Healthy uterus. Functional changes during the monthly cycle

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The uterus is the most important organ female build. Thanks to her, childbearing becomes possible. It is in the uterus that the fertilized egg continues to develop, and at the end of the gestation period it contains a fully formed child.

Location of the uterus

We are talking about a hollow pear-shaped organ. Its natural location is in the pelvic area. Neighboring this organ are bladder and rectum. The uterus is slightly tilted forward. It is securely fixed in its position, but at the same time has sufficient mobility.

This is facilitated by special ligaments. They allow the organ to safely respond to environmental changes and at the same time occupy a comfortable position. For example, when fluid accumulates in the bladder, the uterus moves slightly back, and when the rectum is full, it rises.

The ligaments have a complex attachment. Its nature explains why pregnant women should not raise their arms high often. In this position, the ligaments are stretched, the uterus becomes tense and shifts. As a result, the fetus may take incorrect position, which is undesirable later gestation.

The weight of the uterus may change. After childbirth, it becomes heavier on its own. During pregnancy, the uterus, having elastic walls, increases many times over. It is capable of supporting a five-kilogram fetus. At the end of the childbearing period, the uterus shrinks, its tissues atrophy, and sclerotic changes occur in the blood vessels.

Organ structure

The uterus is formed by several sections.

Neck

This part is transitional between the vagina and the uterine cavity. It is a kind of muscular tube, making up approximately a third of the organ. The cervical canal runs inside. At the bottom, the neck ends in a pharynx. This hole is the entrance for sperm trying to penetrate the egg. Menstrual blood also flows through the throat.

The cervical canal is filled with a thick substance produced by its mucous membrane. One of the functions of such a "plug" is to kill harmful microorganisms, capable of affecting the uterus and its tubes. The latter open into the peritoneum. Therefore, mucus protects not only the uterus itself from infection, but also indirectly the internal organs.

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During ovulation, the substance in the canal becomes less dense. The environment of the cervix during this period is favorable for male cells and promotes their mobility. The same thing happens with mucus during menstruation. Such changes are necessary so that blood can flow out freely. In both situations considered, the female body becomes more vulnerable to infection. By the way, infection can also occur through sperm, therefore intimacy with an unfamiliar person is undesirable.

The shape of this part of the uterus is not always the same. Before birth, the cervix is ​​round in cross section and resembles a truncated cone. Women who have given birth experience changes in this area. The neck expands and takes on a cylindrical shape. The same thing happens after an abortion. During an examination, the gynecologist clearly sees these changes, so it is impossible to deceive him.

Isthmus

This short section connects the cervix to the main part of the cervix. During labor, the isthmus helps the tract widen so that the fetus can be successfully delivered. This is a vulnerable place where ruptures can occur.

Body of the uterus

Internal structural element This main part of the organ is the endometrium. The mucosal layer, as it is also called, has many vessels. The endometrium is very sensitive to the action of hormones. During the menstrual cycle, it prepares for pregnancy. If fertilization does not occur until a certain point, the endometrium partially exfoliates. These days it is observed menstrual bleeding. After part of the endometrium comes out, the growth of this uterine layer begins again to a certain limit.

At conception, the endometrium becomes a “nest” for the embryo. During this period, it is not rejected, obeying the changed action of hormones. Therefore, women carrying a child do not normally bleed. If discharge appears, this should alert you.

The middle layer in the body of the uterus is formed by muscles. They themselves are very strong, so much so that they are able to push out a grown fetus during childbirth. At this point, the muscles are further strengthened and reach their maximum development. This dense layer of the uterus also plays main role in protecting the fetus from shock.

The muscles of the organ are always in good shape. Their constant contraction and relaxation is observed. Muscle movements are especially intense in connection with sexual intercourse. Thanks to this, sperm travel safely to their destination. In addition, the uterus contracts more strongly during menstruation. This promotes successful endometrial shedding.

The body of the uterus also has an outer layer - the perimeter. The tissue it consists of is connective. Perimeter covers most organ. The exception is some areas in the area above the vagina.

