Relationship between gamete zygote fertilization calendar

Zygote Intrafallopian Transfer (ZIFT)

relationship between gamete zygote fertilization calendar

zygote A fertilized female gamete: the product of the fusion of the nucleus of the .. day of the woman's last menstrual period and each trimester is three calendar . Embryo: An egg that has been fertilized by a sperm and undergone one or During the process of zygote intrafallopian transfer (ZIFT), the. A zygote is the union of the sperm cell and the egg cell. Also known as a fertilized ovum, the zygote begins as a single cell but divides rapidly in.

This begins the process of forming the fetus and eventually the baby. The first division produces two identical cells, the second produces four cells, the third produces eight cells, etc. After many cell divisions, the cells begin to specialize and differentiate form particular tissues and organs.

Fertilization usually occurs in the fallopian tubeand the first few cell divisions occur as the developing embryo moves to the uterus. The first division occurs about 30 hours after fertilization. As the zygote divides, some of the cells formed will develop into the placenta. Approximately six days after fertilization, the ball of cells attaches to the uterine wall.

Sex determination Men and women each have 22 pairs of non-sex chromosomes and two sex chromosomes. Men's sex chromosomes are X and Y.

What is the relationship between gamete ,zygote and fertilization?

A mature sperm cell that has undergone the chromosome division process from 46 to 23 chromosomes produces a cell that is either X or Y. Women's sex chromosomes are X and X. The eggs that women produce have only X chromosomes. Therefore, the sperm determines whether the zygote is XY or XX, which is the initial step on the biological path to becoming a male or female. Developmental periods The term embryo refers to the developing baby between the second week after conception and the eighth week after conception.

Doctors use the term fetus from the ninth week after conception to birth. A pregnancy is broken down into three trimesters. The first trimester begins with the first day of the woman's last menstrual period and each trimester is three calendar months. Twins Twins may arise in two ways.

Identical twins are called "monozygotic" because both individuals are formed from the same zygote.

relationship between gamete zygote fertilization calendar

As the zygote divides to form the baby, two separate individuals form instead of one. Fraternal twins are called "dizygotic" because each individual develops from a different zygote.

Two eggs are ovulated, and a separate sperm fertilizes each egg. Therefore, identical twins have exactly the same DNA in each cell and fraternal twins share the same amount of DNA as brothers and sisters.

relationship between gamete zygote fertilization calendar

Sometimes it is impossible to tell monozygotic twins from dizygotic twins based on the placenta and the fetal membranes. If a person wants to determine whether twins are monozygotic or dizygotic, DNA studies of blood cells will provide a definitive answer. Abnormalities The zygote normally contains two complete sets of 23 chromosomes, and two copies of every gene.

If the egg or sperm that fuse to form the zygote is abnormal, the zygote will also be abnormal. For example, Down syndrome is caused by an extra chromosome number 21 from the egg or sperm cell. Since the cells formed by division of the zygote are identical to the zygote, any abnormality in the zygote will be in every cell of the baby. Abnormalities can also arise when the zygote begins to divide. This type of abnormality is usually severe, eventually leading to a miscarriage. If an abnormality occurs after the zygote has divided one or more times, the baby will have some normal cells and some abnormal cells.

This situation is referred to as "mosaicism" and "mosaic" may be used to describe the person's condition. Molar pregnancies Molar pregnancies can occur in one of two ways. Sometimes the original cell that duplicates and divides to form the fetus is completely of paternal origin.

Implantation (human embryo) - Wikipedia

The chromosomes in a sperm duplicate themselves, then proceed to divide as if they were a normal zygote. These pregnancies are completely abnormal and miscarry.

Another type of molar pregnancy occurs when two sperm fertilize one egg. The zygote is triploidy and has 69 chromosomes instead of These changes reach their maximum about 7 days after ovulation. Furthermore, the surface of the endometrium produces a kind of rounded cells, which cover the whole area toward the uterine cavity.

relationship between gamete zygote fertilization calendar

This happens about 9 to 10 days after ovulation. The uterine glands, on the other hand, decrease in activity and degenerate around 8 to 9 days [6] after ovulation in absence of pregnancy.

The decidual cells originate from the stromal cells that are always present in the endometrium. However, the decidual cells make up a new layer, the decidua. The rest of the endometrium, in addition, expresses differences between the luminal and the basal sides. The luminal cells form the zona compacta of the endometrium, in contrast to the basalolateral zona spongiosawhich consists of the rather spongy stromal cells.

Fertilization, Implantation and gtfd.info4

This is an expansion of it, further developing the uterine glands, the zona compacta and the epithelium of decidual cells lining it. The decidual cells become filled with lipids and glycogen and take the polyhedral shape characteristic for decidual cells. Trigger[ edit ] It is likely that the blastocyst itself makes the main contribution to this additional growing and sustaining of the decidua. An indication of this is that decidualization occurs at a higher degree in conception cycles than in nonconception cycles.

Zygote Intrafallopian Transfer: ZIFT

Decidua basalis - This is the part of the decidua which is located basalolateral to the embryo after implantation. Decidua capsularis - Decidua capsularis grows over the embryo on the luminal side, enclosing it into the endometrium.

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  • Implantation (human embryo)

It surrounds the embryo together with decidua basalis. Decidua parietalis - All other decidua on the uterine surface belongs to decidua parietalis.

Decidua throughout pregnancy[ edit ] After implantation the decidua remains, at least through the first trimester.

Its function as a surrounding tissue is replaced by the definitive placenta.

relationship between gamete zygote fertilization calendar

However, some elements of the decidualization remain throughout pregnancy.