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Fertilization was not understood in antiquity. Hippocrates believed that the embryo was the product of male semen and a female factor. Aristotle held that only male semen gave rise to an embryo, while the female only provided a place for the embryo to develop, [5] a concept he acquired from the preformationist Pythagoras.
In biological terms, the development of the human body entails growth from a one-celled zygote to an adult human being. Fertilization occurs when the sperm cell successfully enters and fuses with an egg cell (ovum). The genetic material of the sperm and egg then combine to form the single cell zygote and the germinal stage of development commences.
The exact cause of morning sickness remains unknown. Nausea and vomiting in pregnancy is typically mild and self-limited, resolving on its own by the 14th week of pregnancy. Other causes should also be ruled out when considering treatment. Initial treatment is typically conservative, and may include changes to diet and emotional support.
The term "conception" refers variably to either fertilization or to formation of the conceptus after its implantation in the uterus, and this terminology is controversial. The zygote will develop into a male if the egg is fertilized by a sperm that carries a Y chromosome , or a female if the sperm carries an X chromosome . [ 5 ]
Pregnancy is the period of time during which the fetus develops, dividing via mitosis inside the uterus. During this time, the fetus receives all of its nutrition and oxygenated blood from the mother, filtered through the placenta , which is attached to the fetus' abdomen via an umbilical cord .
In unexplained infertility abnormalities are likely to be present but not detected by current methods. Possible problems could be that the egg is not released at the optimum time for fertilization, that it may not enter the fallopian tube, sperm may not be able to reach the egg, fertilization may fail to occur, transport of the zygote may be disturbed, or implantation fails.
A pregnancy test detects the presence of the pregnancy hormone human chorionic gonadotropin in a person’s body. The body doesn’t produce that hormone until several days after conception.
The zygote, which will divide multiple times as it progresses throughout embryonic development, is one part of a seed. Other seed components include the endosperm , which is tissue rich in nutrients that will help support the growing plant embryo, and the seed coat, which is a protective outer covering.