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Uterine abnormalities

The organ may be in an incorrect position. There are also cases when the proportions of the uterus are disturbed or its size deviates greatly from the norm. Typically, such defects originate in the prenatal period. The reason for this is viral infections, taking certain medications, alcoholism and other factors. Examples of anomalies encountered:

• Unicornuate uterus. This pathology appears due to abnormal growth of the so-called Müllerian ducts. They are paired canals that form after approximately two months of embryonic development. A unicornuate uterus occurs when one of the ducts stops growing. Often, simultaneously with such an anomaly, defects of the urinary system are observed.
• Bicornuate uterus. In this state, the organ has two cavities. In addition, sometimes there is incomplete bicornuate uterus. In its outline, it resembles a heart - there is a common cavity, and the bottom - in the uterus this is the upper part - is, as it were, divided into two parts. The cause of the described conditions is the incomplete fusion of the same Müllerian ducts in their middle part.
• Saddle uterus. With such a pathology, a woman may not be bothered by any symptoms. But ultrasound and other research methods used reveal a saddle-shaped notch in the fundus. With such an anomaly of the uterus, there is a chance to carry a child normally and give birth to him. Along with this, there are often cases premature birth. May occur various pathologies placenta or abnormal fetal position.
• Hypoplasia of the uterus. This condition is characterized by the development of the organ in a reduced form. At the same time, the girl as a whole is lagging behind in development. She is too short in stature, has a narrow pelvis and greatly reduced breasts. A gynecologist can already identify this pathology during an examination. To confirm the diagnosis, an ultrasound is performed and hormone levels are determined.

Check the condition of your female organs you can always in our medical center"Euromedprestige". We can conduct full diagnostics, and when problems are identified, enlist the support of experienced doctors.

The uterus is an important part of the female reproductive system. It is she who serves to fulfill the main purpose of the fair sex - motherhood. Here the implantation of the fertilized egg and the development of the fetus occurs.

Woman's cervix. Location

The Russian name of this organ speaks volumes. The uterus is an important part of the female reproductive system.

It is she who serves to fulfill the main purpose of the fair sex - motherhood. Here the implantation of the fertilized egg and the development of the fetus occurs.

The uterus is located in the pelvis between the bladder and the rectum, fixed by ligaments, but retains relative mobility, which allows it to slightly change its position.

Most of the organ is covered by peritoneum. The shape of this muscular organ in women of reproductive age resembles a pear or triangle. Inside there is a cavity that communicates with fallopian tubes, and from below - with the vagina.

The expanded part is the body of the uterus, and the upper dome of which is usually called the bottom. The body can be tilted forward (Anteversio), backward (Retroversio) or to the side (Lateroversio). There is also an inflection of the uterine body relative to the cervix anteriorly, posteriorly, or to the lateral wall.

Retroflexion, or backward bending of the uterus, sometimes causes a lot of trouble for a woman. Downwards, the uterus narrows and passes into the isthmus, the thinnest place. For a number of reasons, uterine ruptures most often occur here during childbirth. And finally, the cervix. A narrow cervical canal runs through the center of the cervix.

At the level of the isthmus, the internal os opens directly into the uterine cavity; the external os opens into the vagina. The shape of the cervix and opening of the uterus is somewhat different between women before and after childbirth. In the first case, the neck is cylindrical with a rounded hole, in the second it resembles a cone, and the outer pharynx takes on a slit-like shape

Wall structure

The wall of the organ is represented by three layers. The perametrium, the serous membrane in the body area, is tightly fused to the underlying layer, and in the area of ​​the isthmus the connection is loose. The myometrium consists of smooth muscle, connective tissue and elastic fibers. There are three parts in this layer, although the division is quite arbitrary, because the fibers intertwine with each other in different directions.

At the confluence of the fallopian tubes and in the area of ​​the isthmus muscle fibers form rings like sphincters. The viability of the internal os directly determines the bearing of a pregnancy, and its timely, complete opening ensures the successful course of the birth act.

The muscles of the uterus are very developed, and during pregnancy, myocytes also hypertrophy, because they have an important mission - protecting the fetus during all 9 months of pregnancy from external influences and its expulsion during childbirth.

