Human Female Reproductive Organs and Process of Reproduction

Female Reproductive Organs in Animated Form

All Female Reproductive Organs in a Single Page

REPRODUCTIVE SYSTEM:
The ability to reproduce is one if the properties distinguishing living from non-living matter.The mo0re primitive the animal,simpler the process of reproduction.In human being the process is one of  sexual reproduction,in which the male and female organs differ anatomically and physiologically.
  
 Both males and females produce specialised reproductive germ cell, called gametes. The male gametes are called spermatozoa and female gametes are called ova. They contain the genetic material, or genes called chromosomes,which pass inherited characteristics on to the next generation. Other body cell possess 46 chromosomes arranged in 23 pairs but the gametes contain only 23, one from each pair.Gametes are formed by meiosis . At fertilisation,the fusion of an ovum and a spermatozoon,the resulting cell is called zygote, and now possesses the full complement of 46 chromosomes.The zygote embeds itself in the wall of the uterus where it grows and develop during the 40-weeks gestation period before birth.

FEMALE REPRODUCTIVE SYSTEM

FEMALE REPRODUCTIVE SYSTEM:

UTERINE TUBES (Fallopian):
The uterine(Fallopian) tubes are about 10 cm long and extends from the sides of the uterus between the and the fundus.They lie in the upper free border of the broad ligament and their trumpet-shaped lateral ends penetrates the posterior wall, opening into the peritoneal cavity close to the overies.The end of each tube has finger like projections called fimbria,which is in close association with the ovary.

Function:
The uterine tubes move the ovum from the ovary to the uterus by peristalsis and ciliary movement.

Picture and Internal Structure of Ovary

OVARIES:
The ovaries are the female gonads(Glands producing sex hormone and ova), and they lie in a shallow fossa on the lateral walls of the pelvis.They are 2.5 to 3.5 cm long, 2 cm wide and 1 cm thick.Each is attached to the upper part of the uterus by the ovarian ligament and to the back of the broad ligament by a broad band of tissue, the mesovarium.Blood vessel and nerves pass to the ovary through the mesovarium.

Structure of the ovaries:
The ovaries have 2 layers of tissue.

Medulla:
This lies in the centre and consists of fibrous tissue, blood vessels and nerves.

Cortex:
This surrounds the medulla.It has a frame work of connective tissue or stroma, covered by germinal epithelium.It contains ovarian follicles in various stages of maturity,each of which contains an ovum.Before puberty the ovaries are inactive but the stroma already contains immature (Primordial) follicles,which the female has from birth.During the childbearing years about every 28 days, one ovarian follicle(Graafian follicle) matures,ruptures and releases its ovum into the peritoneal cavity.This is called ovulation and its occur during most menstrual cycles.

Function:
Maturation of the follicle is stimulated by follicle stimulating hormone(FSH) from the anterior pituitory; and oestrogen secreted by the follicle linning cells.Ovulation is triggered by a surge of luteinising hormone(LH) from the anterior pituitory,Which occurs a few hours before ovulation.After ovulation, the follicle linning cells develop into the corpus leutium(yellowbody),under the influence of LH from the anterior pituitory.The corpus leutium produces thye hormone progesterone and some oestrogen.

If the ovum is fertilised it embed itself in the walls of uterus where it grows and develop and produces the hormone human chorionic gonadotrophin(hCG) , which stimulate the corpus luteum to continue secreting progesterone and oestrogen for the first three month of pregnancy,after which time this function is continued by the placenta.If the ovum is not fertilised the corpus luteum an inactive mass of fibrous tissue forms, called the corpus albicans.Sometimes more than one follicle matures at a time,releasing two or more than one follicle matures  at a time,releasing 2 or more ova in the same cycle.When this happens and the ova are fertilised the result is a multiple pregnancy.

Detailed Structure and Picture of Uterus

Uterus:
The uterus is  a hollow pear shaped muscular pear-shaped organ, flattened anterio posteriorly.It lies in the pelvic cavity between the urinary bladder and the rectum.
  
