The fallopian tubes. Fallopian tubes - structure and functions The wall of the fallopian tube consists of 3 membranes

The fallopian tubes (oviducts, Fallopian tubes) are paired organs through which the egg passes from the ovaries to the uterus.

Development. The fallopian tubes develop from the upper part of the paramesonephric ducts (Müllerian canals).

Structure. The wall of the oviduct has three membranes: mucous, muscular and serous. The mucous membrane is collected in large branched longitudinal folds. It is covered with a single-layer prismatic epithelium, which consists of two types of cells - ciliated and glandular, secreting mucus. The lamina propria of the mucous membrane is composed of loose fibrous connective tissue. The muscular layer consists of an internal circular or spiral layer and an external longitudinal one. On the outside, the oviducts are covered with a serous membrane.

The distal end of the oviduct expands into a funnel and ends with a fimbriae (fimbriae). At the time of ovulation, the vessels of the fimbriae increase in volume and the funnel tightly covers the ovary. The movement of the germ cell along the oviduct is ensured not only by the movement of the cilia of the epithelial cells lining the cavity of the fallopian tube, but also by peristaltic contractions of its muscular membrane.

Uterus

The uterus (uterus) is a muscular organ designed to carry out the intrauterine development of the fetus.

Development. The uterus and vagina develop in the embryo from the distal portion of the left and right paramesonephric ducts at their confluence. In this regard, at first the body of the uterus is characterized by some bicornuity, but by the 4th month of intrauterine development the fusion ends and the uterus acquires a pear-shaped shape.

Structure. The wall of the uterus consists of three membranes:

mucous membrane - endometrium;

muscular membrane - myometrium;

serous membrane - perimetry.

The endometrium has two layers - basal and functional. The structure of the functional (superficial) layer depends on ovarian hormones and undergoes deep restructuring throughout menstrual cycle. The mucous membrane of the uterus is lined with single-layer prismatic epithelium. As in fallopian tubes ah, ciliated and glandular epithelial cells are isolated here. Ciliated cells are located mainly around the mouths of the uterine glands. The lamina propria of the uterine mucosa is formed by loose fibrous connective tissue.

Some cells connective tissue develop into special decidual cells of large size and round shape. Decidual cells contain lumps of glycogen and lipoprotein inclusions in their cytoplasm. The number of decidual cells increases during the formation of the placenta during pregnancy.

The mucous membrane contains numerous uterine glands, extending through the entire thickness of the endometrium and even penetrating into the superficial layers of the myometrium. The shape of the uterine glands is simple tubular.

The second lining of the uterus - the myometrium - consists of three layers of smooth muscle cells - the internal submucosal layer (stratumsubmucosum), the middle vascular layer with an oblique longitudinal arrangement of myocytes (stratumvasculosum), rich in blood vessels, and the external supravascular layer (stratumsupravasculosum) also with an oblique longitudinal arrangement of muscle cells, but cross in relation to to the vascular layer. This arrangement of muscle bundles has a certain significance in regulating the intensity of blood circulation during the menstrual cycle.

Between the bundles of muscle cells there are layers of connective tissue, replete with elastic fibers. Smooth muscle cells of the myometrium, about 50 microns in length, greatly hypertrophy during pregnancy, sometimes reaching a length of 500 microns. They branch slightly and are connected by processes into a network.

The perimeter covers most of the surface of the uterus. Only the anterior and lateral surfaces of the supravaginal part of the cervix are not covered by peritoneum. The mesothelium lying on the surface of the organ and loose fibrous connective tissue, which make up the layer adjacent to the muscular lining of the uterus, take part in the formation of perimetry. However, this layer is not the same in all places. Around the cervix, especially on the sides and front, there is a large accumulation of adipose tissue, which is called pyrometry. In other parts of the uterus, this part of the perimeter is formed by a relatively thin layer of loose fibrous connective tissue.

Cervix (cervixuteri)

The mucous membrane of the cervix is covered, like the vagina, with stratified squamous epithelium. The cervical canal is lined with prismatic epithelium, which secretes mucus. However, the largest amount of secretion is produced by numerous relatively large branched glands located in the stroma of the folds of the mucous membrane of the cervical canal. The muscular layer of the cervix is represented by a thick circular layer of smooth muscle cells, which makes up the so-called uterine sphincter, during the contraction of which the mucus is squeezed out of the cervical glands. When this muscle ring relaxes, only a kind of aspiration (suction) occurs, facilitating the retraction of sperm that has entered the vagina into the uterus.

Features of blood supply and innervation

Vascularization. The uterine blood supply system is well developed. The arteries that carry blood to the myometrium and endometrium are spirally twisted in the circular layer of the myometrium, which contributes to their automatic compression during contraction of the uterus. This feature becomes especially important during childbirth, since the possibility of strong uterine bleeding due to separation of the placenta.

Entering the endometrium, the afferent arteries give rise to small arteries of two types, some of them, straight, do not extend beyond the basal layer of the endometrium, while others, spiral, supply blood to the functional layer of the endometrium.

Lymphatic vessels in the endometrium form a deep network, which, through the lymphatic vessels of the myometrium, connects to the external network located in the perimetry.

Innervation. The uterus receives nerve fibers, mainly sympathetic, from the hypogastric plexus. On the surface of the uterus in the perimetry, these sympathetic fibers form a well-developed uterine plexus. From this superficial plexus branch branches supply the myometrium and penetrate the endometrium. Near the cervix in the surrounding tissue there is a group of large ganglia, in which, in addition to sympathetic nerve cells, there are chromaffin cells. There are no ganglion cells in the thickness of the myometrium. IN Lately Data have been obtained indicating that the uterus is innervated by both sympathetic and some parasympathetic fibers. At the same time, a large number of receptors were found in the endometrium nerve endings different structures, the irritation of which not only causes changes in the functional state of the uterus itself, but also affects many general functions of the body: blood pressure, respiration, general metabolism, hormone-forming activity of the pituitary gland and other endocrine glands, and finally, the activity of the central nervous system, in particular the hypothalamus.

Lecture 29: Female reproductive system.

Sources, formation and development of the organs of the female reproductive system.

Histological structure, histophysiology of the ovaries.

Histological structure of the uterus and oviducts.

Histological structure, regulation of mammary gland functions.

Embryonic development of the organs of the female reproductive system. The organs of the female reproductive system develop from the following sources:

a) coelomic epithelium covering the first kidney (splanchnotomes)  follicular cells of the ovaries;

b) endoderm of the yolk sac  oocytes;

c) mesenchyme  connective tissue and smooth muscles of organs, interstitial cells of the ovaries;

d) paramesonephric (Müllerian) duct  epithelium of the fallopian tubes, uterus and parts of the vagina.

The formation and development of the reproductive system is closely connected with the urinary system, namely with the first kidney. The initial stage of the formation and development of organs of the reproductive system in females and males proceeds in the same way and is therefore called the indifferent stage. At the 4th week of embryogenesis, the coelomic epithelium (visceral layer of splanchnotomes) on the surface of the first kidney thickens - these thickenings of the epithelium are called genital ridges. Primary germ cells, gonoblasts, begin to migrate into the genital ridges. Gonoblasts first appear as part of the extraembryonic endoderm of the yolk sac, then they migrate into the wall hindgut, and there they enter the bloodstream and reach through the blood and penetrate into the genital ridges. Subsequently, the epithelium of the genital ridges, together with gonoblasts, begins to grow into the underlying mesenchyme in the form of cords - they are formed sex cords. The reproductive cords consist of epithelial cells and gonoblasts. Initially, the sex cords retain contact with the coelomic epithelium, and then break away from it. Around the same time, the mesonephric (Wolffian) duct (see embryogenesis of the urinary system) splits and the paramesanephric (Müllerian) duct is formed parallel to it, which also flows into the cloaca. This is where the indifferent stage of development of the reproductive system ends.

