How Pregnancy Happens - Teen Health Source
Egg Fertilization by the Sperm. Updated on October 9, Q: How does the egg meet the sperm? Sperm is deposited in the vagina and moves up through the. Conception is the moment when egg and sperm meet. It can take These are the two hormones that would help maintain a pregnancy. When the levels of these. How does pregnancy happen? Fertilization: Sperm meets egg In other words , sperm that was ejaculated on Monday could fertilize an egg released on.
The fertilized egg then travels down the fallopian tube into the uterus.
Egg meets sperm (article) | Embryology | Khan Academy
This can take days. When the egg reaches the uterus, it may attach itself to the uterine lining the endometrium and pregnancy will begin. Many fertilized eggs are never implanted and are flushed out of the body with the next period. How do I know when ovulation happens?
The best way to tell when ovulation takes place is to use a fertility awareness method FAM. If you are not using FAM, it can be hard to tell when you ovulate.
How Pregnancy Happens
To learn more about FAM, check out our info page [ Link ]. Useful Tip Even though an egg can only be fertilized within 24 hours of being released, sperm can live inside the body for up to five days.
In other words, sperm that was ejaculated on Monday could fertilize an egg released on Friday. The zona pellucida helps protect the egg and is responsible for mediating the initial meeting of sperm and egg.
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- Human fertilization
Cortical granules filled with enzymes line the inside of the cell membrane, and will help make sure that only one sperm can fertilize the egg.
The setting Egg and sperm travel in opposite directions to meet in most often the fallopian tubes.
During ovulation, ovaries release an egg into one of the fallopian tubes, and the egg proceeds down the tube toward the uterus, which is being prepared for possible implantation. Part of this preparation involves elevated levels of estrogen and luteinizing hormone LH. LH triggers the ovaries to release the egg, while higher blood estrogen levels stimulate the vaginal membrane to secrete glycogen, which is then metabolized to lactate. This lowers vaginal pH to as low as 3.
However, this environment can also be toxic to sperm, though the semen a basic fluid can buffer the vaginal acidity to preserve sperm cells. Only about 1 in 1 million sperm that are ejaculated into the vagina will reach the site of fertilization. Estrogen also relaxes the cervix, causes cervical mucus to become watery and more alkaline, and stimulates uterine contractions — all of which help sperm penetrate and navigate the female reproductive system. Relaxing the cervix allows sperm to pass from the vagina into the uterus and reduces a potential physical barrier.
Cervical mucus may prevent sperm from passing into the uterus, but during ovulation when the egg is released from the ovaries, the mucus gets thinner and lower in pH.
These changes make the mucus a great transport medium for the sperm, and help the sperm continue traveling. As we can see, the progress of sperm is really influenced by where in the menstrual cycle the female is.
The closer to ovulation, the easier it is for sperm to pass. Male Fertility After traveling through the vaginal canal, the strongest sperm make it to the cervix. From here, the sperm must travel through the uterus and into one of the fallopian tubes.
Since the human body functions to procreate, the egg that is released monthly from the ovaries waits for sperm cells in the fallopian tube for about a day. Additionally, sperm can survive in the female reproductive track for up to 5 days. This union of egg and sperm creates a zygote fertilized egg and this new zygote cell has a core of 46 chromosomes 23 from the sperm and 23 from the egg.
Embryonic Development This new zygote cell begins to divide rapidly over the next few hours through a process called mitosis, and this expanded bundle of cells is now called an embryo. If the fertilizing sperm has a Y chromosome, the embryo will develop into a male baby, while a fertilizing sperm with an X chromosome will develop into a female baby.
Implantation By the time the fertilized egg reaches the uterus, it is a cluster of about cells, and it forms a blastocyst. Simultaneously, the lining of the uterus gets thicker, and the cervix is closed off with a mucus plug that will stay in place until the end of the pregnancy term.
Around the time of implantation, some females may notice spotting light bleedingwhich should only last about 48 hours. This irregularity is called an ectopic pregnancy and it can be very dangerous. In these cases, the female will either need to take medication to stop the embryo from growing, or have surgery to prevent the fallopian tube from rupturing. Detection Naturally, about half of all fertilized eggs are lost before a female even knows that she is pregnant.
This loss could be due to many reasons, including the blastocyst implanting but not growing, or the blastocyst growing but ceasing development.