Muscles are constantly working. They react to sexual intercourse, promoting the movement of male gametes towards the egg, they tense during menstruation, ensuring the cleansing of the uterine cavity from blood and endometrial remains; during pregnancy, waves of contractions may occur due to cold, careless movement, pressure with a hand or an ultrasound probe on the abdominal wall .

Hypertrophy of smooth muscle cells underlies such a common pathology as uterine fibroids. The endometrium is the most inner layer, mucous membrane of the uterus. It is formed by single-layer columnar epithelium and is abundantly supplied with blood. In some parts of the uterus, the epithelium has cilia.

There are deep (basal) and superficial (functional) layers. The latter undergoes significant changes depending on the phase of the menstrual cycle; first it actively proliferates, then the fertilized egg is immersed in it.

If conception does not occur, then menstruation occurs and the functional layer is rejected. At the end of menstruation, the surface layer is regenerated due to the basal cells.

In the cervical canal, the epithelium forms folds, which contributes to the accumulation of mucus, which is secreted by glands located in the thickness of the mucous membrane. This plug protects against the penetration of vaginal contents, including pathogenic microbes, into the uterus.

At the onset of ovulation, the consistency of the cervical mucus becomes more liquid, the cervix becomes moisturized, all this facilitates the movement of sperm to the meeting place with the female reproductive gamete.

Decreased immunity, hypothermia, the presence of a good nutritional environment, for example, menstrual blood leads to the fact that the infection ascends into the uterus, causing a terrible disease - endometritis.

In the area of ​​the external pharynx, the epithelium changes to a multilayered squamous epithelium, which covers the walls of the vagina. It is here, on the vaginal part of the cervix, that cervical erosion, a fairly common pathology, can be found.

Development of the uterus in women.

The uterus is formed from the middle germ layer, the mesoderm. The neck and myometrial rudiments, which have transformed from the Müllerian ducts, can be detected as early as the sixth week of intrauterine development.

The fetal gonads appear and begin to function a little earlier. The Y chromosome contains the factor that determines male sex. In its absence, a female fetus is formed.

Fusion of the Müllerian ducts begins at the end of the 8th week. The uterus is fully formed only by the 20th week of gestation. The impact of unfavorable factors during the formation of organs leads to the fact that the child is born with a malformation of the uterus.

At first it is two-horned, at birth it is saddle-shaped, relatively large, in the first year it decreases by half and does not undergo any changes until the age of seven. Only in school age The uterus begins to gradually increase and reaches the size adult woman by the age of 20.

With the onset of menopause, the organ enters a phase of reverse development; changes are especially intense in the first months after the cessation of menstruation.

During sex.

The uterus is an organ located deep inside, it may seem that it “does not participate” in sexual contact men and women.

It's a delusion. During orgasm, the uterus seems to be drawn into the vagina, and the plug is pushed out. The cervix is ​​very sensitive.

A light touch of the head of the penis to the cervix gives both sexual partners amazing sensations. But a man’s rudeness, sharp and deep penetrations into the vagina cause pain in a woman. Unpleasant sensations and pain during intimate relationships can occur when inflammatory diseases reproductive system.

Pregnancy.

Carrying a child is a complex process. The uterus undergoes the most dramatic transformations within 40 weeks. Before pregnancy, the length of the organ is on average 7-8 cm, and by birth its size may be 37-38 cm.

The volume of the uterine cavity increases hundreds of times, and the weight of the organ increases by 10-20 times. After childbirth, all sizes also quickly return to those observed before conception.

The weight of the organ of a woman who has given birth is only slightly different from the weight of a nulliparous woman. To involution of the uterus in postpartum period many factors influence. If the mother is weakened, is over 30 years old, and has a history of many births, then her uterus contracts more slowly.

Breastfeeding, on the contrary, promotes the rapid restoration of the original size of the organ. Implantation of the embryo often occurs on back wall uterus.

But past infections, abortions, which have depleted the mucous membrane of the reproductive organ, can lead to the fact that the embryo is attached to a place not intended for bearing a pregnancy, for example, in fallopian tube.