As the mesenchyme grows, it divides the sex cords into separate fragments or segments - the so-called egg balls. In the oviparous balls, gonocytes are located in the center, surrounded by epithelial cells. In the egg-bearing balls, gonocytes enter the first stage of oogenesis - the stage of reproduction: they begin to divide by mitosis and turn into Oogonia, and the surrounding epithelial cells begin to differentiate into follicular cells. The mesenchyme continues to crush the egg-bearing balls into even smaller fragments until 1 remains in the center of each fragment. sex cell, surrounded by 1 layer of flat follicular cells, i.e. is being formed premordial follicle. In premordial follicles, oogonia enter the growth stage and transform into oocytesIorder. Soon the growth of first order oocytes in the premordial follicles stops and subsequently the premordial follicles remain unchanged until puberty. The combination of premordial follicles with layers of loose connective tissue between them forms the ovarian cortex. The surrounding mesenchyme forms a capsule, connective tissue layers between the follicles and interstitial cells in the cortex and connective tissue of the medulla of the ovaries. From the remaining part of the coelomic epithelium of the genital ridges, the outer epithelial cover of the ovaries is formed.

The distal parts of the paramesonephric ducts come together, merge and form the epithelium of the uterus and parts of the vagina (if this process is disrupted, the formation of a bicornuate uterus is possible), and the proximal parts of the ducts remain separate and form the epithelium of the fallopian tubes. From the surrounding mesenchyme, connective tissue is formed as part of all 3 membranes of the uterus and fallopian tubes, as well as the smooth muscles of these organs. The serous membrane of the uterus and fallopian tubes is formed from the visceral layer of splanchnotomes.

II.Histological structure and histophysiology of the uterus. On the surface, the organ is covered with mesothelium and a capsule of dense, unformed fibrous connective tissue. Under the capsule is the cortex, and in the central part of the organ is the medulla. The cortex of the ovaries of a sexually mature woman contains follicles of different stages development, atretic bodies, corpus luteum, corpus alba and layers of loose connective tissue with blood vessels between the listed structures.

Follicles. The cortex mainly consists of many premordial follicles - in the center there are first-order oocytes, surrounded by a single layer of flat follicular cells. With the onset of puberty, premordial follicles, under the influence of the adenohypophysis hormone FSH, take turns entering the maturation path and go through the following stages:

The first order oocyte enters the phase of large growth, increases in size approximately 2 times and acquires secondary – zona pellucida(both the egg itself and follicular cells are involved in its formation); the surrounding follicular ones transform from a single-layer flat first to a single-layer cubic, and then to a single-layer cylindrical. This follicle is called Ifollicle.

Follicular cells multiply and from a single-layer cylindrical become multi-layered and begin to produce follicular fluid (contains estrogens), which accumulates in the developing cavity of the follicle; An oocyte of the first order, surrounded by I and II (pellucid) membranes and a layer of follicular cells, is pushed to one pole (oviferous tubercle). This follicle is called IIfollicle.

The follicle accumulates a lot of follicular fluid in its cavity, therefore it greatly increases in size and protrudes on the surface of the ovary. This follicle is called IIIfollicle(or vesicular or Graafian bubble). As a result of stretching, the thickness of the wall of the third follicle and the covering albuginea of the ovary sharply thins. At this time, the first-order oocyte enters the next stage of oogenesis - the maturation stage: the first meiotic division occurs and the first-order oocyte turns into a second-order oocyte. Next, the thinned wall of the follicle and the tunica albuginea rupture and ovulation occurs - an oocyte of the second order, surrounded by a layer of follicular cells (corona radiata) and membranes I and II, enters the peritoneal cavity and is immediately captured by fimbriae (fimbriae) into the lumen of the fallopian tube.

In the proximal part of the fallopian tube, the second division of the maturation stage quickly occurs and the second-order oocyte turns into a mature egg with a haploid set of chromosomes.

The ovulation process is regulated by the adenohypophysis hormone lutropin.

As the premordial follicle begins to enter the maturation path, an outer shell gradually forms from the surrounding loose connective tissue around the follicle - theca or tire. Its inner layer is called vascular theca(has many blood capillaries) and contains interstitial cells that produce estrogens, and the outer layer of the theca consists of dense, irregular connective tissue and is called fibrous theca.

Yellow body. After ovulation, at the site of the burst follicle, under the influence of the adenohypophysis hormone lutropin, the corpus luteum is formed in several stages:

Stage I – vascularization and proliferation. Blood pours into the cavity of the ruptured follicle, and the blood clot grows blood vessels(hence the word “vascularization” in the title); At the same time, multiplication or proliferation of follicular cells in the wall of the former follicle occurs.

Stage II – ferruginous metamorphosis(rebirth or restructuring). Follicular cells turn into luteocytes, and interstitial thecal cells turn into thecal luteocytes and these cells begin to synthesize the hormone progesterone.

Stage III – dawn. The corpus luteum reaches a large size (diameter up to 2 cm) and progesterone synthesis reaches a maximum.

IV stage – reverse development. If fertilization has not occurred and pregnancy has not begun, then 2 weeks after ovulation the corpus luteum (called the menstrual corpus luteum) undergoes reverse development and is replaced by a connective tissue scar - it is formed white body (corpus albicans). If pregnancy occurs, the corpus luteum increases in size to 5 cm in diameter (corpus luteum of pregnancy) and functions during the first half of pregnancy, i.e. 4.5 months.

The hormone progesterone regulates the following processes:

Prepares the uterus to receive the embryo (the thickness of the endometrium increases, the number of decidual cells increases, the number and secretory activity of the uterine glands increases, the contractile activity of the uterine muscles decreases).

Prevents subsequent premordial ovarian follicles from entering the maturation pathway.

Atretic bodies. Normally, several premordial follicles simultaneously enter the maturation path, but most often 1 follicle matures to the third follicle, the rest undergo reverse development at different stages of development - atresia(under the influence of the hormone gonadocrinin, produced by the largest of the follicles) and in their place are formed atretic bodies. With atresia, the egg dies, leaving behind a deformed, wrinkled zona pellucida in the center of the atretic body; follicular cells also die, but the interstitial cells of the tegmentum multiply and begin to actively function (estrogen synthesis). Biological significance atretic bodies: prevention of superovulation - the simultaneous maturation of several eggs and, as a consequence, the conception of several fraternal twins; endocrine function - in the initial stages of development, one growing follicle cannot create the required level of estrogen in female body, therefore atretic bodies are necessary.

Histological structure of the uterus. The uterus is a hollow muscular organ in which the embryo develops. The wall of the uterus consists of 3 membranes - endometrium, myometrium and perimeter.

Endometrium (mucous membrane)– lined with single-layer prismatic epithelium. The epithelium is immersed in the underlying lamina propria of loose fibrous connective tissue and forms the uterine glands - simple tubular unbranched glands in structure. In the lamina propria, in addition to the usual cells of loose connective tissue, there are decidual cells - large round cells rich in glycogen and lipoprotein inclusions. Decidual cells take part in providing histotrophic nutrition to the embryo during the first time after implantation.

There are features in the blood supply to the endometrium:

Arteries - have a spiral course - this structure of the arteries is important during menstruation:

spastic contraction of the spiral arteries leads to malnutrition, necrosis and rejection of the functional layer of the endometrium during menstruation;

Such vessels thrombose faster and reduce blood loss during menstruation.

Veins - form expansions or sinuses.

In general, the endometrium is divided into a functional (or receding) layer and a basal layer. When determining the approximate boundary between the functional and basal layers, the main reference point is the uterine glands - the basal layer of the endometrium covers only the very bottoms of the uterine glands. During menstruation, the functional layer is rejected, and after menstruation, under the influence of estrogens of the follicle, due to the preserved epithelium of the bottoms of the uterine glands, regeneration of the uterine epithelium occurs.

Myometrium (muscular membrane) The uterus has 3 layers of smooth muscle:

Inner – submucosal layer.

The middle layer is the vascular layer.

The outer layer is the supravascular layer.

Perimetry– the outer lining of the uterus, represented by connective tissue covered with mesothelium.

The functions of the uterus are regulated by hormones: oxytocin from the anterior part of the hypothalamus - muscle tone, estrogens and progesterone from the ovaries - cyclical changes in the endometrium.

