becomes thin, clear, and stretchy, facilitating sperm movement toward the fallopian tubes and increasing fertilization chances. After Ovulation: Under the influence of progesterone, it thickens and becomes sticky, forming a barrier that prevents sperm and bacteria from entering the uterus. Role in Fertility: The quality of cervical mucus serves as an indicator of hormonal balance. Issues such as overly thick or acidic mucus may hinder sperm survival and motility, contributing to infertility.
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