Reproductive system.pptx

INTRODUCTION
• The reproductive system or genital system is a
system of sex organs within an organism which work
together for the purpose of sexual reproduction.
• The ability to reproduce is one of the properties
which distinguishes living from non-living matter.
• The more primitive the animal, the simpler the
process of reproduction.
• In human beings the process is one of sexual
reproduction in which the male and female organs
differ anatomically and physiologically.

INTRODUCTION
Male & Female Reproductive Germ cells
Gametes
Male Gametes Spermatozoa
Female Gametes Ova
Chromosome Genetic Material

INTRODUCTION
• In other body cells there are 46 chromosomes
arranged in 23 pairs but in the gametes there are
only 23, one from each pair.
• When the ovum is fertilized by a spermatozoa
the resultant zygote contains 23 pairs of
chromosomes, one of each pair obtained from
the father and one from the mother.

INTRODUCTION
Functions of Female reproductive system:
• Formation of female gametes, ova
• Reception of male gametes, spermatozoa
• Provision of suitable environments for fertilization of the
ovum by spermatozoa and development of the resultant
fetus
• parturition (childbirth)
• lactation, the production of breast milk, which provides
complete nourishment for the baby in its early life.
Functions of male reproductive system:
• production of male gametes, spermatozoa
• transmission of spermatozoa to the female.

INTRODUCTION
Male Reproductive system
• Testes
• Epididymides
• Deferent ducts (Vas Deference)
• Spermatic cords
• Seminal vesicles
• Ejaculatory ducts
• Prostate gland
• Penis
Female Reproductive system
• Vagina
• Uterus
• Fallopian Tubes
• Ovaries

MALE REPRODUCTIVE SYSTEM
Testes:
• They are reproductive glands of male pigmented
in scrotum.
• 4.5 cm long, 2.5cm wide and 3cm thick
• Surrounded by 3 layers
1) Tunica vaginalis
2) Tunica albuginea
3) Tunica vasculosa

Structure of Testis:
• Each testes contains 200 to 300 lobules.
• Each lobules have 1 to 4 convoluted loops
• Loops are composed of germinal epithelial cells
Seminiferous tubules
• Between these tubules Group of interstitial cells
Testosterone

At the upper pole of testis these tubules combined
Single tubule
(6 meter in length, folded and tightly packed)
This mass is called as Epididymis
Leaves the scrotum as deferent duct (vas deference)

Function of testes:
• To produce spermatozoa
• To secret hormone called as testosterone
Spermatozoa:
Produce in seminiferous tubules
(Production of sperm controlled by FSH)
Mature and store in to epididymis

Head:
• Completely filled by nucleus containing DNA and enzymes required to
penetrate the outer layer of the ovum to reach and fuse with its nucleus.
Body:
• Packed with mitochondria, which fuel the propelling action of the tail that
powers the sperm on its journey into the female reproductive tract.
Tail:
• Only fibril and like flagella and has ciliary characteristics

• Successful spermatogenesis takes place at a
temperature about 3°C below normal body
temperature.
• The testes are cooled by their position outside
the abdominal cavity, and the thin outer
covering of the scrotum has very little insulating
fat.

• There are about 1 lac spermatozoa per cmm of
semen.
• Each ejaculation contains a few cc of semen. Hence
there are trillions of spermatozoa for every
discharge.
• If there are less than 20 millions of spermatozoa per
cc in the semen, then fertilization generally does
not occur.
• They are very minute and sensitive and can be alive
for 1 to 2 months.
• In the female genital tract they hardly live for 2 to 3
days.

Testosterone:
• Derived from two sources
1) Testes
2) Adrenal cortex (In Minute quantity)
Functions:
• Growth of sex organs like testes, and development of
prostate, seminal vesicles and ejaculatory duct.
• To maintain life and fertility of spermatozoa.
• Development of secondary sex characteristics like
appearance of mustache, beard and hair in axillary, pubic
and chest regions and hoarseness of voice.
• Manly spirit also develops in male.

• Bony and muscular structure become more heavy
and stronger because of stimulation of anabolic
function of testosterone.
• Metabolism is also stimulated.
• Blood volume and RBCs are more in male than
female because of anabolic function of
testosterone.
• Libido is inspired because of testosterone.