Fallopian tubes (oviducts)– have 3 shells:

The mucous membrane is lined with a single-layer prismatic ciliated epithelium, beneath it is the lamina propria of loose fibrous connective tissue. The mucosa forms large branched longitudinal folds.

The muscular layer consists of longitudinally and circularly oriented myocytes.

The outer shell is serous.

Mammary gland. Since the function and regulation of functions is closely related to the reproductive system, the mammary glands are usually studied in the section on the female reproductive system.

The mammary glands are complex in structure, branched alveolar glands; consist of secretory sections and excretory ducts.

Terminal secretory sections in the non-lactating mammary gland they are represented by blindly ending tubes - alveolar mammary ducts. The wall of these alveolar mammary ducts is lined with low-prismatic or cuboidal epithelium, with branched myepithelial cells lying on the outside.

With the onset of lactation, the blind end of these alveolar milk ducts expands and takes the form of vesicles, i.e. turns into alveoli. The alveolar wall is lined with one layer of low-prismatic cells—lactocytes. At the apical end, lactocytes have microvilli; granular and agranular EPS, a lamellar complex and mitochondria, microtubules and microfilaments are well expressed in the cytoplasm. Lactocytes secrete casein, lactose, and fats in an apocrine manner. From the outside, the alveoli are covered by stellate myoepithelial cells, which promote secretion into the ducts.

Milk is secreted from the alveoli into milky ducts (2-row epithelium), which further in the interlobular septa continue into the milk ducts (2-layer epithelium), flowing into the milk sinuses (small reservoirs lined with 2-layer epithelium) and short excretory ducts open at the apex of the nipple.

Regulation of mammary gland functions:

Prolactin (adenohypophysis hormone) – enhances milk synthesis by lactocytes.

Oxytocin (from the supraoptic paraventricular nuclei of the hypothalamus) - causes the secretion of milk from the gland.

Glucocorticoids from the zona fasciculata of the adrenal gland and thyroxine from the thyroid gland also promote lactation.

Organs of the female reproductive system include: 1) internal(located in the pelvis) - female gonads - ovaries, fallopian tubes, uterus, vagina; 2) external- pubis, labia minora and majora and clitoris. They reach full development with the onset of puberty, when their cyclic activity is established (ovarian-menstrual cycle), which continues during the woman’s reproductive period and ceases with its completion, after which the organs of the reproductive system lose their function and atrophy.

Ovary

Ovary performs two functions - generative(formation of female reproductive cells - ovogenesis) And endocrine(synthesis of female sex hormones). On the outside he is dressed cubic superficial epithelium(modified mesothelium) and consists of cortical And medulla(Fig. 264).

Ovarian cortex - wide, not sharply separated from the brain. Its bulk consists of ovarian follicles, formed by germ cells (ovocytes), which are surrounded by follicular epithelial cells.

Ovarian medulla - small, contains large convoluted blood vessels and special chyle cells.

Ovarian stroma represented by dense connective tissue tunica albuginea, lying under the surface epithelium, and a peculiar spindle cell connective tissue, in which spindle-shaped fibroblasts and fibrocytes are densely arranged in the form of swirls.

Oogenesis(except for the final stage) occurs in the ovarian cortex and includes 3 phases: 1) reproduction, 2) growth and 3) maturation.

Breeding phase Oogonia occurs in utero and is completed before birth; Most of the resulting cells die, the smaller part enters the growth phase, turning into primary oocytes, the development of which is blocked in prophase I of the meiotic division, during which (as during spermatogenesis) an exchange of chromosome segments occurs, providing genetic diversity of gametes.

Growth phase The oocyte consists of two periods: small and large. The first is noted before puberty in the absence of hormonal stimulation.

simulations; the second occurs only after it under the influence of follicle-stimulating hormone (FSH) of the pituitary gland and is characterized by the periodic involvement of follicles in cyclic development, culminating in their maturation.

Maturation phase begins with the resumption of division of primary oocytes in mature follicles immediately before the onset of ovulation. Upon completion of the first division of maturation, secondary oocyte and a small cell, almost devoid of cytoplasm - first polar body. The secondary oocyte immediately enters the second division of maturation, which, however, stops at metaphase. During ovulation, the secondary oocyte is released from the ovary and enters the fallopian tube, where, in the case of fertilization by sperm, it completes the maturation phase with the formation of a haploid mature female reproductive cell (ovules) And second polar body. The polar bodies are subsequently destroyed. In the absence of fertilization, the germ cell undergoes degeneration at the secondary oocyte stage.

Oogenesis occurs with constant interaction of developing germ cells with epithelial cells in the follicles, changes in which are known as folliculogenesis.

Ovarian follicles immersed in the stroma and consist of primary oocyte, surrounded by follicular cells. They create the microenvironment necessary to maintain the viability and growth of the oocyte. Follicles also have an endocrine function. The size and structure of the follicle depend on the stage of its development. There are: primordial, primary, secondary And tertiary follicles(see Fig. 264-266).

Primordial follicles - the smallest and most numerous, located in the form of clusters under the tunica albuginea and consist of small primary oocyte, surrounded single-layer squamous epithelium (follicular epithelial cells).

Primary follicles consist of larger primary oocyte, surrounded one layer of cubic or columnar follicular cells. Between the oocyte and follicular cells it first becomes noticeable transparent shell, having the appearance of a structureless oxyphilic layer. It consists of glycoproteins, is produced by the oocyte and helps to increase the surface area of the mutual exchange of substances between it and the follicular cells. As further

As follicles grow, the thickness of the transparent membrane increases.

Secondary follicles contain continuing to grow primary oocyte, surrounded by a shell of multilayer cuboidal epithelium, whose cells divide under the influence of FSH. A significant number of organelles and inclusions accumulate in the cytoplasm of the oocyte; cortical granules, which further participate in the formation of the fertilization membrane. The content of organelles that form their secretory apparatus also increases in follicular cells. The transparent shell thickens; microvilli of the oocyte penetrate into it, contacting the processes of follicular cells (see Fig. 25). thickens follicle basement membrane between these cells and the surrounding stroma; the latter forms connective tissue membrane (theca) of the follicle(see Fig. 266).

Tertiary (vesicular, antral) follicles formed from secondary ones due to secretion by follicular cells follicular fluid which first accumulates in small cavities of the follicular membrane, which later merge into a single follicle cavity(antrum). Oocyte is inside oviparous tubercle- accumulations of follicular cells protruding into the lumen of the follicle (see Fig. 266). The remaining follicular cells are called granulosa and produce female sex hormones estrogens, the levels of which in the blood increase as the follicles grow. The theca of the follicle is divided into two layers: outer layer of theca contains fibroblasts theca, in inner layer of theca steroid-producing endocrinocytes theca.

Mature (preovulatory) follicles (Graafian follicles) - large (18-25 mm), protrude above the surface of the ovary.

Ovulation- rupture of a mature follicle with the release of an oocyte from it, as a rule, occurs on the 14th day of a 28-day cycle under the influence of a surge of LH. A few hours before ovulation, the oocyte, surrounded by cells of the egg-bearing tubercle, separates from the wall of the follicle and floats freely in its cavity. In this case, the follicular cells associated with the transparent membrane elongate, forming the so-called radiant crown. In the primary oocyte, meiosis (blocked in prophase of division I) is resumed with the formation secondary oocyte And first polar body. The secondary oocyte then enters the second division of maturation, which is blocked in metaphase. Rupture of the follicle wall and covering

The destruction of the ovarian tissue occurs in a small thinned and loosened protruding area - stigma. In this case, an oocyte surrounded by cells of the corona radiata and follicular fluid are released from the follicle.

Corpus luteum is formed as a result of differentiation of granulosa and theca cells of the ovulated follicle, the walls of which collapse, forming folds, and in the lumen there is a blood clot, which is later replaced by connective tissue (see Fig. 265).

Development of the corpus luteum (luteogenesis) includes 4 stages: 1) proliferation and vascularization; 2) ferruginous metamorphosis; 3) flourishing and 4) reverse development.

