Oosperm refers to the meeting of sperm and eggs.This process is the process of fertilization.The fertilization process takes about 24 hours.When an ablespermEnter aSecondary oocyteOfTransparent bandThe fertilization process begins when.When the chromosomes of egg pronucleus and sperm pronucleus are fused together, the fertilization process is completed.
Taking people as an example,spermAndeggstayFallopian tubeWhen they meet, they form a fertilized egg, and life begins.After fertilization, the egg divides into two cells, which divide about every 12 hours.This mass of cells enters from the fallopian tubeuterusIt secretes liquid and expands into aHollow ball, calledblastocyst。The hollow ball will become two layers in a few days. The ball contains a small amount of liquid, and the cell clusters are piled on the side of the ball.The ball wall will become the placenta and amnion, and the cells inside will becomefetus。The fertilized egg comes to the uterus by the contraction of the fallopian tubecilia, constantly pushing the liquid in the tube, which also plays an auxiliary role in transporting the fertilized eggs.Generally, the fertilized egg reaches the uterine cavity about 4 days after ovulation, about the 9th day after the egg leaves the egg,embryodrillingendometrium, grow up.
Chinese name
Zygote
Foreign name
zygote[2]
Fission time
Split about every 12 hours
Composition
Sperm and egg
Category
Mammalian fertilized eggs with human as an example
30 hours after fertilization, the fertilized egg moves towards the uterus.It reached the uterus after 3-4 days.At the same time, the fertilized egg begins to undergo repeated cleavage, forming multiple daughter cells (also known as mitospheres).On the third day after fertilization, the fertilized egg develops into a solid cell mass containing 16 cells, which is called a morula.On the 4th day after fertilization, when the morula increases to 100 cells, it enters the uterine cavity, and then a cavity filled with liquid appears in the morula, that is, the blastocyst cavity. The morula develops into a blastocyst (also called blastocyst).Around the blastocyst is a trophoblast composed of a single layer of cells, and the rest of the cells gather to form an inner cell mass protruding into the fluid cavity, which is an early blastocyst.After entering the uterus, the blastocyst wanders in the uterus for 2-3 days or more, that is, 6-7 days after fertilization, and develops into a late embryo sac[1]。
Fertilization process
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Sperm egg meetingIs to form a fertilized egg.This process is the process of fertilization.
Fertilization process requires about24 hours。When an empowered sperm enters the zona pellucida of a secondary oocyte, the fertilization process begins.When the chromosomes of egg pronucleus and sperm pronucleus are fused together, the fertilization process is completed.
During cleavage and blastocyst formation, the cells of the fertilized egg undergo metabolic changes,Trophoblast cellThe inner surface of the adnexa is covered by the processes on the adjacent cells.Because the cell surface can transmit the environment to affect the embryo, the changes in the cell surface can be explained by nutrient intake, differentiation, preparation for implantation or mitosis.
Development and implantation of fertilized eggs
After fertilization, the egg begins mitosis and moves towards the uterine cavity while splitting.The fertilized egg divides into 2 cells after 36 hours in the oviduct, and into 16 cells after 72 hours, called morula.On the 4th day after fertilization, the cell mass enters the uterine cavity and continues to develop in the uterine cavity. At this time, the cells have divided into 48 cells, which become blastocysts ready for implantation.The blastocyst can secrete a hormone to help it bury itself into the endometrium.From the 6th to the 7th day after fertilization, the blastocyst begins to implant.The implantation position is mostly in the upper 1/3 of the uterus. The completion of implantation means that the embryo has been placed, and the placenta has begun to form, and the fetus has been pregnant.
Sexual intercourseLater, men's ejaculated semen contained more than 1-3 billion sperm, and this huge "team" rushed upstream in the female reproductive tract.The sperm sways by its tail and swims at a speed of 2-3 mm per minute. After a long "journey" - vagina, cervix and uterine cavity, it reaches the fallopian tube, where the sperm and egg (actually the secondary oocyte in the middle of the second meiotic division) "meet".In the above process, great changes have taken place in the number, morphology, structure, biochemical reaction and other aspects of sperm, and finally only dozens to 200 sperm can reach the end point.