In most women, it leans forward (anteversion) and is bend forward (anteflexsion) almost at right angles to the vagina, so that its anterior wall rest partly aganist the bladder below, and forming the vesicouterine pouch between the two organs.
  
When the body is upright, the uterus lies in an almost horizontal position.It is about 7.5 cm long , 5cm wide and its wall are about 2.5 cm thick.It weights from 30 to 40 grams.The parts of the uterus are the fundus, body and cervix.

Fundus:
This is the dome-shaped part of the uterus above the openings of the uterine tubes.

Body:
This is the main part. It is narrowest inferiorly at the internal os where it is continuous with the cervix.

Cervix(Neck of the uterus).
This protrudes through the anterior wall of the vagina, opening into it at the external os.

Structure:
The walls of the uterus are composed of 3 layres of tissue: Perimetrium, Myometrium, Endometrium.

Perimetrium:
This is peritoneum which is distributed diffrently on the various surfaces of the uterus.Anterior it extends over the fundus  and the body where it is folded on to the upper surface of the urinary bladder. This fold of peritoneum forms the vesticouterine pouch.Posteriorly the peritoneum extends over the fundus, of the body and the cervix, then it continues on to the rectum to form the rectouterine pouch. Laterally only the fundus is covered because the peritoneum forms the double fold with the uterine tubes in the upper free border.This double fold is the broad ligament, which at its lateral ends, attaaches the uterus to the sides of pelvis.

Myometrium:
This is the thickest layer of tissue in the uterine wall.It is a mass of smooth muscle fibres interlaced with areolar tissue,
blood vessels and nerves.

Endometrium:
This consist of columner epithelium containig a large number of mucus-secreting tubular glands.It is divided functionally
into two layers.

The functional layers: is the upper layer and its thickens and become rich in blood vessels in the first half of the menstrual cycle.

The basal layer: lies next to the myometrium, and is not lost during menstruation.It is the layer from which the fresh functional layer is regenerated during each cycle.

Functions:
After puberty, the endometrium of the uterus goes through a regular monthly cycle of changes, the menstrual cycle,under the control of hypothalamic and anterior pituitory hormones.The purpose of cycle is to prepare the uterus to receive, nourish and protect a fertilised ovum.The cycle is usually regular, lasting between 26 and 30 days.If the ovum is not fertilised anew cycle begins with a short period of bleeding (menstruation).

External Structure of Female Reproductive Organ

Clitoris:
This corresponds to the penis in the male and contains sensory nerve endings and etectile tissue, but it has no reproductive significance.

Labia majora:
These are 2 large folds froming the boundary of vulva.They are composed of skin,fibrous tissue and fat and contain large number of sebaceous glands.Anteriorly the fold join in front of the symphysis pubis, and posteriorly they merge with the skin of the perineum.At puberty, hair grows on the mons pubis and on the lateral surfaces of the labia majora.

Labia minora:
These are 2 smaller folds of skin between the labia majora,containing numerous sebaceous glands.The cleft between the labia minora is the vestibule.The vagina, urethra and ducts of the greater vestibular glands open into the vestibule.

Vagina:
The vagina is a fibromuscular tube lined with stratified squamous epithelium, connecting the external and internal organs of reproduction.It runs obliquely upwards and backwards at an angle of about 45 degree between the bladder in front and rectum and anus behind.In the adult, the anterior wall is about 7.5 cm long and the posterior wall about 9 cm long.The difference is due to the angle of insertion of the cervix through the anterior wall.

Structure:
It is 3 layered: an outer covering of areolar tissue, a middle layer of smooth muscle and an inner linning of stratified squamous epithelium that forms ridges or rugae. It has no secretory glands but the surface is kept moist by cervical secretions. Between puberty and menopause, Lactobacillus acidophilus bacteria are normally present, which secrete lactic acids, maintaining the PH between 4.9 and 3.5. The acidity inhibits the growth of most other microbes that may enter the
vagina from the perineum.

