FEMALE REPRODUCTIBE SYSTEM PART 1 IN ENGLISH

                                              

                FEMALE REPRODUCTIBE SYSTEM PART 1 IN ENGLISH

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FEMALE REPRODUCTIVE SYSTEM PART 1

Ø  Reproduction-  Reproduction is the process of producing offspring. Human reproduction is a sexual reproduction. Reproductive system includes-

Ø  Male reproductive system 

Ø  Female reproductive system 

FEMALE REPRODUCTIVE SYSTEM

Ø  The organs of the female reproductive system are divided into two groups- 

Ø  Internal organs- ovary, fallopian tubes, uterus and vagina.

Ø  External organs- vulva (pudendum) and mammary glands.

OVARY

Ø  Ovary- The ovaries are the female gonads and paired glands that resemble almonds in size and shape; they are homologous to the testes. The ovaries are situated one on either side of the uterus, descend to the brim of the superior portion of the pelvic cavity during the third month of foetal development

Ø  A series of ligaments holds them in position. The broad ligament of the uterus which is itself part of the parietal peritoneum, attaches to the ovaries by a double-layered fold of peritoneum called the mesovarium. The ovarian ligament anchors the ovaries to the uterus, and the suspensory ligament attaches them to the pelvic wall.

Ø  The outermost layer of ovary is germinal epithelium. It is a layer of simple epithelium  that covers the surface of the ovary. The tunica albuginea is a whitish capsule of dense irregular connective tissue located immediately deep to the germinal epithelium.

Ø  The ovarian cortex is a region just deep to the tunica albuginea. It consists of ovarian follicles surrounded by dense irregular connective tissue that contains collagen fibers and fibroblast-like cells called stromal cells.

Ø   • The ovarian medulla is deep to the ovarian cortex. The border between the cortex and medulla is not clear cut, but the medulla consists of more loosely arranged connective tissue and contains blood vessels, lymphatic vessels, and nerves.

Ø  Ovarian follicles   are in the cortex and consist of oocytes in various stages of development, plus the cells surrounding them. they are called follicular cells and granulosa cells. The surrounding cells nourish the developing oocyte and begin to secrete estrogens as the follicle grows larger.

Ø  A mature (graafian) follicle is a large, fluid-filled follicle that is ready to rupture and expel its secondary oocyte. A corpus luteum  contains the remnants of a mature follicle after ovulation. The corpus luteum produces hormones until it degenerates into fibrous scar tissue called the corpus albicans

OOGENESIS

Ø  The formation of gametes in the ovaries is termed oogenesis .  Oogenesis begins in females before they are even born. Oogenesis starts from the cells known as oogonia. Oogonia are diploid (2n) stem cells ( having 46 chromosomes). Most oognia degenrate inside the ovary but few of them develop into primary oocyte (having 46 chromosomes) each primary oocyte is surrounded by a single layer of flat follicular cells, and the entire structure is called a primordial follicle

Ø  primordial follicles remains inactive till puberty. Starting from puberty, each month A few primordial follicles start to grow, developing into primary follicles under effect of FSH & LH secreated by pituitary. Each primary follicle consists of a primary oocyte that is surrounded in a later stage of development by several layers of cuboidal and low-columnar cells called granulosa cells.

Ø  there is a basement membrane that surrounds the outermost layer of granulosa cells. As the primary follicle grows, it forms a clear glycoprotein layer called the zona pellucida between the primary oocyte and the granulosa cells. Stromal cells surrounding the basement membrane begin to form an organized layer called the theca folliculi

Ø  With continuing maturation, a primary follicle develops into a secondary follicle. In a secondary follicle, the theca differentiates into two layers:

Ø  (1) the theca interna,

Ø   (2) the theca externa

Ø  the granulosa cells begin to secrete follicular fluid, which builds up in a cavity called the antrum in the center of the secondary follicle.

Ø  The innermost layer of granulosa cells becomes firmly attached to the zona pellucida and is now called the corona radiata. The secondary follicle eventually becomes larger, turning into a mature (graafian) follicle

Ø   the diploid primary oocyte completes meiosis I, producing two haploid (n) cells of unequal size (small and big) each with 23 chromosomes. Larger one is called secondary oocyte and smaller one is called first polar body

Ø  The mature (graafian) follicle soon ruptures and releases its secondary oocyte, a process known as ovulation. At ovulation, the secondary oocyte is expelled into the pelvic cavity along with the first polar body and corona radiata. Normally these cells are received into the uterine tube. If fertilization does not occur, the cells degenerate.