First, the radial crown cells around the egg are dispersed under the action of enzymes in the oviduct mucosa and semen, and several sperm move through the radial crown by tail.Sperm acrosome releases hyaluronidase and gliase, digests the zona pellucida around the egg, and penetrates the zona pellucida.The sperm cell membrane is fused to the egg cell membrane, and this egg is called the fertilized egg.Although hundreds of sperm can penetrate the zona pellucida, usually only one sperm can enter the egg cell and combine with it to form a fertilized egg. This biological reaction that prevents multiple sperm from entering the egg cell is called zona pellucida reaction.
After the sperm enters the egg cell, the tail disappears, the head becomes round and swollen, forming a male pronucleus;After the second meiotic division of the secondary oocyte, the nucleus of the secondary oocyte forms a female pronucleus.The male pronucleus contacts the female pronucleus, and their respective nuclear membranes disappear and unite. The bisexual chromosomes mix and pair in the subsequent zygotic division. Pregnancy ends and a new life begins.The fertilization process takes about 24 hours.
Prerequisites
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Pregnancy is a complex physiological process, which must meet the following conditions:
1. The ovary discharges normal eggs.
2. The semen is normal and contains normal sperm.
sperm
3. The egg and sperm can meet in the fallopian tube and combine to become a fertilized egg.
4. The fertilized eggs are successfully transported into the uterine cavity.
5. The endometrium has fully prepared a bed suitable for fertilized eggs.
Any abnormality in these links can hinder pregnancy.
Implantation process
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Implantation began about 6-8 days after fertilization and was completed 11-12 days later.Generally, the implantation is slightly more in the posterior wall than in the anterior wall, and more in the midline than in the lateral wall.
oneAttach:With the local perforation or complete disappearance of the zona pellucida, the trophoblast near the end of the inner cell group rapidly divides and is close to the endometrial epithelium.The tiny villi of two relative tissue planes cross the gap and cross each other widely in finger shape, and then the villi cross each other.
Implantation of fertilized eggs
twoImplantation:The blastocyst (also called blastocyst) attaches to the endometriumepithelial cellsThe cell membrane gradually disappeared and became a multinucleated cell body.The trophoblast also differentiates into two layers, and the inner layer retains the cell membrane, which is called cytotrophoblast;The outer cell membrane disappears, which is called syncytiotrophoblast.The syncytiotrophoblast has a strong erosive force, eroding the uterine detachment, forming a small gap, and slowly sinking the blastocyst into the dense layer of endometrium.About the 10th day after fertilization, the whole blastocyst is located in the endometrium. On the 11th day, there is a blocking plug composed of small blood clots and cell fragments in the endometrium. On the 12th day, the blastocyst is almost completely covered by proliferative epithelium, forming a small bulge, and the implantation is completed.
Implantation mechanism
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One end of the fertilized egg clings to the endometrium and immediately secretes an enzyme that breaks down proteins, dissolves the endometrium and forms a gap about 1mm in diameter.The blastocyst is embedded into the endometrium from the gap. The epithelial gap is quickly repaired, and the settlement of the blastocyst is completed.This process is called implantation or implantation of fertilized eggs in medicine.
1. The zona pellucida must fall off and dissolve before the blastocyst is released and attached to the endometrium.The substances that can make the zona pellucida fall off and dissolve include: ① enzymes secreted by blastocysts before implantation, such as △ - 3β-HSD and 17β-HSD；②There was a kind of myoglobin antigen similar to rabbit embryo kinin in the endometrium and uterine fluid.
Graphic development process
2. Estrogen before ovulation makes endometrial epithelium proliferate, while low levels of estrogen and progesterone after ovulation can make glandular epithelium proliferate.Progesterone in luteal phase plus a small amount of estrogen secreted by corpus luteum can cause secretion of glandular epithelium and proliferation of interstitial cells, which become decidual like changes.
Progesterone can make the endometrium of the two uterine horns produce embryonic kinin, which promotes the growth and development of the blastocyst, produces villi, and makes the villi contain bicarbonate ions (HCO3), which is associated with thecarbonic anhydraseThe combination of the two can make the part highly alkaline, cause the disintegration of the local intima tissue, and finally make the pregnant egg implant.
The chorionic gonadotropin (HCG) is secreted by the blastocyst before implantation. On the 10th day of fertilization, the concentration of HCG in the implantation site can be as high as 10000 IU/L.HCG can change ovarian corpus luteum into pregnant corpus luteum, and hormones secreted by pregnant corpus luteum can change endometrium into decidua, creating conditions for implantation and development of pregnant eggs.Good pregnancy is a new concept of fertility: three months or even six months before the sperm and egg combine, the preparation for pregnancy begins.
development
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Fertilization occurs after the formation of corpus luteum, and progesterone secreted by corpus luteum promotesFallopian tubeepithelial cellsSecreting nutrient fluid to nourish and run the fertilized egg.24-36 hours after fertilization, the fertilized egg divides into two cells and continues to divide, dividing and running.72h after fertilization, it divides into a solid mass of 12-16 cells, called morula.