Stage of proliferation and vascularization characterized by active proliferation of granulosa and theca cells. Capillaries grow into the granulosa from the inner layer of the theca, and the basement membrane separating them is destroyed.

Stage of ferruginous metamorphosis: granulosa and theca cells turn into polygonal light-colored cells - luteocytes (granulosa) And techies), in which a powerful synthetic apparatus is formed. The bulk of the corpus luteum consists of large light granulosa luteocytes, along its periphery lie small and dark luteocytes theca(Fig. 267).

Blooming stage characterized by the active function of luteocytes producing progesterone- female sex hormone that promotes the occurrence and progression of pregnancy. These cells contain large lipid droplets and are in contact with an extensive capillary network

(Fig. 268).

Reverse development stage includes a sequence of degenerative changes in luteocytes with their destruction (luteolytic body) and replacement with a dense connective tissue scar - whitish body(see Fig. 265).

Follicular atresia- a process involving growth arrest and destruction of follicles, which, affecting small follicles (primordial, primary), leads to their complete destruction and complete replacement with connective tissue, and when developing in large follicles (secondary and tertiary) causes their transformation with the formation atretic follicles. With atresia, the oocyte (only its transparent shell is preserved) and granulosa cells die, while the cells of the theca interna, on the contrary, grow (Fig. 269). For some time, the atretic follicle actively synthesizes steroid hormones,

is subsequently destroyed, replaced by connective tissue - a whitish body (see Fig. 265).

All described sequential changes in the follicles and corpus luteum, occurring cyclically during the reproductive period of a woman’s life and accompanied by corresponding fluctuations in the levels of sex hormones, are called ovarian cycle.

Chyle cells form clusters around capillaries and nerve fibers in the area of the ovarian hilum (see Fig. 264). They are similar to interstitial endocrinocytes (Leydig cells) of the testicle, contain lipid droplets, a well-developed agranular endoplasmic reticulum, and sometimes small crystals; produce androgens.

Oviduct

The fallopian tubes are muscular tubular organs that stretch along the broad ligament of the uterus from the ovary to the uterus.

Functions fallopian tubes: (1) capture of the oocyte released from the ovary during ovulation and its transfer towards the uterus; (2) creating conditions for the transport of sperm from the uterus; (3) providing the environment necessary for fertilization and initial development of the embryo; (5) transfer of the embryo into the uterus.

Anatomically, the fallopian tube is divided into 4 sections: a funnel with a fringe that opens in the ovary region, an expanded part - the ampulla, a narrow part - the isthmus and a short intramural (interstitial) segment located in the wall of the uterus. The wall of the fallopian tube consists of three membranes: mucous membrane, muscle And serous(Fig. 270 and 271).

Mucous membrane forms numerous branching folds, strongly developed in the infundibulum and ampulla, where they almost completely fill the lumen of the organ. In the isthmus these folds are shortened, and in the interstitial segment they turn into short ridges (see Fig. 270).

Epithelium mucous membrane - single-layer columnar, formed by two types of cells - ciliated And secretory. Lymphocytes are constantly present in it.

Own record mucous membrane - thin, formed by loose fibrous connective tissue; the fimbria contains large veins.

Muscularis thickens from the ampulla to the intramural segment; consists of vaguely demarcated thick internal circular

and thin outer longitudinal layers(see Fig. 270 and 271). Its contractile activity is enhanced by estrogens and inhibited by progesterone.

Serosa characterized by the presence under the mesothelium of a thick layer of connective tissue containing blood vessels and nerves (subserosal base), and in the ampullar region - bundles of smooth muscle tissue.

Uterus

Uterus is a hollow organ with a thick muscular wall in which the development of the embryo and fetus occurs. The fallopian tubes open into its expanded upper part (body), the narrowed lower (Cervix) protrudes into the vagina, communicating with it through the cervical canal. The wall of the uterine body consists of three membranes (Fig. 272): 1) mucous membrane (endometrium), 2) muscular layer (myometrium) and 3) serous membrane (perimetry).

Endometrium undergoes cyclic changes during the reproductive period (menstrual cycle) in response to rhythmic changes in hormone secretion by the ovary (ovarian cycle). Each cycle ends with the destruction and removal of part of the endometrium, which is accompanied by the release of blood (menstrual bleeding).

The endometrium consists of a covering single layer columnar epithelium, who is educated secretory And ciliated epithelial cells, And own record- endometrial stroma. The latter contains simple tubular uterine glands, which open onto the surface of the endometrium (Fig. 272). The glands are formed by columnar epithelium (similar to the integumentary epithelium): their functional activity and morphological features change significantly during the menstrual cycle. The endometrial stroma contains fibroblast-like cells (capable of a number of transformations), lymphocytes, histiocytes and mast cells. Between the cells there is a network of collagen and reticular fibers; elastic fibers are found only in the arterial wall. The endometrium has two layers that differ in structure and function: 1) basal and 2) functional(see Fig. 272 and 273).

Basal layer the endometrium is attached to the myometrium, contains the bottoms of the uterine glands, surrounded by dense stroma cellular elements. It is little sensitive to hormones, has a stable structure and serves as a source of restoration of the functional layer.

Receives nutrition from straight arteries, departing from radial arteries, which penetrate the endometrium from the myometrium. It contains the proximal parts spiral arteries, serving as a continuation of the radial ones into the functional layer.

Functional layer (at its full development) much thicker than the basal one; contains numerous glands and vessels. It is highly sensitive to hormones, under the influence of which its structure and function change; at the end of each menstrual cycle (see below), this layer is destroyed, restored again in the next. Supplied with blood from spiral arteries, which are divided into a number of arterioles associated with capillary networks.

Myometrium- the thickest lining of the uterine wall - includes three vaguely demarcated muscle layers: 1) submucosal- internal, with an oblique arrangement of bundles of smooth muscle cells; 2) vascular- medium, the widest, with a circular or spiral course of bundles of smooth muscle cells, containing large vessels; 3) supravascular- external, with an oblique or longitudinal arrangement of bundles of smooth muscle cells (see Fig. 272). Between the bundles of smooth myocytes there are layers of connective tissue. The structure and function of the myometrium depend on female sex hormones estrogen, enhancing its growth and contractile activity, which is inhibited progesterone. During childbirth, the contractile activity of the myometrium is stimulated by the hypothalamic neurohormone oxytocin.

Perimetry has a typical structure of the serous membrane (mesothelium with underlying connective tissue); it does not completely cover the uterus - in those areas where it is absent, there is an adventitial membrane. The perimetry contains sympathetic nerve ganglia and plexuses.

Menstrual cycle- natural changes in the endometrium, which repeat on average every 28 days and are conditionally divided into three phases: (1) menstrual(bleeding), (2) proliferation,(3) secretion(see Fig. 272 and 273).

Menstrual phase (days 1-4) in the first two days is characterized by the removal of the destroyed functional layer (formed in the previous cycle) along with a small amount of blood, after which only basal layer. The surface of the endometrium, not covered with epithelium, undergoes epithelialization in the next two days due to the migration of the epithelium from the bottoms of the glands to the surface of the stroma.

Proliferation phase (5-14th days of the cycle) is characterized by increased growth of the endometrium (under the influence estrogen, secreted by the growing follicle) with the formation of structurally formed, but functionally inactive narrow uterine glands, towards the end of the phase, acquiring a corkscrew-like motion. There is active mitotic division of endometrial gland and stroma cells. Formation and growth takes place spiral arteries, few convoluted in this phase.

Secretion phase (15-28th days of the cycle) and is characterized by active activity of the uterine glands, as well as changes in stromal elements and blood vessels under the influence progesterone, secreted by the corpus luteum. In the middle of the phase, the endometrium reaches its maximum development, its condition is optimal for embryo implantation; at the end of the phase, the functional layer undergoes necrosis due to vasospasm. The production and secretion of secretions by the uterine glands begins on the 19th day and intensifies by the 20-22nd. The glands have a convoluted appearance, their lumen is often saccularly stretched and filled with secretion containing glycogen and glycosaminoglycans. The stroma swells, and islands of large polygonal structures form in it. predecidual cells. Due to intensive growth, the spiral arteries become sharply tortuous, twisting in the form of balls. In the absence of pregnancy due to regression of the corpus luteum and a decrease in progesterone levels on days 23-24, the secretion of endometrial glands ends, its trophism worsens and degenerative changes. The swelling of the stroma decreases, the uterine glands become folded, saw-toothed, and many of their cells die. The spiral arteries spasm on the 27th day, stopping the blood supply to the functional layer and causing its death. The necrotic and blood-soaked endometrium is rejected, which is facilitated by periodic contractions of the uterus.