Spermatic cord:
• The spermatic cords suspend the testes in the scrotum.
• The cord is covered in a sheath of smooth muscle and
connective and fibrous tissues and is attached to the testis
on the posterior wall.
• Each cord contains
1) Testicular artery : Branches from the abdominal aorta
2) Testicular veins: Passes in to abdominal cavity and join
with inferior venacava
3) Lymph drainage: Through lymph node around the aorta
4) Nerve supply: By branches of thoracic nerves

Vas deference:
• 45 cm long
• Passes upwards from
the testes towards
posterior wall of
bladder
• Join with duct from
seminal vesicles and
form ejaculatory duct

Seminal vesicles:
• Two small fibromuscular pouches lined with columnar
epithelium, lying on the posterior side of bladder.
• Its lower end opens with small duct which join with
deferent duct and form a ejaculatory duct.
Function:
• It stored fluid content called as seminal fluid.
• It contract and expel this seminal fluid during ejaculation.
• Seminal fluid forms 60% bulk of semen (fluid ejaculated by
male sex organs)
• Seminal fluid contains nutrients to support the sperm
during their journey through the female reproductive tract.

Ejaculatory ducts:
• The ejaculatory ducts are two tubes about 2 cm
long, each formed by the union of the duct from a
seminal vesicle and a deferent duct.
• They pass through the prostate gland and join the
prostatic urethra, carrying seminal fluid and
spermatozoa to the urethra.
• The ejaculatory ducts are composed of the same
layers of tissue as the seminal vesicles.

Prostate gland:
• The prostate gland lies in the pelvic cavity in front of the
rectum.
• It consists of an outer fibrous covering, a layer of smooth
muscle and glandular substance composed of columnar
epithelial cells.
• The prostate gland secretes a thin, milky fluid that makes
up about 30% of semen, and gives it its milky appearance.
• It is slightly alkaline, which provides a protective local
environment for sperm arriving in the acidic vagina.
• It also contains a clotting enzyme, which thickens the
semen in the vagina, increasing the likelihood of semen
being retained in the vicinity of the cervix.

Urethra:
• The male urethra provides a common pathway for
the flow of urine and semen.
• 19 to 20 cm long and consist 3 parts
1) Prostatic urethra : Originates from bladder and
passes through prostate gland
2) Membranous urethra: shortest and narrowest part
and extends from the prostate gland to the bulb of
the penis.
3) Penile Urethra (Spongiose): Lies within the corpus
spongiosum of the penis and terminates at the
external urethral orifice in the glans penis.

• There are two urethral sphincter
1) Internal sphincter: consists of smooth muscle
fibres at the neck of the bladder above the
prostate gland.
2) External sphincter: consists of skeletal muscle
fibres surrounding the membranous part.

Penis:
• The penis has root and body.
• The root lies in the perineum and the body surrounds the urethra
• It is formed by three cylindrical masses of erectile tissue and
involuntary muscle. The erectile tissue is supported by fibrous
tissue and covered with skin and has a rich blood supply.
• The two lateral columns are called the corpora cavernosa and the
column between them, containing the urethra, is the corpus
spongiosum.
• At its tip it is expanded into a triangular structure known as the
glans penis.
• Just above the glans the skin is folded upon itself and forms a
movable double layer, the foreskin.

• Arterial blood is supplied by deep, dorsal and bulbar
arteries of the penis which are branches from the internal
pudendal arteries.
• A series of veins drain blood to the internal pudendal and
internal iliac veins.
• The penis is supplied by autonomic and somatic nerves.
• Parasympathetic stimulation leads to filling of the spongy
erectile tissue with blood, caused by arteriolar dilatation
and venoconstriction, which increases blood flow into the
penis and obstructs outflow.
• The penis therefore becomes engorged and erect, an
essential prerequisite for coitus to occur.

Ejaculation:
• Ejaculation is process which occurs at the point of male
orgasm where spermatozoa are expelled from the
epididymis and pass through the deferent duct, the
ejaculatory duct and the urethra.
• The semen is propelled by powerful rhythmical contraction
of the smooth muscle in the walls of the deferent duct and
the muscular 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 these combined processes leads to
emission 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.
• 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.

Puberty in Male:
• This occurs between the ages of 10 and 14.
• Luteinizing hormone from the anterior lobe of the
pituitary gland stimulates the interstitial cells of the
testes to increase the production of testosterone.
• This hormone influences the development of the
body to sexual maturity.
• In the male, fertility and sexual ability tend to decline
gradually with ageing.
• The secretion of testosterone gradually declines,
usually beginning at about 50 years of age.