FERTILIZATION-

Ø  If sperm are present in the uterine tube and one penetrates the secondary oocyte (fertilization) than,   The secondary oocyte splits into two haploid cells (due to meiosis II) , again of unequal size. The larger cell is the ovum, or mature egg; the smaller one is the second polar body. The nuclei of the sperm cell and the ovum then unite, forming a diploid zygote.

Ø  A sperm cell usually encounters and fertilizes a secondary oocyte in the ampulla of the uterine tube. Fertilization can occur at any time up to about 24 hours after ovulation. The diploid fertilized ovum is now called a zygote and begins to undergo cell divisions while moving toward the uterus. It arrives at the uterus 6 to 7 days after ovulation.

FALLOPIAN TUBES-

Ø  There are two uterine (fallopian) tubes, or oviducts, that starts from uterus and reaches up to ovary.  The tubes, which measure about 10 cm (4 in.) long, lie between the folds of the broad ligaments of the uterus. They provide a route for sperm to reach an ovum and transport secondary oocytes and fertilized ovum to the uterus.

Ø  Fallopian tubes have four main parts. One is The isthmus which is medial, short, narrow, thick-walled portion and is attached to the uterus.

Ø  Second portion is ampulla which is the widest, longest portion of the uterine tube and starts from isthmus.

Ø  Third part is infundibulum which is the funnel-shaped portion of fallopian tubes and is close to the ovaray

Ø  Last portion is fimbriae which are fingerlike projections attached to the infundibulum.

Ø  The uterine tubes are composed of three layers of tissue, these are-

Ø  mucosa, muscularis, and serosa.

Ø  The mucosa consists of epithelium and areolar connective tissue. The epithelium contains ciliated simple columnar cells, which help move a fertilized ovum  within the uterine tube toward the uterus.

Ø  The muscular layer is composed of two types of fibers, an inner, thick, circular ring of smooth muscle and an outer, thin region of longitudinal smooth muscle. Peristaltic contractions of the muscular and the ciliary action of the mucosa help move the oocyte or fertilized ovum toward the uterus.

UTERUS

Ø  The uterus is pear shaped structure and situated between bladder and rectum. In females who have never been pregnant, it is about 7.5 cm long, 5 cm  wide, and 2.5 cm  thick.

Ø  the uterus have three  parts which are-.

Ø  Fundus

Ø  Body and

Ø  cervix

Ø  The body of the uterus projects anteriorly and superiorly over the urinary bladder. This position is called anteflexion position.

Ø  The cervix projects inferiorly and posteriorly and enters the anterior wall of the vagina at nearly a right angle

Ø  The Uterus is supported and held in position by many ligaments such as

Ø  Broad Ligaments- The paired broad ligaments are double folds of peritoneum attaching the uterus to either side of the pelvic cavity.

Ø  Uterosacral Ligaments- The paired uterosacral ligaments, also peritoneal extensions, lie on either side of the rectum and connect the uterus to the sacrum.

Ø  Cardinal Ligaments- The cardinal (lateral cervical) ligaments are located inferior to the bases of the broad ligaments and extend from the pelvic wall to the cervix and vagina.

Ø  Round Ligaments- The round ligaments are bands of fibrous connective tissue between  the layers of the broad ligament. they start from the uterus just inferior to the uterine tubes to a portion of the labia majora of the external genitalia.

Ø  The uterus consists of three layers of tissue:

Ø  Perimetrium,

Ø  Myometrium, and

Ø  Endometrium

Ø  Perimetrium- the perimetrium is part of the visceral peritoneum.  it is composed of simple squamous epithelium and areolar connective tissue. Anteriorly, it covers the urinary bladder and forms a shallow pouch, the vesicouterine pouch . Posteriorly, it covers the rectum and forms a deep pouch between the uterus and rectum, the rectouterine pouch  or pouch of Douglas

Ø  Myometrium- The middle layer of the uterus is the myometrium  which consists of three layers of smooth muscle fibers that are thickest in the fundus and thinnest in the cervix. The thicker middle layer is circular; the inner and outer layers are longitudinal and oblique

Ø  Endometrium- the endometrium is highly vascularized layer and has three components:

Ø  (1) An innermost layer composed of simple columnar epithelium having ciliated and secretory cells.

Ø  (2) An underlying endometrial stroma is a very thick region of lamina propria  and is composed of areolar connective tissue.

Ø  (3) Endometrial (uterine) glands develop as invaginations of the luminal epithelium and extend almost to the myometrium.

Ø  The endometrium is divided into two layers.The stratum functionalis (functional layer) lines the uterine cavity and sloughs off during menstruation. The deeper layer, the stratum basalis (basal layer), is permanent and gives rise to a new stratum functionalis after each menstruation.