Cervix has the structure of a thick-walled tube; it is permeated cervical canal, which begins in the uterine cavity internal throat and ends in the vaginal part of the cervix external pharynx.

Mucous membrane The cervix is formed by epithelium and the lamina propria and differs in structure from the similar lining of the uterine body. Cervical canal characterized by numerous longitudinal and transverse branching palm-shaped folds of the mucous membrane. It's lined single-layer columnar epithelium, which protrudes into its own plate, forming

about 100 branched cervical glands(Fig. 274).

Epithelium of the canal and glands includes two types of cells: numerically predominant glandular mucous cells (mucocytes) And ciliated epithelial cells. Changes in the mucous membrane of the cervix during the menstrual cycle are manifested by fluctuations in the secretory activity of cervical mucocytes, which increases approximately 10 times in the middle of the cycle. The cervical canal is normally filled with mucus (cervical plug).

Epithelium of the vaginal part of the cervix,

as in the vagina, - multilayer flat non-keratinizing, containing three layers: basal, intermediate and superficial. The border of this epithelium with the epithelium of the cervical canal is sharp, passes mainly above the external pharynx (see Fig. 274), but its location is not constant and depends on endocrine influences.

Own record The mucous membrane of the cervix is formed by loose fibrous connective tissue with a high content of plasma cells that produce secretory IgA, which are transferred into the mucus by epithelial cells and ensure the maintenance of local immunity in the female reproductive system.

Myometrium consists predominantly of circular bundles of smooth muscle cells; the content of connective tissue in it is much higher (especially in the vaginal part) than in the myometrium of the body, the network of elastic fibers is more developed.

Placenta

Placenta- a temporary organ formed in the uterus during pregnancy and providing a connection between the organisms of the mother and the fetus, thanks to which the growth and development of the latter occurs.

Functions of the placenta: (1) trophic- providing nutrition to the fetus; (2) respiratory- ensuring fetal gas exchange; (3) excretory(excretory) - removal of fetal metabolic products; (4) barrier- protection of the fetal body from the effects of toxic factors, preventing microorganisms from entering the fetal body; (5) endocrine- synthesis of hormones that ensure the course of pregnancy and prepare the mother’s body for childbirth; (6) immune- ensuring immune compatibility of mother and fetus. It is customary to distinguish maternal And fetal part placenta.

Chorionic plate located under the amniotic membrane; she was educated in

fibrous connective tissue that contains chorionic vessels- branches of the umbilical arteries and umbilical vein (Fig. 275). The chorionic plate is covered with a layer fibrinoid- a homogeneous structureless oxyphilic substance of glycoprotein nature, which is formed by the tissues of the maternal and fetal organism and covers various parts of the placenta.

Chorionic villi originate from the chorionic plate. Large villi branch strongly, forming a villous tree that is immersed in intervillous spaces (lacunae), filled with maternal blood. Among the branches of the villous tree, depending on the caliber, position in this tree and function, several types of villi are distinguished (large, intermediate and terminal). Large ones, in particular stem (anchor) villi perform a supporting function, contain large branches of the umbilical vessels and regulate the flow of fetal blood into the capillaries of small villi. Anchor villi are connected to the decidua (basal plate) cell columns, formed by extravillous cytotrophoblast. Terminal villi move away from intermediate and are an area of active exchange between the blood of the mother and the fetus. The components that form them remain unchanged, but the relationship between them undergoes significant changes at different stages of pregnancy (Fig. 276).

Villous stroma formed by loose fibrous connective tissue containing fibroblasts, mast and plasma cells, as well as special macrophages (Hoffbauer cells) and fetal blood capillaries.

Trophoblast covers the villi from the outside and is represented by two layers - the outer layer syncytiotrophoblastoma and internal - cytotrophoblast.

Cytotrophoblast- a layer of mononuclear cubic cells (Langhans cells) - with large euchromatic nuclei and weakly or moderately basophilic cytoplasm. They maintain their high proliferative activity throughout pregnancy.

Syncytiotrophoblast is formed as a result of the fusion of cytotrophoblast cells, therefore it is represented by extensive cytoplasm of variable thickness with well-developed organelles and numerous microvilli on the apical surface, as well as numerous nuclei that are smaller than in the cytotrophoblast.

Villi in early pregnancy covered with a continuous layer of cytotrophoblast and a broad layer of syncytiotrophoblast with evenly distributed nuclei. Their voluminous, loose stroma of the immature type contains individual macrophages and a small number of poorly developed capillaries, located mainly in the center of the villi (see Fig. 276).

Villi in the mature placenta characterized by changes in the stroma, blood vessels and trophoblast. The stroma becomes looser, macrophages are rare in it, capillaries have a sharply convoluted course, and are located closer to the periphery of the villi; at the end of pregnancy, so-called sinusoids appear - sharply dilated segments of capillaries (in contrast to the sinusoids of the liver and bone marrow covered with a continuous endothelial lining). The relative content of cytotrophoblast cells in the villi decreases in the second half of pregnancy, and their layer loses its continuity, and by the time of birth only individual cells remain in it. The syncytiotrophoblast becomes thinner, in some places forming thinned areas close to the endothelium of the capillaries. Its nuclei are reduced, often hyperchromatic, form compact clusters (nodes), undergo apoptosis and, together with fragments of the cytoplasm, are separated into the maternal bloodstream. The trophoblast layer is covered from the outside and is replaced by fibrinoid (see Fig. 276).

Placental barrier- a set of tissues that separate the maternal and fetal blood flow, through which two-way exchange of substances occurs between the mother and the fetus. In the early stages of pregnancy, the thickness of the placental barrier is maximum and is represented by the following layers: fibrinoid, syncytiotrophoblast, cytotrophoblast, basement membrane of the cytotrophoblast, connective tissue of the villus stroma, basement membrane of the villus capillary, its endothelium. The thickness of the barrier decreases significantly towards the end of pregnancy due to the tissue changes noted above (see Fig. 276).

Maternal part of the placenta educated basal lamina of the endometrium (basal decidua), from which to intervillous spaces connective tissue septa depart (septa), not reaching the chorionic plate and not completely delimiting this space into separate chambers. The decidua contains special decidual cells, which are formed during pregnancy from predecidual cells appearing in the stroma

endometrium in the secretory phase of each menstrual cycle. Decidual cells are large, oval or polygonal in shape, with a round, eccentrically located light nucleus and acidophilic vacuolated cytoplasm containing a developed synthetic apparatus. These cells secrete a number of cytokines, growth factors and hormones (prolactin, estradiol, corticoliberin, relaxin), which, on the one hand, collectively limit the depth of trophoblast invasion into the uterine wall, and on the other, provide local tolerance immune system mother in relation to the allogeneic fetus, which determines the successful course of pregnancy.

Vagina

Vagina- a thick-walled, extensible tubular organ that connects the vestibule of the vagina to the cervix. The vaginal wall consists of three membranes: mucous membrane, muscle And adventitial.

Mucous membrane lined with thick multilayered squamous non-keratinizing epithelium lying on the lamina propria (see Fig. 274). Epithelium includes basal, intermediate And surface layers. It constantly contains lymphocytes, antigen-presenting cells (Langerhans). The lamina propria consists of fibrous connective tissue with a large number of collagen and elastic fibers and an extensive venous plexus.

Muscularis consists of bundles of smooth muscle cells forming two poorly demarcated layers: internal circular And external longitudinal, which continue into similar layers of the myometrium.

Adventitia formed by connective tissue that merges with the adventitia of the rectum and Bladder. Contains a large venous plexus and nerves.

