Human reproductive system (Female)

 

Female Reproductive system-

1)      Ovaries- 

·        They are located in the upper pelvic cavity.

·        They are 2 to 4 cm in length.

·        They are attached to uterus by ovarian ligament.

·        The broad ligament of the uterus which is itself a part of partial peritoneum attaches to the ovary by a double layered fold of peritoneum called mesovarium.

·        Ovaries are covered by a layer of cuboidal epithelium called the geminal epithelium. Geminal epithelium is covered by visceral peritoneum.

·        Beneath the epithelium is the tunica albuginea a layer of connective tissue and underlying it is the ovarian stroma.

·        Ovarian stroma consists of dense outer layer called cortex and a comparative less dense connective tissue called medulla.

·        No more oogonia are formed and added after birth. Oogonia divided by mitosis forming primary oocyte. Each primary oocyte then gets surrounded by a layer of granulosa cells called primary follicles.

·        A large number of there follicle degenerates from birth to puberty. Therefore, at the time of puberty only 60000 to 80000 primary oocytes are left in each ovary. When primary follicle is surrounded by a greater number of granulosa cell then they are called secondary follicle. Secondary follicle soon gets converted into tertiary follicle which is characterised by a fluid filled cavity called follicular antrum. A tertiary follicle further converts into a mature follicle or Graafian follicle.

·        A follicle consists of an oocyte covered by a homogeneous membrane the zona pellucida. When the surrounding cells form a single layer, they are called follicular cells. Later in development when they form several layers they are referred as granulosa cells. Surrounding cell nourishes the developing oocyte and begin to secret oestrogen as the follicle grows larger. Zona pellucida is surrounded by follicular cell called membranous granulosa. The follicle has an eccentric follicular cavity or the follicular fluid. The oocyte adheres to the wall of the follicle through a pedicle the cumulus oophores formed by granulosa cells and thus remain suspended in the follicular cavity.  Later the granulosa cell lying in close vicinity of the oocyte and zona pellucida becomes elongated to form the corona radiata. The membrane granulosa is surrounded by the theca interna and theca externa total number of follicles in two ovary of a normal young adult woman is about four lakhs. Many ovarian follicles undergo degeneration. This degeneration process of follicle is called follicular atresia. And such follicle is known as atretic follicle. Release of secondary oocyte from the ovary is called ovulation. It occurs due to rupturing of graafian follicle and ovarian wall. Generally, one secondary oocyte is released in one menstrual cycle by alternate ovaries. Therefore only 450 secondary oocytes are produced by adult human female through their life. When follicles were developing some follicular cells releases two hormones. Oestrogen and estradiol. After ovulation many follicular cells remain on the surface of ovary. The follicular cells enlarge and fill with a yellow pigment lutein such a follicle is called as corpus leuteum. The leuteal cell secret small amount of estradiol, progesterone and relaxing hormones.

 

2)     Fallopian tubes- (about 10-12cm long)

·        Infundibulum- it is dilated trumpet like portion opening into the peritoneal cavity. End of the tube has a finger like projection called fimbriae which helps in collection of ovum after ovulation.

·        Ampulla- it is the widest and longest part of the fallopian tube.

·        Isthumus- it is the shortest narrow thick-walled portion that follows the ampulla.

·        Uterine part- it passes through the uterine wall and communicates with uterine cavity.

Function of fallopian tube is to convey the ovum from ovary to the uterus. It is done by peristalsis. In fallopian tubes in ampulla, part fertilization takes place.

3)     Uterus-

·        Fundus- it is the upper part dome shaped lying above the opening of uterine part of fallopian tube.

·        Coruna- it is the part in upper corner where the oviducts enter the uterus.

·        Body- it is the main part which is narrowest inferiorly where it continues with the cervix.

·        Cervix- it is the part which joins the anterior wall of the vagina and open into it. Cavity of cervix is called cervical cavity. Cervix is communicated above with the body of the uterus by an aperture called internal-os and with the vagina by an opening the external-os

Wall of uterus is composed of three layers-

§  Perimetrium- it is the outer thin covering of peritoneum.

§  Myometrium- it is the middle thick layer of smooth muscle fiber which show strong contraction during delivery.

§  Endometrium- it is the inner glandular layer that lines the uterine cavity. The endometrium undergoes cyclic change during menstrual cycle.

4)     Vagina- (about 10cm long)

It provides a pass way for the menstrual flow, serves as the receptacle for sperm during intercourse. The opening of vagina called vaginal orifice which is partially covered by a membrane called Hyme.

External genetialia (vulva)-

1)     Mons pubis- it is the anterior most portion of the external genetial which is a cushion of fatty tissue covered by skin and pubic hair.

2)     Clitoris- Posterior to mons pubis is the clitoris which is homologous to glans penis of the male. It contains erectile tissue. Urethral orifice and vaginal orifice in the midline of the vulva.

3)     Labia majora- these are two large fleshy fold of skin which forms the boundary of vulva. They are partially covered by hair and contains large number of sebaceous (oil) gland. These are considered to be homologous to the scrotum of the male.

4)     Labia minora- these are two smaller folds of skin which lie under the labia majora. These are homologous to penile urethra of male, posterior to the labia minora are fused together to form fourchette. They also contain numerous sebaceous glands. The area between labia minor is called the vestibule. Vestibule is homologous to membranous urethra of male.

5)     Perineum- it is the area which extends from the fourchette to anus.

 

 

Gland-

1)     Vestibular gland- these are of two types

a.      The lesser vestibular gland (paraurethral gland or gland of skene) are numerous minute gland that are present on either side of the urethral orfice. These glands are homologous to the male prostrate and secret mucus.

b.      The great vestibular gland (Bartholin’s gland) are paired situated on one side of vaginal orifice.  These are homologous to bulbourethral gland of male and secrete viscid fluid that supplements lubrication during sex.

2)     Mammary gland or breast- these are modified sweat glands that tie over the pectoralis major muscles. They are also present in the male but only in a rudimentary form. At puberty they begin to develop under the influence of oestrogen and progesterone hormone. Externally each breast has a projection called nipple surrounded by a circular pigmented area of skin called areola. On the surface of areola there are numerous sebaceous glands called areolar glands. Internally the mammary gland consists of glandular tissue, the fibrous tissue and adipose tissue.