Diagnosed ectopic pregnancy. The same reasons contribute to the incorrect, too low, location of the main feeding organ of the fetus. Placenta previa is a serious complication of pregnancy.

At the stage of gestation, the uterine mucosa is transformed into a thick decidua and is directly involved in the formation of the placenta.

With the onset of pregnancy, the cervix changes, which the doctor will certainly notice during examination. Before conception, it is pinkish in color, smooth and elastic, after - due to the developed vascular network a cyanotic tint appears. At the same time, the cervical glands rapidly grow.

And by the end of pregnancy, as gynecologists say, the cervix matures, becomes soft, shortens, the cervical canal and the internal os of the uterus expand. The appearance of such symptoms is much more ahead of schedule childbirth is a threat of termination of pregnancy.

Dear readers, we hope that the information presented in the article was useful to someone. Have you learned anything new about yourself?

Basic knowledge of anatomy and physiology can help a woman avoid problems during conception, pregnancy and childbirth, as well as prevent various diseases reproductive sphere. Therefore, it is useful to learn about such an important organ of the female reproductive system as the uterus: how it is structured and how it changes throughout life, during pregnancy and birth of a child.

What is the uterus and where is it located?

The uterus is an organ reproductive system in a woman, in which the fetus develops from the moment the fertilized egg leaves the fallopian tube until the birth of the child. Its shape resembles an inverted pear.

The uterus is located in the small pelvis between bladder and rectum. Its position may change during the day: when the urinary and digestive system it moves a little, and after urination or defecation it returns to its original place. But the most noticeable change in the position of the uterus is observed simultaneously with its growth during pregnancy, as well as after childbirth.

Structure of the uterus

Using an ultrasound of the uterus, you can see that it consists of three structural parts. The upper convex side is called the bottom, the middle widened part is called the body, and the lower narrow part is called the body.

The cervix consists of an isthmus, elongated cervical canal and vaginal part. The inside of the uterus is hollow. Its cavity communicates on the lower side with the lumen of the vagina, and on the sides with the canals of the fallopian tubes.

The organ wall is three-layered:

1 The outermost layer facing the pelvic cavity is called perimetry. This membrane is closely connected with the outer covers of the bladder and intestines and consists of connective tissue cells.

2 Middle, thickest layer – myometrium, includes three layers of muscle cells: outer longitudinal, circular and inner longitudinal - they are named after the direction of the muscle fibers.

3 Inner shell, endometrium, consists of a basal and functional layer (facing the uterine cavity). Contains epithelial cells and many glands in which uterine secretions are formed.

The cervix has more connective dense collagen tissue and fewer muscle fibers than other parts of the organ.

The wall of the uterus is penetrated by numerous blood vessels. Arterial blood saturated with oxygen, bring steam uterine arteries and internal branches iliac artery. They branch and give rise to smaller vessels that supply blood to the entire uterus and its appendages.

The blood that has passed through the capillaries of the organ is collected in larger vessels: uterine, ovarian and internal iliac veins. Except blood vessels, there are also lymphatics in the uterus.

The vital functions of uterine tissue are controlled by hormones endocrine system, as well as the nervous system. The wall of the uterus includes branches of the pelvic splanchnic nerves associated with the inferior hypogastric nerve plexus.

Ligaments and muscles of the uterus

In order for the uterus to maintain its position, it is held in the pelvic cavity by connective tissue ligaments, of which the most famous are:

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1 Paired broad ligaments of the uterus(right and left) are attached to the peritoneal membrane. Anatomically, they are connected to ligaments that fix the position of the ovaries.

2 Round ligament contains both connective tissue and muscle cells. It starts from the wall of the uterus, passes through the deep opening of the inguinal canal and connects with the tissue of the labia majora.

3 Cardinal ligaments connect the lower part of the uterus (near the cervix) with the urogenital diaphragm. This fixation protects the organ from displacement to the left or right.

Through ligaments, the uterus is connected to the fallopian tubes and ovaries, which ensures proper mutual arrangement organs of the female reproductive system.

In addition to the ligaments, correct location The pelvic organs, including the uterus, are supported by a set of muscles called the pelvic floor. The composition of its outer layer includes the ischiocavernosus, bulbospongiosus, superficial transverse and external muscles.