Breast

Breast is part of the reproductive system; its structure varies significantly depending on different periods life, which is due to differences in hormonal levels. U adult woman The mammary gland consists of 15-20 shares- tubular-alveolar glands, which are delimited by strands of dense connective tissue and, diverging radially from the nipple, are further divided into multiple lobules. There is a lot of fat between the lobules

fabrics. The lobes on the nipple open milk ducts, extended areas of which (milky sinuses) located under areola(pigmented areola). The milky sinuses are lined with stratified squamous epithelium, the remaining ducts are lined with single-layer cubic or columnar epithelium and myoepithelial cells. The nipple and areola contain a large amount sebaceous glands, as well as bundles of radial (longitudinal) smooth muscle cells.

Functionally inactive mammary gland

contains a poorly developed glandular component, which consists mainly of ducts. End sections (alveoli) are not formed and have the appearance of terminal buds. Most of the organ is occupied by stroma, represented by fibrous connective and adipose tissue (Fig. 277). During pregnancy, under the influence of high concentrations of hormones (estrogens and progesterone in combination with prolactin and placental lactogen), a structural and functional restructuring of the gland occurs. It includes a sharp proliferation of epithelial tissue with elongation and branching of ducts, the formation of alveoli with a decrease in the volume of adipose and fibrous connective tissue.

Functionally active (lactating) mammary gland formed by lobules consisting of terminal sections (alveoli), filled with milk

com, and intralobular ducts; between the lobules in layers of connective tissue (interlobular septa) interlobular ducts are located (Fig. 278). Secretory cells (galactocytes) contain a developed granular endoplasmic reticulum, a moderate number of mitochondria, lysosomes, and a large Golgi complex (see Fig. 44). They produce products that are secreted various mechanisms. Protein (casein), and milk sugar (lactose) stand out merocrine mechanism by fusion of the secretory membrane protein granules with plasmalemma. Small lipid droplets merge to form larger ones lipid drops, which are directed to the apical part of the cell and secreted into the lumen of the terminal section along with the surrounding areas of the cytoplasm (apocrine secretion)- see fig. 43 and 279.

Milk production is regulated by estrogens, progesterone and prolactin in combination with insulin, corticosteroids, growth hormone and thyroid hormones. Milk release is ensured myoepithelial cells, which with their processes cover galactocytes and contract under the influence of oxytocin. In the lactating mammary gland, the connective tissue has the form of thin partitions infiltrated with lymphocytes, macrophages, and plasma cells. The latter produce class A immunoglobulins, which are transported into the secretion.

ORGANS OF THE FEMALE GENITAL SYSTEM

Rice. 264. Ovary (general view)

Staining: hematoxylin-eosin

1 - surface epithelium (mesothelium); 2 - tunica albuginea; 3 - cortical substance: 3.1 - primordial follicles, 3.2 - primary follicle, 3.3 - secondary follicle, 3.4 - tertiary follicle (early antral), 3.5 - tertiary (mature preovulatory) follicle - Graafian vesicle, 3.6 - atretic follicle, 3.7 - corpus luteum , 3.8 - stroma of the cortex; 4 - medulla: 4.1 - loose fibrous connective tissue, 4.2 - chyle cells, 4.3 - blood vessels

Rice. 265. Ovary. Dynamics of transformation structural components- ovarian cycle (diagram)

The diagram shows the progress of transformations in processes oogenesis And folliculogenesis(red arrows), education and development of the corpus luteum(yellow arrows) and follicular atresia(black arrows). The final stage of transformation of the corpus luteum and atretic follicle is the whitish body (formed by scar connective tissue)

Rice. 266. Ovary. Cortical area

Staining: hematoxylin-eosin

1 - surface epithelium (mesothelium); 2 - tunica albuginea; 3 - primordial follicles:

3.1 - primary oocyte, 3.2 - follicular cells (flat); 4 - primary follicle: 4.1 - primary oocyte, 4.2 - follicular cells (cubic, columnar); 5 - secondary follicle: 5.1 - primary oocyte, 5.2 - transparent membrane, 5.3 - follicular cells (multilayered membrane) - granulosa; 6 - tertiary follicle (early antral): 6.1 - primary oocyte, 6.2 - transparent membrane, 6.3 - follicular cells - granulosa, 6.4 - cavities containing follicular fluid, 6.5 - follicular theca; 7 - mature tertiary (preovulatory) follicle - Graafian vesicle: 7.1 - primary oocyte,

7.2 - transparent membrane, 7.3 - egg-bearing tubercle, 7.4 - follicular cells of the follicle wall - granulosa, 7.5 - cavity containing follicular fluid, 7.6 - the theca of the follicle, 7.6.1 - inner layer of the theca, 7.6.2 - outer layer of the theca; 8 - atretic follicle: 8.1 - remains of the oocyte and transparent membrane, 8.2 - cells of the atretic follicle; 9 - loose fibrous connective tissue (ovarian stroma)

Rice. 267. Ovary. Corpus luteum in its prime

Staining: hematoxylin-eosin

1 - luteocytes: 1.1 - granulosa luteocytes, 1.2 - theca luteocytes; 2 - area of hemorrhage; 3 - layers of loose fibrous connective tissue; 4 - blood capillaries; 5 - connective tissue capsule (ovarian stroma compaction)

Rice. 268. Ovary. Corpus luteum area

Staining: hematoxylin-eosin

1 - granulosa luteocytes: 1.1 - lipid inclusions in the cytoplasm; 2 - blood capillaries

Rice. 269. Ovary. Atretic follicle

Staining: hematoxylin-eosin

1 - remains of a destroyed oocyte; 2 - remains of a transparent shell; 3 - glandular cells; 4 - blood capillary; 5 - connective tissue capsule (ovarian stroma compaction)

Rice. 270. Fallopian tube (general view)

I - ampullary part; II - isthmus Staining: hematoxylin-eosin

1 - mucous membrane: 1.1 - single-layer columnar ciliated epithelium, 1.2 - lamina propria; 2 - muscular layer: 2.1 - inner circular layer, 2.2 - outer longitudinal layer; 3 - serous membrane: 3.1 - loose fibrous connective tissue, 3.2 - blood vessels, 3.3 - mesothelium

Rice. 271. Fallopian tube (wall section)

Staining: hematoxylin-eosin

A - primary folds of the mucous membrane; B - secondary folds of the mucous membrane

1 - mucous membrane: 1.1 - single-layer columnar ciliated epithelium, 1.2 - lamina propria; 2 - muscular layer: 2.1 - inner circular layer, 2.2 - outer longitudinal layer; 3 - serous membrane

Rice. 272. Uterus in various phases of the menstrual cycle

1 - mucous membrane (endometrium): 1.1 - basal layer, 1.1.1 - lamina propria of the mucous membrane (endometrial stroma), 1.1.2 - bottoms of the uterine glands, 1.2 - functional layer, 1.2.1 - single-layer columnar integumentary epithelium, 1.2. 2 - lamina propria (endometrial stroma), 1.2.3 - uterine glands, 1.2.4 - secretion of the uterine glands, 1.2.5 - spiral artery; 2 - muscular layer (myometrium): 2.1 - submucosal muscular layer, 2.2 - vascular muscular layer, 2.2.1 - blood vessels (arteries and veins), 2.3 - supravascular muscular layer; 3 - serous membrane (perimetry): 3.1 - loose fibrous connective tissue, 3.2 - blood vessels, 3.3 - mesothelium

Rice. 273. Endometrium in various phases of the menstrual cycle

Staining: CHIC reaction and hematoxylin

A - proliferation phase; B - secretion phase; B - menstrual phase

1 - basal layer of the endometrium: 1.1 - lamina propria of the mucous membrane (endometrial stroma), 1.2 - bottoms of the uterine glands, 2 - functional layer of the endometrium, 2.1 - single-layer columnar integumentary epithelium, 2.2 - lamina propria (endometrial stroma), 2.3 - uterine glands, 2.4 - secretion of the uterine glands, 2.5 - spiral artery