Function:
The vagina acts as receptacle for the penis during coitus, and provides an elastic passageway through which the baby passes during childbirth.

Female MENSTRUAL CYCLE

MENSTRUAL CYCLE:
This is a series of events,occuring regularly in females every 26 to 30 days throughout the childbearing period of about 36 years.The cycle consists of series of changes taking place concurrently in the ovary and uterine walls, stimulated by changes in blood concentration of hormones.Hormones secreted in a cycle are regulated by negative feedback mechanisms.  The hypothalamus secretes lutenising hormone releasing hormone (LHRH),which stimulates the anterior pituitory to secrete.

Menstrual phase:
When the ovum is not fertilised, the corpus luteum strats to degenerate.Progesterone nad oestrogen levels therefore falls, and the functional level of endometrium,which is depended on high level of these ovarian hormones, is shed in menstruation.The menstrual flow consists of the secretions from endometrial glands, endometrial cells, blood from the broken down cappilaries and the unfertilised ovum.High circulating levels of ovarian progesterone and oestrogen inhibit the anterior pituitory,blocking the release of FSH and LH, and should pregnancy occur then rising oestrogen and progesterone levels therefore prevent the maturation and release of another ovum.After degenaration of the corpus luteum,however, falling levels of oestrogen and progesterone lead to resumed anterior pituitory activity, rising FSH levels and the initiation of the next cycle.

Proliferative phase:
At this stage the ovarian follicle, stimulated by FSH, is growing towards maturity and is producing oestrogen, which stimulates proliferation of the functional layer of the endometrium in preparation for the reception of a fertilised ovum.The endometrium thickens,becoming very vascular and rich in mucus-secreting glands.This phase ends when ovulation occurs and oestrogen production by the follicle declines.

Secretory Phase:
Immediately after ovulation, the cells linning the ovarian follicle are stimulated by LH and develop into the corpus luteum,which produces progesterone and some oestrogen.Under the influence of progesterone, the endometrium becomes oedematous and the secretory galnds produce increased amounts of watery mucus.This is believed to assists the passage of the spermatozoa through the uterus to the uterine tubes where the ovum is usually fertilised.

There is a similar increase in the secretion of watery mucus by the glands of the uterine tubes and by cervical glands that lubricate the vagina. The ovum may survive in a fertilisable form for a very short time after ovulation, probably as little as 8 hours.The spermatozoa, deposited in the vagina during intercourse, may be capable of fertilising the ovum for only about 24 hours although they can survive for several days.

This means that the period of each cycle during which fertilisation can occur is relatively short.Observable changes in the women`s body occur around the time of ovulation.Cervical mucus normally thick and dry,becomes thin,elastic and watery and body temparature rises by a small but measurable amount immidiately following ovulation.Some women experience abdominal discomfort in the middle of the cycle,Thought to correspond to rupture of the follicle and release of its contents into the abdominal cavity.

If the ovum is fertilised there is no breakdown of the endometrium and no menstuation.The fertilised ovum(zygote) travels through the uterine tube to the uterus where it becomes embedded in the wall and produces Human chorionic gonadotrophin(hCG),which is similar to anterior pituitory luteinising hormone.This hormone keeps the corpus luteum intact,enabling it to continue secreting progesterone and oestrogen for the first 3 to 4 months of the pregnancy,inhibiting the maturation of further ovarian follicles.During that time the placenta develops and produces oestrogen,progesterone and gonadotrophins

The functions of female reproductive system are:
1) Formation of ova.
2) Reception of spermatozoa
3) Provision of suitable enviroments for fertilisation and fetal development.
4) Childbirth(Parturition).
5) Lactation,The production of breast milk,Which provides complete nourishment for the baby in its early life.