The middle layer is called the urogenital diaphragm, it contains the muscle that compresses urethra and deep transverse muscle. The internal pelvic diaphragm unites the pubococcygeus, ischiococcygeus and iliococcygeus muscles. Muscles pelvic floor prevent deformation of organs, which would lead to disruption of their blood supply and functions.

Uterus dimensions

When a girl is born, the length of her uterus is about 4 cm. It begins to increase at the age of 7. After the final formation of the reproductive system during puberty, the uterus reaches dimensions of 7-8 cm in length and 3-4 cm in width. Wall thickness in different parts organ and in different phases the menstrual cycle varies from 2 to 4 cm. Its weight in a nulliparous woman is about 50 g.

The most significant changes in the size of the uterus occur during pregnancy, when in 9 months it increases to 38 cm in length and up to 26 cm in diameter. Weight increases to 1-2 kg.

After childbirth, a woman’s uterus shrinks, but does not return to its original parameters: now its weight is approximately 100 g, and its length is 1-2 cm greater than before conception. These sizes remain throughout the entire childbearing period; after the second and subsequent births, no noticeable increase occurs.

When a woman's reproductive period ends and menopause occurs, the uterus decreases in size and weight, the wall becomes thinner, and the muscles and ligaments often weaken. Already 5 years after the end of menstruation, the organ returns to the size it was at birth.

Uterus during pregnancy

During each menstrual cycle in a woman reproductive age Periodic changes occur in the structure of the uterus. Most of all they affect the functional endometrium.

At the beginning of the cycle, a woman’s body prepares for the possibility of pregnancy, so the endometrium thickens and more blood vessels appear in it. The amount of discharge from the uterus increases, which supports the viability of sperm.

If conception does not take place, after the death of the egg released from the follicle, the functional layer is gradually destroyed under the influence of hormones, and during menstruation its tissues are rejected and removed from the uterine cavity. With the beginning of a new cycle, the endometrium is restored.

If the egg is fertilized and pregnancy occurs, continuous growth of the uterus begins. The thickness of the functional endometrium increases: it is no longer rejected, because menstruation has stopped. The layer is further penetrated big amount capillaries and is supplied with blood more abundantly in order to provide the organ itself (which is growing rapidly) and the baby developing in the uterine cavity with oxygen and nutrients.

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The volume of the myometrium also increases. Its spindle cells divide, elongate and increase in diameter. The layer reaches its maximum thickness (3-4 cm) approximately in the middle of pregnancy, and closer to childbirth it stretches and because of this becomes thinner.

During regular examinations, starting from the 13-14th week of pregnancy, the gynecologist determines the height of the uterine fundus. By this time, its upper part, due to the increase in the size of the organ, extends beyond the pelvis.

By week 24, the fundus of the uterus reaches the level of the navel, and at week 36 its height is maximum (palpable between the costal arches). Then, despite the further growth of the abdomen, the uterus begins to descend due to the baby moving down, closer to the birth canal.

The cervix during pregnancy is thickened and has a bluish tint. Its lumen is covered with a mucous plug, which protects the uterine cavity from infections and other unfavorable factors (read about the removal of the plug on the website). Due to the rapid growth of the uterus and displacement from its usual place, its ligaments are stretched. In this case, pain may occur, especially in the third trimester and with sudden body movements.

Contraction of the uterus during pregnancy and childbirth

The myometrium (middle, thickest layer of the uterus) contains cells smoothly muscle tissue. Their movements cannot be controlled consciously; the process of fiber contraction occurs under the influence of hormones (primarily oxytocin) and vegetative nervous system. The muscle fibers of the myometrium contract during menstruation: this ensures the expulsion of secretions from the uterine cavity.

During pregnancy, the uterus also sometimes contracts. Its surface hardens, and the pregnant woman may feel pain or heaviness in the abdomen.

This happens either due to a threat (hypertonicity) or during pregnancy, which periodically occurs when carrying a child and prepares the myometrium for labor.