Because of the contraction of oviduct smooth muscle and the oscillation of mucosal epithelium cilia, the fertilized egg crosses the ampulla isthmus junction.Through the isthmus, morula forms and enters the uterus.The fertilized egg has cleavage in the oviduct, but its volume does not increase.
The morula absorbs nutrition from the uterine cavity, and the uterine cavity fluid infiltrates into the morula. The cell divides and proliferates, and develops into a blastocyst about 96 hours after fertilization.The composition of the blastocyst: ① the trophoblast is composed of peripheral cells; ②The space surrounded by trophoblast contains liquid, which is called blastocyst cavity; ③The cell group at one end of the blastocyst cavity is called the inner cell group, which later develops into an embryo.The morula entered the uterine cavity in a free state for about 3-4 days.
Hormone reference value
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Follicle stimulating hormone(FSH): It is a glycoprotein hormone secreted by basophils in the anterior pituitary, and its main function is to promote the development and maturation of ovarian follicles.The concentration of blood FSH is 1.5-10mIU/ml in the pre ovulation period, 8-20mIU/ml in the ovulation period, 2-10mIU/ml in the post ovulation period, and generally 5-40mIU/ml is taken as the normal value.The low FSH value can be seen during the treatment of estrogen and progesterone, Sheehan's syndrome, etc.FSH is high inPremature ovarian failure, ovarian insensitivity syndrome, primary amenorrhea, etc.If FSH is higher than 40mIU/ml, it is invalid for ovulation promoting drugs such as clomiphene.
Luteinizing hormone(LH): It is also a glycoprotein hormone secreted by basophils in the anterior lobe of the pituitary gland, mainly to promote ovulation. Under the synergistic effect of FSH, it forms the corpus luteum and secretes progesterone. The concentration of blood LH is 2-15mIU/ml in the pre ovulation period, 30-100mIU/ml in the ovulation period, 4-10mIU/ml in the late ovulation period, and the normal value is 5-25mIU/ml in the non ovulation period,If it is lower than 5mIU/ml, it indicates that gonadotropin function is insufficient, which is seen in Sheehan's syndrome. If high FSH is added to high LH, ovarian failure has been confirmed, and no other examination is necessary.LH/FSH ≥ 3 is one of the bases for the diagnosis of polycystic ovary syndrome.
Prolactin(PRL): lactation by one of the eosinophils in the anterior pituitaryTrophoblastSecretion is a simple protein hormone, whose main function is to promote the proliferation of mammary glands, the production of milk and milk excretion.In non lactation period, the normal value of blood PRL is 0.08-0.92nmol/L.If it is higher than 1.0 nmol/L, it means hyperprolactinemia. Excessive prolactin can inhibit the secretion of FSH and LH, inhibit ovarian function and ovulation.
Estradiol(E2): It is secreted by the ovarian follicle, and its main function is to promote the transformation of endometrium into the proliferative phase and promote the development of female secondary sexual characteristics.The blood E2 concentration is 48-521 pmol/L in the pre ovulation period, 70-1835 pmol/L in the ovulation period, and 272-793 pmol/L in the post ovulation period. The low value is found in low ovarian function, premature ovarian failure, and Sheehan's syndrome.
progesterone(P) It is secreted by the corpus luteum of the ovary, and its main function is to promote the transformation of the endometrium from the proliferative phase to the secretory phase.The blood P concentration was 0-4.8 nmol/L before ovulation and 7.6-97.6 nmol/L during late ovulation. The low blood P value during late ovulation was found in luteal insufficiency, ovulatory dysfunctional uterine bleeding, etc.
testosterone(T) : Testosterone in women, 50% from the peripheralAndrostenedioneIn turn, about 25% of the adrenal cortex secretion comes from the ovary.Its main function is to promote the development of clitoris, labia and pubic mound.It has an antagonistic effect on estrogen and has a certain impact on systemic metabolism.The normal concentration of blood T in women is 0.7-3.1nmol/L, and the blood T value is high, called high testosterone, which can cause infertility. When suffering from polycystic ovary syndrome, the blood T value also increases.Other hormones shall be measured when necessary according to clinical manifestations.
