We will not address this difficult concept in this study session, but focus instead on the theoretical knowledge of how fertilisation and implantation of the ovum in the uterus occurs, and how the fetus is nourished as it develops during the nine months of gestation. This study session will also help you to recognise factors affecting fetal development that may lead to complications during the antenatal period. SAQs 5.
Pregnancy happens when an egg is fertilized by sperm in the fallopian tubes. Once fertilized, the cells start to multiply and grow. In the uterus, the morula becomes a blastocyst and eventually burrows into the uterine lining in a process called implantation.
During fertilization, the sperm and egg unite in one of the fallopian tubes to form a zygote. Then the zygote travels down the fallopian tube, where it becomes a morula. Once it reaches the uterus, the morula becomes a blastocyst.
To become pregnantthe following steps must occur:. Following ejaculation, the semen forms a gel that protects it from the acidic environment of the vagina. The gel is liquefied within 20 to 30 minutes by enzymes from the prostate gland.
Sperm bring more than DNA to the party. They also pick up RNA on their way through the epididymis, a duct situated between the testis and the vas deferens. This RNA, it turns out, influences gene regulation in developing embryos, helping them implant in the uterus more efficiently.
Use the link below to share a full-text version of this article with your friends and colleagues. Learn more. It was concluded that melatonin administration to sperm donors improved freezability of ram semen collected from these rams and reduced enzyme leakage through sperm cells during cryopreservation.
In humans, implantation is the stage of pregnancy at which the embryo adheres to the wall of the uterus. At this stage of prenatal developmentthe conceptus is called a blastocyst. It is by this adhesion that the embryo receives oxygen and nutrients from the mother to be able to grow.
Implantation is when a fertilized egg, or blastocyst, has attached to the lining of the uterine wall. It marks the beginning of pregnancy. The medical community, including the FDA, the American College of Obstetricians and Gynecologists, and the National Institutes of Health are in agreement that a woman is not considered to be pregnant until implantation has occurred.