Not every woman understands exactly where the organs of her reproductive system are located. Therefore, when pain occurs, representatives of the fair sex often cannot understand what is bothering them. Many of them do not know where the uterus is. But this is one of the the most important organs women performing many functions. Let's look at this issue in more detail.

Structure and physiological changes of the uterus

The pelvic cavity is where the uterus is located. It is located at the bottom abdominal area. What does the uterus look like? Normally, it looks like an inverted pear. This is a cavity organ, the wall of which consists mainly of muscle tissue up to 3 cm thick. In front of it is the bladder. The posterior part is in contact with the anterior surface of the rectum.

The pelvic and uterine axis are in the same plane, which is considered normal occurrence. In addition, it may be slightly inconsistent. This is also not a pathology and does not require action.

The location of the uterus is influenced by the ligaments located on the sides and performing the function of holding it in the required position. It is considered a pathology strong deviation organ from the pelvic axis. It can descend, fall out, be located behind the rectum, or bend.

The weight of the uterus in a nulliparous woman does not exceed 50 grams. After the birth of a child, it increases one and a half to two times, reaching 100 g. In addition, the size of the organ matters. Its length in women who do not have children is approximately 7 cm and its width is 4 cm. During pregnancy, the uterus stretches. After childbirth, it shrinks, but it no longer decreases to its previous size. The longitudinal and transverse dimensions increase by 2-3 cm.

The uterus consists of the fundus, body and cervix. The fundus is the area located above the conventional line passing through the fallopian tubes. The body of the organ in a triangular section starts from the fundus and continues to the uterine constriction.

The cervix is ​​a continuation of the previous part and makes up the entire rest of the uterus. It opens into the vagina and consists of three parts - anterior, posterior and a section located above the vagina. The latter, in women who do not have children, resembles a cut cone, and in those who have given birth, it is cylindrical in shape.

The inside of the neck is covered by a layer of epithelium. The part that is visible in the vaginal cavity is covered by stratified squamous epithelium, which is not prone to keratinization. The rest of the segment is lined with glandular epithelial cells.

The place of transition from one species to another is important clinical significance. Dysplasia often occurs in this area, which, if left untreated, can turn into a cancerous tumor.

The frontal section of the organ is similar to a triangle. Its acute angle is directed downwards. A fallopian tube opens into the uterus on each side. The base of the triangle passes into the cervical canal, preventing the release of mucus produced by the glandular epithelium. This secret has antiseptic property and kills bacteria heading into abdominal cavity. The cervical canal has two openings. One protrudes into the uterus, the second into the vaginal cavity.

The cervical canal is round or resembles a transverse slit. The place where the body meets the neck is called the isthmus. Here, a woman's uterus often ruptures during the birthing process.

The uterine wall has three layers: the outer layer is the serous membrane, the middle layer is the muscle fibers that form the basis of the organ, and the inner layer is the mucous membrane. In addition, parametrium is distinguished - this is fatty tissue, which is located in front and on the side of the uterus, in the space between the sheets of the largest ligament. It contains vessels that provide nutrition to the organ.

Contractility is influenced by sex hormones. Exactly muscle layer ensures the birth of a child. The internal pharynx and isthmus also play a certain role in this process.

The mucous layer (endometrium) is covered with epithelial cells. It is smooth and divided into two sublayers. The surface sublayer has a variable thickness. Before menstruation, it is rejected, which is accompanied by bleeding.

Important surface layer and for bearing a fetus. The fertilized egg is attached to it. The basal sublayer is like the base of the mucous layer. Its function is to ensure the restoration of the surface epithelium. It contains tubular glands that reach the muscle fibers.

The serosa is the outer covering layer of a woman's uterus. It lines the muscles of the bottom and body outside. On the sides it passes to other organs.

It forms a vesicouterine cavity near the bladder. The connection with it is carried out through fiber. At the back, the peritoneum passes onto the vagina and rectum, forming the rectouterine cavity. It is closed by serous folds, which consist of connective tissue cells. They also contain some smooth muscle fibers.

Functions of the uterus and deviations in its structure

The main function of a woman's uterus is the ability to bear a fetus. It is provided by the muscles of the middle layer. It contains smooth muscle fibers that intertwine with each other. This structure allows the muscles to stretch during pregnancy as the fetus grows. In this case, there is no violation of tone.