• The changes which occur at puberty are:
 Growth of muscle and bone and a marked increase
in height and weight.
 Enlargement of the larynx and deepening of the
voice.
 Growth of hair on the face, axillae, chest, abdomen
and pubis.
 Enlargement of the penis, scrotum and prostate
gland.
 Maturation of the somniferous tubules and
production of spermatozoa.
 The skin thickens and becomes more oily.

FEMALE REPRODUCTIVE SYSTEM
• Female reproductive system is divided into
1) External organs (External genitalia)
 Labia Majora
 Labia Minora
 Clitoris
 Hymen
 Vestibular glands
2) Internal organs (Internal genitalia)
 Vagina
 Uterus
 Fallopian Tubes
 Ovaries
3) Accessory organ
 Mammary gland or Breast

Labia Majora:
• These are the two large folds which form the
boundary of the vulva.
• They are composed of skin, fibrous tissue and fat
and contain large numbers of sebaceous glands.
• Anteriorly the folds 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 two 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.

Clitoris:
• The clitoris corresponds to the penis in the male
and contains sensory nerve endings and erectile
tissue but it has no reproductive significance.
Hymen:
• The hymen is a thin layer of mucous membrane
which partially occludes the opening of the
vagina.
• It is normally incomplete to allow for passage of
menstrual flow.

Vestibular glands:
• The vestibular glands (Bartholin's glands) are situated
one on each side near the vaginal opening.
• They are about the size of a small pea and have
ducts, opening into the vestibule immediately lateral
to the attachment of the hymen.
• They secrete mucus that keeps the vulva moist.
Perineum:
• The perineum is the area extending from the base of
the labia minora to the anal canal.
• It is roughly triangular and consists of connective
tissue, muscle and fat.

Internal Genitalia

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° 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 of vagina:
1) Outer covering: Areolar tissue
2) Middle layer: Smooth muscles
3) Inner lining: Stratified squamous epithelium
Ridges or rugae
• It has no secretory glands but the surface is kept
moist by cervical secretions.

• Between puberty and the menopause,
Lactobacillus acidophilus bacteria are normally
present, which secrete lactic acid, 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.

Blood supply:
• Arterial supply Arterial plexus
Uterine and vaginal artery
Branches of Internal ileac arteries Abdominal Aorta
Nerve supply:
• Parasympathetic fibres from sacral outflow
• Sympathetic fibres from lumbar outflow

Functions of Vagina:
• Acts as the receptacle for the penis during coitus.
• Provides an elastic passageway through which
the baby passes during childbirth.
• Inhibit the growth of micro-organism from
perineum by acidic pH.

Uterus:
• The uterus is a hollow muscular pear-shaped organ,
flattened anteroposteriorly.
• Lies in the pelvic cavity between the urinary bladder
and the rectum.
• In most women, it bent forward almost at right
angles to the vagina.
• When the body is in the upright position the uterus
lies in an almost horizontal position. It is about 7.5
cm long, 5 cm wide and its walls are about 2.5 cm
thick.
• It weighs from 30 to 40 grams.

Three Parts of uterus
• 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 orifice where it is
continuous with the cervix.
• Cervix ( Neck of Uterus): This protrudes through
the anterior wall of the vagina, opening into it at
the external orifice.

Structure:
• Wall of uterus
composed of 3 layers
of tissue.
1) Perimetrium
2) Myometrium
3) Endometrium

Perimetrium:
• Outer layer is peritoneum, which is distributed differently
on the various surfaces of the uterus.
• Anteriorly 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 vesicouterine pouch.
• Posteriorly the peritoneum extends over the fundus, the
body and the cervix, then it continues on to the rectum to
form the rectouterine pouch.
• Peritoneum forms a double fold with the uterine tubes in
the upper free border. This double fold is the broad
ligament which, at its lateral ends, attaches the uterus to
the sides of the 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 consists of columnar epithelium containing a
large number of mucus-secreting tubular glands.
• It is divided functionally into two layers.