Rice. 274. Cervix

Staining: CHIC reaction and hematoxylin

A - palm-shaped folds; B - cervical canal: B1 - external os, B2 - internal os; B - vaginal part of the cervix; G - vagina

1 - mucous membrane: 1.1 - epithelium, 1.1.1 - single-layer columnar glandular epithelium of the cervical canal, 1.1.2 - stratified squamous non-keratinizing epithelium of the vaginal part of the cervix, 1.2 - lamina propria of the mucous membrane, 1.2.1 - cervical glands; 2 - muscular layer; 3 - adventitia

The area of the “junction” of multilayered squamous non-keratinizing and single-layered columnar glandular epithelium is shown by thick arrows

Rice. 275. Placenta (general view)

Staining: hematoxylin-eosin Combined drawing

1 - amniotic membrane: 1.1 - amnion epithelium, 1.2 - amnion connective tissue; 2 - amniochorial space; 3 - fetal part: 3.1 - chorionic plate, 3.1.1 - blood vessels, 3.1.2 - connective tissue, 3.1.3 - fibrinoid, 3.2 - stem (“anchor”) chorionic villi,

3.2.1 - connective tissue (villus stroma), 3.2.2 - blood vessels, 3.2.3 - cytotrophoblast columns (peripheral cytotrophoblast), 3.3 - terminal villus, 3.3.1 - blood capillary,

3.3.2 - fetal blood; 4 - maternal part: 4.1 - decidua, 4.1.1 - loose fibrous connective tissue, 4.1.2 - decidual cells, 4.2 - connective tissue septa, 4.3 - intervillous spaces (lacunae), 4.4 - maternal blood

Rice. 276. Terminal villi of the placenta

A - early placenta; B - late (mature) placenta Staining: hematoxylin-eosin

1 - trophoblast: 1.1 - syncytiotrophoblast, 1.2 - cytotrophoblast; 2 - embryonic connective tissue of the villi; 3 - blood capillary; 4 - fetal blood; 5 - fibrinoid; 6 - mother's blood; 7 - placental barrier

Rice. 277. Mammary gland (non-lactating)

Staining: hematoxylin-eosin

1 - terminal buds (unformed terminal sections); 2 - excretory ducts; 3 - connective tissue stroma; 4 - adipose tissue

Rice. 278. Mammary gland (lactating)

Staining: hematoxylin-eosin

1 - lobule of the gland, 1.1 - terminal sections (alveoli), 1.2 - intralobular duct; 2 - interlobular connective tissue layers: 2.1 - interlobular excretory duct, 2.2 - blood vessels

Rice. 279. Mammary gland (lactating). Lobule area

Staining: hematoxylin-eosin

1 - terminal section (alveolus): 1.1 - basement membrane, 1.2 - secretory cells (galactocytes), 1.2.1 - lipid droplets in the cytoplasm, 1.2.2 - release of lipids by the mechanism of apocrine secretion, 1.3 - myoepitheliocytes; 2 - layers of loose fibrous connective tissue: 2.1 - blood vessel

Myometrium consists of three layers of smooth muscle tissue, between which are layers of loose connective tissue. Due to the absence of a submucosa, the myometrium is immovably connected to the basal layer of the lamina propria of the uterine mucosa. The inner muscular layer, located under the mucous membrane, consists of obliquely oriented bundles of smooth myocytes; in the middle layer they have a circular direction, and in the outer subserous layer they also have an oblique longitudinal direction, opposite to the direction in the inner layer. There are no sharp boundaries between the layers of muscle tissue. Large blood vessels are located here. When the uterus contracts, the vessels are pinched, which prevents bleeding during menstruation and childbirth. Estrogens increase the electrical excitability of smooth muscle cells, and progesterone, on the contrary, increases the excitability threshold of these cells.

Perimetry- the serous membrane of the uterus, covers a significant part of the organ, with the exception of the anterior and lateral surfaces of the supravaginal region. Mesothelium and loose fibrous connective tissue participate in the formation of perimetry.

Cervix represents the lower narrowed part and has the appearance of a muscular cylinder. In the center of the cervix passes the cervical, or cervical, canal, which begins in the cavity of the uterine body with the internal os. The distal part of the cervix protrudes into the vagina and ends at the external os. The cervix consists of the same membranes as the body. The cervical canal is lined with single-layer prismatic epithelium, which in the area of the distal (vaginal) part of the cervix is connected to multilayered squamous non-keratinizing epithelium. The latter continues into the epithelium of the vaginal mucosa. The border between multilayer and single-layer prismatic epithelium of the mucous membrane is always clear and is approximately located at the level of the distal part of the cervix.

The fallopian tubes

Fallopian tube (oviduct)- a paired tubular organ, the distal end of which, shaped like a funnel, is open and in contact with the surface of the ovary, and the proximal end pierces the wall of the uterus in the area of the lateral surfaces of its bottom and communicates the tubes with the uterine cavity. In humans, the length of the fallopian tubes is about 10-12 cm. The fallopian tubes capture the oocyte during ovulation, transport it towards the uterine cavity, create conditions for the unhindered movement of sperm towards the oocyte, provide the environment necessary for fertilization and fragmentation of the embryo, transport the embryo to uterine cavity. The fallopian tubes develop from the upper part of the paramesonephric (Müllerian) ducts.

Oviduct is divided into 4 sections: the infundibulum - the distal section of the tube, ending with fimbriae (fimbriae) and opening into the ovarian bursa, the ampulla - the widest and longest part following the infundibulum (about 2/3 of the length of the tube), the isthmus, or isthmus, and the interstitial ( intramural) section that pierces the wall of the uterus.

Fallopian tube wall consists of three membranes: mucous, muscular and serous.

Mucous membrane consists of a single-layer prismatic epithelium of the coelomic type and the lamina propria. The epithelium is formed by two types of cells - ciliated and secretory. Along the fallopian tube, ciliated and secretory epithelial cells are located unevenly ciliated, predominating in the infundibulum and ampulla of the tube, and secretory epithelial cells in the isthmus region. Secretory epithelial cells of the fallopian tubes are characterized by apo- and merocrine types of secretion. The main components of the secretion are prealbumin, transferrin, globulin and lipoproteins, as well as glycosaminoglycans, prostaglandins, uteroglobin.

Own record tubal mucosa thin and formed by loose fibrous connective tissue. In addition to the types of cells typical for this tissue, cells capable of decidual transformation are found in its composition.

Muscular lining of the fallopian tubes formed by two vaguely demarcated layers of smooth muscle tissue - the inner circular (thicker) and the outer longitudinal (thinner). The thickness of the muscular layer increases from the infundibulum to the isthmus. In the area of the isthmus, the inner circular layer forms the circular muscle of the fallopian tube. If the embryo is implanted into the wall of the pipe, the latter is easily injured and ruptured.
Serosa represented by mesothelium and connective tissue.

Lecture 29: Female reproductive system.

1. Sources, formation and development of the organs of the female reproductive system.

2. Histological structure, histophysiology of the ovaries.

3. Histological structure of the uterus and oviducts.

4. Histological structure, regulation of mammary gland functions.

I.Embryonic development of the organs of the female reproductive system. The organs of the female reproductive system develop from the following sources:

a) coelomic epithelium covering the first kidney (splanchnotomes) ® follicular cells of the ovaries;

b) endoderm of the yolk sac ® oocytes;

c) mesenchyme ® connective tissue and smooth muscles of organs, interstitial cells of the ovaries;

d) paramesonephric (Müllerian) duct ® epithelium of the fallopian tubes, uterus and parts of the vagina.