The female uterus and the ligaments surrounding it are supplied by the uterine and ovarian arteries. The outflow is carried out by the venous uterine plexus, which is located in the broad ligament. Out of him blood is flowing into the ovarian, uterine and internal sacral vein.

During gestation, these vessels can expand significantly, allowing the absorption of placental blood. Lymph flows into the external iliac and inguinal nodes. Innervation is carried out by many nerves.

In addition to ensuring implantation and fetal development, a healthy uterus performs the following functions:

• protects other organs of the pelvic cavity from infection through the vagina;
• provides menstrual function;
• participates in sexual intercourse, creating conditions for fertilization of the egg;
• strengthens the pelvic floor.

Along with the uterus of a normal (pear-shaped) shape, there are also anomalous species. These include:

A unicornuate uterus occurs in every tenth woman with a developmental anomaly. It is formed as a result of slowing down the growth of the Müllerian ducts on one side. Half of patients with this diagnosis cannot have children. They also experience pain during intimacy.

A bicornuate uterus develops due to incomplete fusion of the Müllerian ducts. Often it is bilobed. In rare cases, two cervixes are observed. The vagina sometimes has a septum. In appearance, such a uterus resembles a heart.

The saddle shape is quite common. In this case, a saddle-shaped depression is formed in the bottom. This abnormal structure often does not cause any symptoms. May appear during pregnancy. Sometimes patients with a saddle uterus bear a child without problems. But there are also miscarriages or premature births.

A double uterus usually does not cause much trouble. The presence of two vaginas can be observed at the same time. Fetal development is possible in both uteruses.

A uterus whose length does not exceed 8 cm is considered small. At the same time, the proportions of the body and cervix, as well as all functions of the uterus, are preserved.

The infantile uterus is 3-5 cm long. The ratio of the body and cervix is ​​incorrect, the latter is elongated. The rudimentary uterus is the remains of an organ that in most cases does not perform its function.

The uterus is one of the main organs female body. In its cavity, fertilization and development of the unborn child occurs. Thanks to this, she actually ensures continuation of the family.

Uterus (from lat. uterus, metra) is an unpaired hollow muscular organ in which the fetus develops during pregnancy. The uterus, as well as the ovaries, fallopian tubes and vagina are classified as internal female genital organs.

Location and shape of the uterus

The uterus is located in the pelvic cavity between the bladder in front and the rectum in back. The shape of the uterus has been compared to a pear, flattened from front to back. Its length is about 8 cm, weight 50-70 g. The uterus is divided into a body, an upper convex part - the bottom and a lower narrowed part - the cervix. The cervix juts out into top part vagina. In a newborn girl, the cervix is ​​longer than the body of the uterus, but during puberty the body of the uterus grows faster and reaches 6-7 cm, the cervix - 2.5 cm. old age the uterus atrophies and noticeably decreases.

The body of the uterus forms an angle with the cervix, open anteriorly (towards the bladder) - this is a normal physiological position. The uterus is held in place by several ligaments, the main of which - the broad ligaments of the uterus - are located on its sides and pass to side walls pelvis Depending on the filling of neighboring organs, the position of the uterus may change. So, when the bladder is full, the uterus deviates posteriorly and straightens. Constipation and intestinal fullness also affect the position and condition of the uterus. That is why it is important for a woman to empty both her bladder and rectum on time.

The uterine cavity is small compared to the size of the organ and on the section it has triangular shape. The openings of the fallopian tubes open into the corners of the base of the triangle (at the border between the fundus and the body of the uterus). Downwards, the uterine cavity passes into the cervical canal, which opens into the vaginal cavity through the opening of the uterus. U nulliparous women this hole has a round or oval shape; in those who have given birth, it looks like a transverse slit with healed tears.

Structure of the uterine wall

The wall of the uterus consists of 3 membranes: the inner - mucous (endometrium), the middle - muscular (myometrium) and the outer - serous (perimetry), represented by the peritoneum.

