Female reproductive system

Female reproductive system is ovum-producing reproductive organ (ovaries), reproductive ways concern it (fallopian tubes, a uterus, a vagina, external genitals), mammary glands.

The greatest complexity of a structure at an ovary. It is a dynamical organ in which there are the constant changes bound to the hormonal status.

Develops from a material of the reproductive platen which is pawned on 4 week of an embryogenesis on a medial surface of kidneys. It is formed by a coelomic epithelium (of a visceral leaf of a splanchnotome) and mesenchymas. It is an indifferent stage of development (without reproductive differences). Specific differences attack to 7-8 week. It is preceded by occurrence in the field of the reproductive platen of primary reproductive cells - gonocytes. They contain a lot of glycogen in a cytoplasma high activity of an alkaline phosphatase. From a wall of a vitelline bag gonocytes on a mesenchyma or with a blood current get to reproductive platens, are built in an epithelial plate. Since this moment development of female and man's reproductive glands differs. The oviparous balls of formation consisting of several ovogoniums, the flat epithelial cells surrounded with one layer are formed. Then mesenchyma bands part these balls on are fineer. The primordial follicles consisting of one reproductive cell, surrounded with one layer of flat follicular epitheliocytes are formed. Are formed cortical and cerebral substance a little bit later.

In the embryonal period in an ovary the period of reproduction of an ovogenesis comes to an end and the stage of growth which is most long (some years) begins. Ovogoniums turn to an ovocyte of the first order. The albugineus cover of an ovary, a connective tissue stroma, intersticial cells are differentiated from a surrounding mesenchyma.

Structure of an ovary of an adult organism during the genesial period.

Functions: endocrine and genesial.

From a surface it is covered mesothelium under which the cover formed by a dense connecting tissue - an albugineus cover settles down. Under it the cortical substance, and in the centre - cerebral lays. The cerebral substance is formed by a quaggy connecting tissue in which are available chemoses the cells producing hormones - androgens. In cortical substance a considerable quantity of vascular, lymphatic vessels and nervous elements. The basis (stroma) of cortical substance is formed by a quaggy connecting tissue. In a stroma in a considerable quantity various follicles, yellow and white bodies at different stages of development settle down. During the genesial period in an ovary there is a growth of an ovocyte of the first order in a follicle. Follicles ripen.

Consecutive stages of development of a follicle: the youngest (them it is a lot of 30 - 400.000) - the primordial follicle formed by an ovocyte of the first order round which one layer of flat follicular epitheliocytes which carry out protective and trophic functions is located. Follicles settle down on periphery.

At different stages of an ontogenesis there is a destruction of female reproductive cells an atresia.

Primary follicles. Reproductive cells it is a little bit more. On periphery of ovocytes of the first order a special cover - shining. Round it one layer of cubic or prismatic follicular epitheliocytes settles down. The transparent (brilliant) cover is formed by glycoproteids. In its formation take part an ovocyte of the first order. In a brilliant cover there are radially located pores into which microvillis of an ovocyte and cytoplasmatic processes of follicular epitheliocytes get.

Secondary follicles. Their formation is already bound to a hormonal background (influence a follicle-stimulating hormone). Under its influence follicular epitheliocytes begin strenuously shares. Round an ovocyte of the first order the multilayered follicular epithelium is formed. Formation of secondary follicles comes in puberty. The follicular epithelium synthesises a follicular liquid which contains estrogens. The cavity - a bubbly follicle which is gradually transformed to a tertiary follicle is formed.

Tertiary follicle. Has the is difficult-arranged wall, contains an ovocyte of the first order.

The wall consists of 2 parts:

• A multilayered follicular epithelium - a granular layer (granulosis). Settles down on well expressed basal membrane (a vitreous membrane Slavic).
• The osculant - woven part - the Theca (tyre cover).

In a mature follicle 2 layers:

• Internal quaggy (a considerable quantity of blood vessels, special is hormonal-active cells - thecocytus (a version intersticial cells), producing estrogens. Are a source of formation of tumours).
• Fibrous layer (dense). Consists of fibers. The follicle cavity is filled by a follicular liquid which contains estrogens (a hormone of the albuminous nature, synthesised by follicular cells. It is responsible for a follicle atresia).

On one of poles there is an oviparous hill on which the ovocyte of the first order surrounded with a radiate crown lays. At formation the luteinizing hormone occurs rupture of a follicle and an exit from a reproductive cell ovary - an ovulation.

The reproductive cell directs in a fallopian tube where there is a division and its maturing. On a place of the burst follicle there is a formation of a yellow body. Its cells produce progesterone.

Distinguish 2 kinds of yellow bodies - a menstrual and yellow body of pregnancy. The menstrual body of the smaller sizes (1-2 sm in diameter while a yellow body of pregnancy of 5-6 sm), its life expectancy is less (5-6 days against several months).

Stages of development of a yellow body

• 1 stage is bound to a proliferation and division thecocytes - vascularization.
• 2 stage of glandular transformation. Cells of a granular layer and thecocytes turn to cells - lutheinocites, producing other hormone. The cytoplasma contains a yellow pigment.
• 3 stage of blossoming. The yellow body reaches the maximum size, as much as possible many produced hormones.
• 4 stage - an involution stage. It is bound to destruction of glandular cells. On their place the soedinitelno-woven cicatrix a white body which resolves in due course is formed. Besides progesterone, cells of a yellow body synthesise estrogens, androgens, Oxytocinum, a relaxin in small amounts.