• The functional layer is the upper layer and it thickens and
becomes rich in blood vessels in the first half of the
menstrual cycle. If the ovum is not fertilized and does not
implant, this layer is shed during menstruation.
• 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.
• The upper two-thirds of the cervical canal is lined with this
mucous membrane.
• Further towards the vagina, however, the mucosa changes,
becoming stratified squamous epithelium, which is
continuous with the lining of the vagina itself.

Blood supply:
• Arterial supply Uterine arteries Internal ileac arteries
Abdominal aorta
• Venous Drainage Uterine veins Internal ileac veins
Inferior venacava
Nerve Supply:

Functions of Uterus:
• After puberty, the endometrium of the uterus goes
through a regular monthly cycle of changes, the
menstrual cycle, which is under the control of
hypothalamic and anterior pituitary hormones.
• The purpose of the 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 a new cycle begins with a
short period of bleeding(menstruation).

• If the ovum is fertilised the zygote embeds itself in the uterine wall.
• The uterine muscle grows to accommodate the developing baby,
which is called an embryo during its first 8 weeks, and a fetus for the
remainder of the pregnancy.
• Uterine secretions nourish the ovum before it implants in the
endometrium, and after implantation the rapidly expanding ball of
cells is nourished by the endometrial 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 cord, is
firmly attached to the wall of the uterus, and provides the means by
which the growing baby receives oxygen and nutrients, and gets rid
of its wastes.

• During pregnancy, which normally lasts about 40
weeks, the muscular walls of the uterus are
prevented from contracting and expelling the baby
early by high levels of the hormone progesterone
secreted by the placenta.
• At the end of pregnancy (at term) the hormone
estrogen, which increases uterine contractility,
becomes the predominant sex hormone in the blood.
• Additionally, oxytocin is released from the posterior
pituitary, 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.

Fallopian tubes:
• The uterine tubes are about 10 cm long and extend
from the sides of the uterus between the body and
the fundus.
• They lie in the upper free border of the broad
ligament and their trumpet-shaped lateral ends
penetrate the posterior wall, opening into the
peritoneal cavity close to the ovaries.
• The end of each tube has fingerlike projections called
fimbriae. The longest of these is the ovarian fimbriae
which is in close association with the ovary.

Structure:
Outer covering: Peritoneum (Broad ligaments)
Middle Layer: Smooth Muscles
Inner layer: lined with ciliated epithelium
Function:
• The uterine tubes convey the ovum from the ovary to the
uterus by peristalsis and ciliary movement.
• The mucus secreted by the lining membrane provides
ideal conditions for movement of ova and spermatozoa.
• Fertilisation of the ovum usually takes place in the uterine
tube, and the zygote is propelled into the uterus for
implantation.

Ovaries:
• The ovaries are the female gonads, or glands, and
they lie 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 vessels and nerves pass to the ovary through
the mesovarium.

Histology: 2 layers
Medulla:
• This lies in the centre and consists of fibrous tissue, blood vessels and nerves.
Cortex:
• This surrounds the medulla.
• It has a framework 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
(Grafian follicle) matures, ruptures and releases its ovum into the peritoneal
cavity.
• This is called ovulation and it occurs during each menstrual cycles.

Blood supply:
Arterial supply Ovarian arteries Abdominal aorta
Venous Drainage Ovarian veins Inferior venacava
Nerve supply:

Puberty in female:
• Puberty is the age at which the internal reproductive
organs reach maturity and marks the beginning of
the childbearing period.
• The ovaries are stimulated by the gonadotrophins
from the anterior pituitary, follicle stimulating
hormone and luteinizing hormone.
• The age of puberty varies between 10 and 14 years
and a number of physical and physiological changes
take place at this time.

• The uterus, the uterine tubes and the ovaries reach
maturity.
• The menstrual cycle and ovulation begin.
• The breasts develop and enlarge.
• Pubic and axillary hair begins to grow.
• There is an increase in the rate of growth in height
and widening of the pelvis
• There is an increase in the amount of fat deposited in
the subcutaneous tissue, especially at the hips and
breasts.

MENSTRUAL CYCLE
• This is a series of events, occurring regularly in
females every 26 to 30 days throughout the
childbearing period of about 36 years.
• The cycle consists of a series of changes that take
place concurrently in the ovaries and uterine
walls, stimulated by changes in the blood
concentrations of hormones.
• Hormones secreted in the cycle are regulated by
feedback mechanisms.