Different Phases of fetus within The Mother Womb

PROCESSES OF FERTILISATION:

EJACULATION:
During ejaculation which occurs at male orgasm, spermatozoa are expelled from the epididymis and pass through the deferent duct, the ejaculatory ducts and urethra.The semen is propelled by powerful rhythmical contraction of the smooth muscle in the walls of the deferent duct; the musculur contractions are sympathetically mediated.Muscle in the walls of the seminal vesicles and prostate gland also contracts adding their contents to the fluid passing through the genital ducts. The force generated by this combined processes leads to emmision of the semen through the external urethral sphincter.

Sperm comprise only 10% of the final ejaculate,the remainder being made up of seminal and prostatic fluids,which are added to the sperm during male orgasm, as well as mucus produced in the urethra.Semen is slightly alkaline, to neutralise the acidity of the vagina. Between 2 and 5 ml of semen are produced in a normal ejaculate, and contain between 40 and 100 million spermatozoa per ml.If not ejaculated, sperm gradually lose their fertility after several months and are reabsorbed by the epididymis.

Ovaries Function:

Maturation of the follicle is stimulated by follicle stimulating hormone(FSH) from the anterior pituitory; and oestrogen secreted by the follicle linning cells.Ovulation is triggered by a surge of luteinising hormone(LH) from the anterior pituitory,Which occurs a few hours before ovulation.After ovulation, the follicle linning cells develop into the corpus leutium(yellow body),under the influence of LH from the anterior pituitory.The corpus leutium produces thye hormone progesterone and some oestrogen.If the ovum is fertilised it embed itself in the walls of uterus where it grows and develop and produces the hormone human chorionic gonadotrophin(hCG) , which stimulate the corpus luteum to continue secreting progesterone and oestrogen for the first three month of pregnancy,after which time this function is continued by the placenta.If the ovum is not fertilised the corpus luteum an inactive mass of fibrous tissue forms, called the corpus albicans. Sometimes more than one follicle matures at a time,releasing two or more than one follicle matures  at a time,releasing 2 or more ova in the same cycle.When this happens and the ova are fertilised the result is a multiple pregnancy.

UTERUS AFTER FERTILISATION:
If the ovum is fertilised the zygote embeds itself in the uterine wall. The uterine muscle grows to accomodate the developing baby,which is called an embryo during its first 8 weeks, and a fetus for the remainder of pregnancy.Uterine secretion nourish the ovum before it implants in the endometrium, and after implantation the rapidly expanding ball of cells is nourished by the endometrium cells themselves. This is sufficient for only the first few weeks and the placenta is the organ that takes over thereafter.

The placenta. which is attached to the fetus by the umbilical chord, is firmly attached to the wall of the uterus, and provides the route by which the growing baby receives oxygen and nutrients, and get rids of its wastes. During pregnancy which normally lasts about 40 weeks ,the muscular wall of uterus are prevented from contracting and expelling the baby early by high levels of hormone progesterone secreted by placenta.At the end of pregnancy ( at term) the hormone oestrogen,which increases uterine contractility, becomes the predominant sex hormone in the blood. Additionally; oxytocin is released from the posterior pituitory, and also stimulates the uterine muscle.Control of oxytocin release is by positive feedback.During labour, the uterus forcefully expels the baby by means of powerful rhythmical contractions.

When Ovum is Fertilised:
If the ovum is fertilised there is no breakdown of the endometrium and no menstuation.The fertilised ovum(zygote) travels through the uterine tube to the uterus where it becomes embedded in the wall and produces Human chorionic gonadotrophin(hCG),which is similar to anterior pituitory luteinising hormone.This hormone keeps the corpus luteum intact,enabling it to continue secreting progesterone and oestrogen for the first 3 to 4 months of the pregnancy,inhibiting the maturation of further ovarian follicles.During that time the placenta develops and produces oestrogen,progesterone and gonadotrophins.

3D Animation Showing Process of Fertilization and Fetus Development in Mother`s Womb.