The cardiovascular system starts to pulse making it the earliest organ system to function. During the 5th week, the arms and legs are beginning to form. The embryo will have all basic organs and parts except sex organs, by the 8th week. At this point the fetal stage begins. The cell differentiation is all most complete by this stage and the embryo is now a fetus.
The cells travels to the lining of the uterus and the developing cells is then called an embryo. Once the embryo is attached to the uterus wall, the woman’s menstrual period has stopped. After eight weeks the embryo will have grown to around 3-4cm, will have a recognisable heartbeat and the eyes, ears, mouth, legs and arms will have started to develop. At this stage the embryo is now called the foetus. During the remaining seven months before birth all organs will continue to develop.
This stage contains sex chromosomes “ organized structure from the DNA” in here the sex of the baby is determine but it can’t be show yet because is not big enough. The baby is about ¼ inch long. After the zygote stage is done the next stage would be the embryo. The second stage is the embryo here is where the body starts to form. The embryo begins with the formation of the nervous system.
These cells then travel to the lining of the uterus where it then becomes embedded. The collection of cells that are now developing which is now called an embryo that attaches to the cell wall which is called the placenta this then produces a chemical signal which means that the women will not have another menstrual period. Eight weeks after conception the embryo will have grown up to 3 to 4cm it will also have a heartbeat that is recognisable and have features starting to grow this is called a foetus. In the next seven months the organs will continue to grow
Human life begins with conception. A fertile woman produces an egg cell each month two weeks after the last menstrual period. The egg cell travels from the ovary along the fallopian tube towards the uterus. If sexual intercourse takes place while the egg is in the fallopian tube, there is a possibility of conception. Fertilisation is when the genetic material in the sperm joins with the genetic material in the ovum to start a new life.
The egg and sperm are known as gametes and each has 23 chromosomes which code all the child’s genetic material. One of the 23 is the sex chromosome (either X or Y). The ova contains only an X chromosome whereas the sperm carry either an X or a Y. When a Y sperm fertilises an egg, the embryo will have and XY pair of chromosome and will be a boy; when an X sperm fertilises an egg, the result is a female embryo with an XX pair of chromosomes. Hence it is always the male who determines the sex of the child.
Birth: Around 38 weeks after the fertilisation has happened, the foetus will have developed enough for it to survive outside its mothers body. In most of the cases the babies are born with their head coming out first, but sometimes there are cases where the babies are born with their bottom coming out first and this what call the – breach birth. If there is a problem with a natural delivery then caesarean section is performed. Birth is the end of the foetal stage and the beginning of the infancy. Labour, or the process of birth is divided into three stages, which are: Dilation Delivery of the body Delivery of the placenta Dilation: this is where the strong uterine contractions cause the cervix to dilate until it is wide enough for the mother to bead to pass through- usually about 10 cm.
After the egg has been fertilised by one single sperm, no more sperm can enter and the egg becomes a Zygote. The Zygote travels through the fallopian tubes in to the womb where it attaches itself to the lining of the womb and begins to grow. This is at about 6-10 days after the woman’s egg is released. (nhs.uk) accessed 18.11.2013 Between 6-10 days and 8 weeks, the Zygote is called an Embryo, The sac that forms around the baby (amniotic) is filled with fluid which protects the baby like a cushion incase mum has ay falls or bumps. The placenta starts growing, this is full of blood vessels that take food and oxygen to the baby and takes away any waste produce throught the umbilical cord.
Gamete production is the responsibility of the ovaries, whereas protection and nourishment of the growing embryo and fetus before birth are functions of the uterus. The two uterine tubes, one from each ovary, provide pathways for the female gametes (eggs) to get from the ovaries to the uterus. The portion of the reproductive tract called the vagina is between the narrow uterine cervix and the outside of the body. In female humans there is a second opening where the urethra from the urinary bladder connects to the outside of the body. The urethral opening is normally separate from, and in front of, the vagina.
When the eggs are fertilized by sperm, conception occurs. When conception does not occur, a female menstruates, which means she sheds a layer of her uterine liner. The female reproductive system is also responsible for producing the female sex hormones that maintain and allow the reproduction cycle to function smoothly. The reproductive system consists of the following major organs: the vagina, cervix, uterus, fallopian tubes, and ovaries which are located within the pelvic cavity. The female reproductive system produces female sex hormones which deal with maintaining a stable internal environment or homeostasis.