Egg meets sperm (article) | Embryology | Khan Academy
To become pregnant, sperm (from a male) has to meet an egg (from a female). This can happen when a male and female have sexual intercourse, when the. Sperm Meets Egg: Weeks 1 to 3 of Pregnancy. Something RELOAD YOUR SCREEN OR TRY SELECTING A DIFFERENT VIDEO. Something. Fertilization: Sperm meets egg. The mature egg is fertilized when it is joined with a sperm cell. This usually happens after a penis* has ejaculated semen inside.
This is called ovulation. After the egg is released, it moves into the fallopian tube where it stays for about 24 hours. If the egg is not fertilized during that time, the egg disintegrates breaks down and menstruation your period begins 2 weeks later.
Sperm meets egg The mature egg is fertilized when it is joined with a sperm cell. Sperm is contained in the semen which travels up the vagina, through the cervix and uterus and into the fallopian tubes.
If an egg is less than 24 hours old, it can be fertilized by a sperm.
Fertilization sometimes but rarely happens when semen has been ejaculated outside but near the entrance of the vagina. The fertilized egg attaches to the lining of the uterus and pregnancy begins.
Most eggs are fertilized by sperm while still in the fallopian tube. The fertilized egg then travels down the fallopian tube into the uterus. 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.
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. The vagina and uterus are very susceptible to infection, so the body has to balance on a fine line between protecting these areas and allowing sperm to come through.
Diagram showing the female reproductive tract. The path of the sperm is highlighted via a blue arrow. As the sperm approach the egg, they bind to the zona pellucida in a process known as sperm binding. This triggers the acrosome reaction, in which the enzymes of the acrosome are freed.
Conception - Family Planning
When the sperm cell finally reaches the egg cell, the plasma membranes of the two cells fuse together and the sperm releases its genetic material into the egg. Fusion also triggers the cortical reaction. When the sperm and egg fuse it triggers a release of calcium ions, which cause the cortical granules inside the egg to fuse with the plasma membrane.
As they fuse, these granules release their contents outside of the cell, toward the remains of the zona pellucida. The enzymes of the cortical granules further digest the zona pellucida, making it unable to bind more sperm, while other molecules found in the granules create a new protective layer around the fertilized egg.
By creating a new barrier and destroying the initial interface between sperm and egg, the cortical reaction prevents polyspermy, or the fertilization of a single egg by multiple sperm.Egg And Sperm Meet Main Symptoms That You Should Noticed
Other sperm reaching the egg now are just shunted away. A diagram showing the steps sperm take to fertilize the egg. Copper intrauterine devices, or IUDs take advantage of sperm cell properties to prevent fertilization.