Progesterone brakes formation a follicle-stimulating hormone and maturing of a new follicle in an ovary, influences on mucous a uterus and a mammary gland. Not all follicles reach 4 stages of development. The destruction of follicles of 1 and 2 stages passes imperceptibly. At destruction of follicles of 3 and 4 stages the atresic follicle is formed. Under influence gonadocrinine in case of a follicle atresia the ovocyte of the first order, and then follicular cells at first perishes. From an ovocyte the transparent cover which merges with a vitreous membrane is formed and is in the centre of an atresic follicle.

Intersticial cells activly proliferate, them the considerable quantity is formed and the atresic body (intersticial gland) is formed. Produce estrogens. The biological sense prevention of the phenomena of a superovulation, is reached a certain background in blood of estrogens before the puberty moment.

All transformations to a follicle are called an ovarian cycle. It occurs under the influence of hormones in 2 phases:

• folliculines phase. Under influence a follicle-stimulating hormone
• lutein phase. Under influence the luteinizing hormone, a luteotropic hormone of Change in ovaries cause changes in other organs of female reproductive system fallopian tubes, a uterus, a vagina, mammary glands

Uterus

In a uterus there is a development and a foetus food. It is a muscular organ. 3 covers - mucous (endometrium), muscular (myometrium), serous (perimetrium). The epithelium of the mucous is differentiated from mesonefral a duct. A connecting tissue, an is smooth-muscular tissue - from a mesenchyma. A Mesothelium from a visceral leaf of a splanchnotome.

The endometrium is formed by a single-layered prismatic epithelium and own plate. In an epithelium 2 kinds of cells: ciliary epitheliocytes and secretory epitheliocytes. Own plate is formed by a quaggy fibrous connecting tissue in it there are numerous uterine glands (numerous, the tubular form, a diverticulum of own plate - cryptas). Their quantity, the sizes, depth, activity of secretion depend on a phase of an ovarian-menstrual cycle.

In endometriums distinguish 2 layers: deep basal (it is formed by deep sites of an endometrium) and functional.

The myometrium is formed by a smooth muscular tissue and consists of 3 layers:

• Submucosal layer of a myometrium (slanting locating)
• Vascular layer (in it large blood vessels settle down) a slantwise-longitudinal direction
• Over-vascular a layer (the slantwise-longitudinal direction opposite to a direction of myocytes of a vascular layer) Structure of a myometrium depends on estrogen (at its disadvantage the atrophy develops). Progesterone causes hypertrophic changes.

Perimetrium. It is formed by 2 tissues: a plate of an is smooth-muscular tissue and a single-layered flat epithelium of coelomic type mesothelium.

female reproductive system is characterised by recurrence of a structure and functions which is defined by hormones.

Changes in ovaries and uterus - an ovarian menstrual cycle. Duration on the average 28 days. All period is sectioned into 3 phases:

• Menstrual (since the first day of a menses)
• Postmenstrual (proliferations)
• Premenstrual (secretions) the Menstrual phase approximately 4 days. During this time there is a desquamation ( destruction) of tissues of a mucosa of a uterus, their tearing away, and then epithelium neogenesis. Tearing away of all functional layer to the deepest sites yes cryptas.

Proliferation - epithelium change, restoration of a functional layer of an endometrium, structural veneering of a uterine gland. There is a restoration of spiral arteries about 5-14 days.

For 14 days there is an ovulation. Under the influence of progesterone there is an augmentation of an endometrium to 7 mm (instead of 1 mm), it becomes hydropic, uterine gland takes a corkscrew-shaped a form. The lumen is overflowed by secretory products, helicoid arteries are extended, twist. After 23-24 days vessels spastic. The ischemia and a hypoxia of tissues develops. They necrotising and all begins at first.

Mammary glands

Mammary glands represent the changed sudoral glands with apocrine type of secretion. The glandular tissue has an ectodermal parentage. The differentiation begins on 4 week. Along a forward part of a trunk longitudinal thickened lines from which are formed glands are formed. The structure before puberty sharply differs.

Mammary glands of adult women consist of 15-20 separate glands which have an is alveolar-tubular structure. Each gland forms a share between which there is a layer of a connecting tissue. Each share consists of separate lobes between which the layers of a connecting tissue rich with fatty cells settle down.

The mammary gland consists of secretory departments (an alveolus silt acinuses) and systems of lead-out ducts.

In non lactating to iron there is a considerable quantity of ducts and very few secretory departments. Till the puberty moment in a mammary gland there are no trailer departments. In lactate to an alveolus mammary gland are numerous. Each of them is formed by glandular cells (cubic lacocytes) and myoepitheliocytes. Lacocytes are produced a secret - milk. It is a water emulsion of triglycerides, Glycerinum, milk albumin, globulins, salts, lactose, macrophages, T and B-lymphocytes, immunoglobulins And (which protect the child from intestinal infections). Fibers are allocated from glandular cells on merocryne to type, and Adepses on the apocrine.

During the final period of pregnancy there is a formation and accumulation of a secret of a colostrum. It differs higher maintenance of fiber, than Adeps. And at milk on the contrary.

Sequence of ducts: alveoluses - alveolar lactiferous courses (in lobes) - intralobular ducts (inlay higher epithelium and myoepitheliocytes) - an interlobular duct (in a layer of a connecting tissue). Near to a papilla they extend and called as milk sine.

Activity lacocytes is defined by Prolactinum. Milk allocation is promoted by myoepitheliocytes. Their activity regulates Oxytocinum.