MENSTRUAL CYCLE
• The hypothalamus secretes luteinizing
hormone releasing factor (LHRF) which
stimulates the anterior pituitary to
secrete
1) Follicle stimulating hormone (FSH),
which promotes the maturation of
ovarian follicles and the secretion of
estrogen, leading to ovulation.
2) Luteinizing hormone (LH), which
triggers ovulation, stimulates the
development of the corpus luteum
and the secretion of progesterone.
• The hypothalamus responds to changes
in the blood levels of estrogen and
progesterone. It is switched off by high
levels and stimulated when they are
low.

MENSTRUAL CYCLE
• The average length of the menstrual cycle is about
28 days.
• The cyclic changes during menstrual cycle can be
divided into four phases:
1) Menstrual phase
2) Proliferative phase
3) Ovulation
4) Secretive phase

MENSTRUAL CYCLE
1) Menstrual phase:
• When the ovum is not fertilised, the corpus luteum starts
to degenerate. (In the event of pregnancy, the corpus
luteum is supported by human chorionic gonadotrophin
(hCG) secreted by the developing embryo.)
• Progesterone and estrogen levels therefore fall, and the
functional layer of the endometrium, which is dependent
on high levels 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 capillaries and the unfertilized ovum.
• This phase lasts for 4 to 5 days.

MENSTRUAL CYCLE
• If fertilisation occur human chorionic gonadotrophin (HCG)
will be secreted from zygote and this hcg prevents the
degeneration of corpus luteum.
• Corpus luteum will continue to secrete progesterone and
estrogen. High level of these hormones in blood will inhibit
the anterior pituitary gland to secret FSH and LH.
• If FSH and LH will not secreted, the maturation of new
ovum will not occur.
• But if fertilization does not occur, there is degeneration of
corpus luteum and the level of progesterone and estrogen
declined which stimulate anterior pituitary gland by
hypothalamus and secret FSH and LH for the maturation of
new ovum for next cycle.

MENSTRUAL CYCLE
2) Proliferative phase:
• At this stage an ovarian follicle, stimulated by FSH, is
growing towards maturity and is producing estrogen.
• Estrogen stimulates the proliferation of the functional layer
of the endometrium in preparation for the reception of a
fertilised ovum.
• The endometrium becomes thicker by rapid cell
multiplication accompanied by an increase in the numbers
of mucus-secreting glands and blood capillaries.
• This phase ends when ovulation occurs and estrogen
production declines.
• This phase lasts for 10 days i.e form 5th to 14th day.

MENSTRUAL CYCLE
3) Ovulation
• After the maturation of graffian follicle in
proliferative phase by FSH, the high level of LH
causes rupture of graffian follicle of one ovary to
liberate ovum. This is called as Ovulation.
• Ovulation occur on the 14th day of menstrual
cycle.

MENSTRUAL CYCLE
4) Secretary phase:
• Immediately after ovulation, the lining cells of the ovarian
follicle are stimulated by LH to develop the corpus luteum,
which produces progesterone and some estrogen.
• Under the influence of progesterone the endometrium
becomes edematous and the secretary glands produce
increased amounts of watery mucus.
• This is believed to assist 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
which lubricate the vagina.

SPERMATOGENESIS
• Spermatogenesis occurs in the seminiferous tubules during
active sexual life as the result of stimulation by anterior
pituitary gonadotropic hormones, beginning at an average
age of 13 years and continuing throughout most of the
remainder of life but decreasing markedly in old age.
• The spermatozoa are generated from spermatogonia.
• Spermatogonia is the male germ cell which contains both
23 paternal as well as maternal 23 chromosomes which are
single stranded. So they contains 2n chomosomes.
Therefore they are called as dipoloids.
• Now DNA replication occurs and the single stranded
spermatogonia is converted in to double stranded cell. This
type of cell are called as primary gamets or primary
spermatocyte. This primary spermatocytes also contains 23
pair of chromosomes. So they are also called as diploids.

SPERMATOGENESIS
• In next step the primary spermatocyte undergoes
meiosis-I process in which the diploid spermatocytes
are converted into two haploids which are called as
secondary spermatocytes. Each secondary
spermatocytes are double stranded and contain 23
chromosomes.
• In final stage there is breakdown of each
chromosomes from centromere from both secondary
spermatocytes and converted into four spermatids.
This is called as meiosis-II.
• These spermatids become mature and converted into
final mature spermatozoa. They are haploids and
each contains 23 chromosomes.