Best opportunity
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1. Let the newly discharged eggs be fertilized immediately, which can avoid the external environment, and has the greatest chance of breeding children with good physique and high IQ.
2. The best childbearing age for Chinese women is 24-34 years old. The father is 30-40 years old and the mother is 24-29 years old.
3. The temperature in late summer and early autumn is suitable, avoiding the time of virus epidemic and disease outbreak.Rich food can make pregnant women get the most adequate nutrition and store it in the body, so as to prevent the nutritional loss caused by vomiting reaction in early pregnancy, which is beneficial to the early brain development of the fetus.It is spring in the middle and late pregnancy, and the pleasant environment is very conducive to prenatal education.
4. When you are pregnant, you should avoid these changes in the natural environment: solar magnetic storms, earthquakes, eclipses of the sun and the moon, and full moon nights will cause great changes in people's mood, and the quality of sperm and egg cells will decline.Thunder and lightning produce strong X-ray, which will cause chromosome aberration of germ cell.Solar flares will occur around sunspots, which will damage germ cells and embryos, resulting in mental retardation of infants after birth[1]。
Is the bleeding normal
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During the whole process of implantation, some people will bleed, but the color of the blood is mostly light pink, just like when menstruation just came. If it is dark red or there is a lot of flow, it should be considered that it is a premonitory miscarriage, and you should seek medical advice in time.
Artificial insemination
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In fact, artificial insemination is commonly referred to as artificial insemination, which is a method of artificially injecting male semen into the cervix or uterine cavity of women to assist in pregnancy.
Conditions for artificial pregnancy
Pregnancy is a very complicated process, as is artificial pregnancy. Not all infertile patients can accept artificial pregnancy, but they also need to meet the following conditions:
1、 Women should discharge healthy and mature eggs
The ovaries of normal women will contain hundreds of thousands of primordial follicles, but only about 400-500 mature follicles.When women's ovaries mature, there will be interaction between ovaries during ovulation every month, and women will only ovulate one egg.Of course, there will also be two eggs discharged from one ovary at the same time.
2、 You need normal sperm
Sperm is a necessary condition for pregnancy. Even for artificial pregnancy, men must have healthy sperm.When the male reproductive organs mature, the testes will not only produce male hormones, but also produce healthy sperm. Only with the combination of sperm and eggs can women successfully conceive.
Implantation symptoms
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The symptoms of fertilized egg implantation are also different according to individual conditions.Some people begin to have unpleasant symptoms in the first few weeks after conception.But some people have no early symptoms at all.Generally, the symptoms of fertilized egg implantation are nausea, nausea or loss of appetite. The likes and dislikes of food will also change, and the secretion of saliva will also increase.The specific types are as follows:
1. Menstruation is the earliest and most important "signal" of early pregnancy.Married women of childbearing age with normal menstrual cycle should consider the possibility of pregnancy if their menstruation is overdue for more than 10 days. If their menopause is over 2 weeks, they need to go to the hospital for examination.
2. Change of appetite. Some women begin to change their appetite soon after menstruation expires (1-2 weeks).I don't like the food I usually like.Generally, after half a month to one month, these symptoms will naturally disappear.
3. Nausea and vomiting usually occur in the morning or on an empty stomach.Some pregnant women especially like acidic and raw cold food.It's called "picky eating".4. Breasts become softer. If your breasts feel tingling, soft and swollen, you may be pregnant.This symptom may appear in the first few days after conception.After your body adapts to a large number of hormones, the pain will subside.
5. The symptoms of bleeding or spasm may be accompanied by slight pink or brown stains eight days after ovulation and implantation.There may also be some punctate bleeding during the physiological period, but this is not the real physiological period.This is the result of the implantation of the fertilized egg in the endometrium.
6. Tiredness. After pregnancy, dizziness, fatigue, drowsiness and other phenomena will appear, and the energy will be significantly reduced.Always feel exhausted.
7. The frequency of urination is high, and the fertilized egg begins to secrete chorionic gonadal hormone (HCG) after implantation in the uterine wall.Make urine increase and urinate more frequently.
8. Breast changes. After pregnancy, under the common stimulation of estrogen and progesterone, from the 8th week, the breast gradually grows up, the color of nipple and areola is deepened, and there are dark brown nodules around the nipple. After 12 weeks, a little clear water like milk will be secreted[1]。