The structure of the endometrium
The mucous membrane of the uterus is covered with ciliated epithelium and has simple tubular glands. With the onset of puberty, it undergoes periodic changes associated with the maturation of eggs - female germ cells - in the ovary. A mature egg is sent from the surface of the ovary through the fallopian tube into the uterine cavity. If fertilization of the egg occurs in the fallopian tube (the fusion of the egg and sperm - the male reproductive cell), then the embryo that has begun to form is embedded in the mucous membrane of the uterus, where it occurs further development, that is, pregnancy begins. At the 3rd month of pregnancy, the placenta, or baby's place, forms in the uterus - special education, through which the fetus receives nutrients and oxygen from the mother's body.

In the absence of fertilization, the endometrium undergoes complex cyclic changes, which are commonly called menstrual cycle. At the beginning of the cycle there are structural transformations, aimed at preparing the endometrium to receive a fertilized egg: the thickness of the endometrium increases 4-5 times, its blood supply increases. If fertilization of the egg does not occur, menstruation occurs - the rejection of the surface part of the endometrium and its removal from the body along with the unfertilized egg. The menstrual cycle lasts about 28 days, of which 4-6 days are occupied by menstruation itself. In the postmenstrual phase (up to the 11-14th day from the start of menstruation), a new egg matures in the ovary, and the surface layer of the mucous membrane is restored in the uterus. Next next premenstrual phase characterized by a new thickening of the uterine mucosa and its preparation to receive a fertilized egg (from the 14th to the 28th day).

Cyclic changes in the structure of the endometrium occur under the influence of ovarian hormones. In the ovary, in place of the matured egg that has reached the surface, the so-called corpus luteum develops. In the absence of fertilization of the egg, it exists for 12-14 days. If the egg is fertilized and pregnancy occurs, the corpus luteum remains for 6 months. Cells corpus luteum produce the hormone progesterone, which affects the condition of the uterine mucosa and the restructuring of the mother’s body during pregnancy.

The structure of the myometrium
The muscular lining of the uterus, the myometrium, makes up its main mass and has a thickness of 1.5 to 2 cm. The myometrium is built from smooth muscle tissue, the fibers of which are arranged in 3 layers (outer and inner - longitudinal, middle, the most powerful, - circular). During pregnancy, myometrial fibers greatly increase in size (up to 10 times in length and several times in thickness), so by the end of pregnancy the weight of the uterus reaches 1 kg. The shape of the uterus becomes rounded, and the length increases to 30 cm. Everyone can imagine the changes in the size of the belly of a pregnant woman. Such a powerful development of the muscular lining of the uterus is necessary for childbirth, when the ripe fetus is removed from the mother’s body by contraction of the uterus and muscles abdominals. After childbirth, the uterus undergoes reverse development, which ends after 6-8 weeks.

Thus, the uterus is an organ that changes periodically throughout life, which is associated with the menstrual cycle, pregnancy and childbirth.

The structure of the uterus: options outside the norm

Interesting data about individual options shape and position of the uterus. The absence of half the uterus, complete or partial closure of the uterine cavity are described. Duplication of the uterus and the presence of a septum in its cavity are extremely rare. Sometimes the septum is present only in the area of ​​the uterine fundus and is expressed in varying degrees(saddle-shaped, bicornuate uterus). The septum may extend to the vagina. The uterus often remains small, not reaching adult size (infantile uterus), which is combined with underdevelopment of the ovaries.

All these variants of the structure of the uterus are associated with the peculiarities of its development in the embryo from 2 tubes merging with each other (Müllerian ducts). Non-fusion of these ducts leads to doubling of the uterus and even the vagina, and a delay in the development of one of the ducts underlies the appearance of an asymmetrical, or one-horned, uterus. Failure of fusion of the ducts along one or another section leads to the appearance of partitions in the cavity of the uterus and vagina.

Rudiment of the male body: prostatic uterus

Men also have a utricle - a pinpoint depression on the wall of the urethra in its prostatic part, not far from the place where the vas deferens enters the urethra. This prostatic uterus is a vestigial remnant of the Müllerian ducts, which are formed in the embryo, but in male body they just don't develop.