The formation and development of the reproductive system is closely connected with the urinary system, namely with the first kidney. The initial stage of the formation and development of organs of the reproductive system in females and males proceeds in the same way and is therefore called the indifferent stage. At the 4th week of embryogenesis, the coelomic epithelium (visceral layer of splanchnotomes) on the surface of the first kidney thickens - these thickenings of the epithelium are called genital ridges. Primary germ cells, gonoblasts, begin to migrate into the genital ridges. Gonoblasts first appear as part of the extraembryonic endoderm of the yolk sac, then they migrate to the wall of the hindgut, and there they enter the bloodstream and reach and penetrate into the genital ridges through the blood. Subsequently, the epithelium of the genital ridges, together with gonoblasts, begins to grow into the underlying mesenchyme in the form of cords - they are formed sex cords. The reproductive cords consist of epithelial cells and gonoblasts. Initially, the sex cords retain contact with the coelomic epithelium, and then break away from it. Around the same time, the mesonephric (Wolffian) duct (see embryogenesis of the urinary system) splits and the paramesanephric (Müllerian) duct is formed parallel to it, which also flows into the cloaca. This is where the indifferent stage of development of the reproductive system ends.

As the mesenchyme grows, it divides the sex cords into separate fragments or segments - the so-called egg balls. In the oviparous balls, gonocytes are located in the center, surrounded by epithelial cells. In the egg-bearing balls, gonocytes enter the first stage of oogenesis - the stage of reproduction: they begin to divide by mitosis and turn into Oogonia, and the surrounding epithelial cells begin to differentiate into follicular cells. The mesenchyme continues to crush the egg-bearing balls into even smaller fragments until 1 germ cell remains in the center of each fragment, surrounded by 1 layer of flat follicular cells, i.e. premordial follicle. In premordial follicles, oogonia enter the growth stage and transform into oocytesIorder. Soon the growth of first order oocytes in the premordial follicles stops and subsequently the premordial follicles remain unchanged until puberty. The combination of premordial follicles with layers of loose connective tissue between them forms the ovarian cortex. The surrounding mesenchyme forms a capsule, connective tissue layers between the follicles and interstitial cells in the cortex and connective tissue of the medulla of the ovaries. From the remaining part of the coelomic epithelium of the genital ridges, the outer epithelial cover of the ovaries is formed.

II. Histological structure and histophysiology of the ovaries. On the surface, the organ is covered with mesothelium and a capsule of dense, unformed fibrous connective tissue. Under the capsule is the cortex, and in the central part of the organ is the medulla. The ovarian cortex of a mature woman contains follicles at different stages of development, atretic bodies, corpus luteum, corpus alba and layers of loose connective tissue with blood vessels between the listed structures.

1. The first order oocyte enters the phase of large growth, increases in size approximately 2 times and acquires secondary – zona pellucida(both the egg itself and follicular cells are involved in its formation); the surrounding follicular ones transform from a single-layer flat first to a single-layer cubic, and then to a single-layer cylindrical. This follicle is called Ifollicle.

2. Follicular cells multiply and from a single-layer cylindrical become multi-layered and begin to produce follicular fluid (contains estrogens), which accumulates in the developing cavity of the follicle; An oocyte of the first order, surrounded by I and II (pellucid) membranes and a layer of follicular cells, is pushed to one pole (oviferous tubercle). This follicle is called IIfollicle.

3. The follicle accumulates a lot of follicular fluid in its cavity, therefore it greatly increases in size and protrudes on the surface of the ovary. This follicle is called IIIfollicle(or vesicular or Graafian bubble). As a result of stretching, the thickness of the wall of the third follicle and the covering albuginea of the ovary sharply thins. At this time, the first-order oocyte enters the next stage of oogenesis - the maturation stage: the first meiotic division occurs and the first-order oocyte turns into a second-order oocyte. Next, the thinned wall of the follicle and the tunica albuginea rupture and ovulation occurs - an oocyte of the second order, surrounded by a layer of follicular cells (corona radiata) and membranes I and II, enters the peritoneal cavity and is immediately captured by fimbriae (fimbriae) into the lumen of the fallopian tube.

In the proximal part of the fallopian tube, the second division of the maturation stage quickly occurs and the second-order oocyte turns into a mature egg with a haploid set of chromosomes.

The ovulation process is regulated by the adenohypophysis hormone lutropin.

Yellow body. After ovulation, at the site of the burst follicle, under the influence of the adenohypophysis hormone lutropin, the corpus luteum is formed in several stages:

Stage I – vascularization and proliferation. Blood flows into the cavity of the ruptured follicle, blood vessels grow into the blood clot (hence the word “vascularization” in the name); At the same time, multiplication or proliferation of follicular cells in the wall of the former follicle occurs.

Stage III – dawn. The corpus luteum reaches a large size (diameter up to 2 cm) and progesterone synthesis reaches a maximum.

IV stage – reverse development. If fertilization does not occur and pregnancy does not begin, then 2 weeks after ovulation the corpus luteum (called the menstrual corpus luteum) undergoes reverse development and is replaced by a connective tissue scar - it is formed white body(corpus albicans). If pregnancy occurs, the corpus luteum increases in size to 5 cm in diameter (corpus luteum of pregnancy) and functions during the first half of pregnancy, i.e. 4.5 months.

The hormone progesterone regulates the following processes:

1. Prepares the uterus to receive the embryo (the thickness of the endometrium increases, the number of decidual cells increases, the number and secretory activity of the uterine glands increases, the contractile activity of the uterine muscles decreases).

2. Prevents subsequent premordial ovarian follicles from entering the maturation pathway.

Atretic bodies. Normally, several premordial follicles simultaneously enter the maturation path, but most often 1 follicle matures to the third follicle, the rest undergo reverse development at different stages of development - atresia(under the influence of the hormone gonadocrinin, produced by the largest of the follicles) and in their place are formed atretic bodies. With atresia, the egg dies, leaving behind a deformed, wrinkled zona pellucida in the center of the atretic body; follicular cells also die, but the interstitial cells of the tegmentum multiply and begin to actively function (estrogen synthesis). Biological significance of atretic bodies: prevention of superovulation - the simultaneous maturation of several eggs and, as a consequence, the conception of several fraternal twins; endocrine function - in initial stages development, one growing follicle cannot create the required level of estrogen in the female body, therefore atretic bodies are necessary.

III.Histological structure of the uterus. The uterus is a hollow muscular organ in which the embryo develops. The wall of the uterus consists of 3 membranes - endometrium, myometrium and perimeter.

There are features in the blood supply to the endometrium:

1. Arteries - have a spiral course - this structure of the arteries is important during menstruation:

Spastic contraction of the spiral arteries leads to malnutrition, necrosis and rejection of the functional layer of the endometrium during menstruation;

Such vessels thrombose faster and reduce blood loss during menstruation.

2. Veins - form expansions or sinuses.

Myometrium (muscular membrane) The uterus has 3 layers of smooth muscle:

1. Internal – submucosal layer.

2. Middle – vascular layer.

3. Outer – supravascular layer.

Perimetry– the outer lining of the uterus, represented by connective tissue covered with mesothelium.

Fallopian tubes (oviducts)– have 3 shells:

1. The mucous membrane is lined with a single-layer prismatic ciliated epithelium, beneath it is the lamina propria of the mucous membrane made of loose fibrous connective tissue. The mucosa forms large branched longitudinal folds.

2. Muscular membrane made up of longitudinally and circularly oriented myocytes.

3. The outer shell is serous.

IV.Mammary gland. Since the function and regulation of functions is closely related to the reproductive system, the mammary glands are usually studied in the section on the female reproductive system.

The mammary glands are complex in structure, branched alveolar glands; consist of secretory sections and excretory ducts.

With the onset of lactation, the blind end of these alveolar milk ducts expands, takes the form of vesicles, i.e., turns into alveoli. The alveolar wall is lined with one layer of low-prismatic cells—lactocytes. At the apical end, lactocytes have microvilli; granular and agranular EPS, a lamellar complex and mitochondria, microtubules and microfilaments are well expressed in the cytoplasm. Lactocytes secrete casein, lactose, and fats in an apocrine manner. From the outside, the alveoli are covered by stellate myoepithelial cells, which promote secretion into the ducts.

Regulation of mammary gland functions:

1. Prolactin (adenohypophysis hormone) – enhances milk synthesis by lactocytes.

2. Oxytocin (from the supraoptic paraventricular nuclei of the hypothalamus) - causes the secretion of milk from the gland.

3. Glucocorticoids of the zona fasciculata of the adrenal glands and thyroxine thyroid gland also promote lactation.