OOGENESIS
• Oogenesis is the process of production and
development of an ovum from oogonia.
• Oogonia is the female germ cell which contains both
23 paternal as well as maternal 23 chromosomes
which are single stranded. So they contains 2n
chromosomes. Therefore they are called as dipoloids.
• Now DNA replication occurs and the single stranded
oogonia is converted in to double stranded cell. This
type of cell are called as primary gamets or primary
oocyte. This primary oocytes also contains 23 pair of
chromosomes. So they are also called as diploids.

OOGENESIS
• In next step the primary oocyte undergoes meiosis-I
process in which the primary oocytes is converted into
two haploids in which one cell acquired most of the
cytoplasm from the primary oocyte which is called as
secondary oocyte and other is called as polar body.
Secondary oocyte and polar body contain 23
chromosomes.
• In final stage there is breakdown of each chromosomes
from centromere from secondary oocytes and converted
into one ootids and one polar bodies. Ootide acquired
most of the cytoplasm. One polar body converted into two
more polar bodies. This is called as meiosis-II.
• The ootid become mature and converted into final mature
ovum. It is haploid and contains 23 chromosomes.

FERTILIZATION
• It is a process of fusion of male and female gamets.
• Fertilization is co-ordinated sequence of molecular
and cellular process which begins with the contact
of oocyte and sperm and ends with intermingling of
maternal and paternal chromosomes at metaphase
of first mitotic division of zygote.
• Fertilization occurs at the ampulla of fallopian tube.
• So before to start the process the ovum and sperm
need to travel and reach to the ampulla of fallopian
tube.

FERTILIZATION
Transport of Ovum:
• Sperm is motile cell but ovum is non motile. So ovum is travelled with the
help of other organs.
• When the graffian follicle ruptured during ovulation the ovum is
surrounded by number of follicular cell and they are called as corona
radiata.
• At the time of ovulation the fimbriae of infundibulum become very active
and start sweeping on the ovary.
• The mucosal cell in the fimbriae are ciliated so the sweeping action of
fimbriae and ciliated mucosa pick up the ovum from ovary to fallopian
tube.
• This time the ovum is secondary oocyte it is not a definite ovum.
• Normal life of this secondary oocyte is 1 to 2 days and after that it died.
• The peristaltic movement of fallopian tube moves ovum through fallopian
tube.

FERTILIZATION
Transport of Sperm:
• Approximately 200-500 million sperm deposited in one
ejaculation in the vagina.
• The semen contains clotting enzyme from prostatic fluid
which thickens the semen to remain sperm at the cervix.
• Tail of the sperm helps sperm to travel through vagina to
ampulla of fallopian tube through uterus.
• Even contraction of uterus and fallopian tube and cilia
inside fallopian tube help sperm to travel through female
reproductive organs.
• The energy required for the movement of tail provided by
fructose from seminal fluid.
• It will take 5 min to reach fist sperm to the ovum at the
ampulla.

FERTILIZATION
• Now sperm and ovum has to pass different reaction.
1) Capacitation reaction:
• The head of sperm has double layer of cellular membrane
and on this double membrane have number of
glycoproteins.
• With these glycoproteins sperm can not reach zona
pellucida layer of ovum.
• These glycoproteins are washed away and removed by
ciliary movement of cilia in mucosa of fallopian tube
which take about 7 hours.
• Simultaneusly the cilia also wash the corona radiata
surround the ovum.
• Now the sperm can easily reach to zona pellucida of
ovum.

FERTILIZATION
2) Acrosome reaction:
• When sperm cross the corona radiata and touches to
the zona pellucida, first layer of ovum, the ovum
produce acrosome reaction to the sperm.
• In this reaction the double layer of sperm membrane
fuse with each other at different site.
• After the fusion the layer melt away from non- fusion
portion part and release enzymes i.e acrosin, trypsin
like substance and halloronidase.
• These enzymes causes digestion of zona pellucida
and sperm directly attach with ovum.

FERTILIZATION
3) Cortical reaction:
• Number of sperm try to pass through capacitation
and acrosome reaction but when first sperm pass
both reaction and attached to membrane of
ovum, ovum release lysozomal enzymes.
• These lysozomal enzymes causes structural and
functional changes in zona pellucida and it
become impermeable to other sperm.
• This is called as cortical reaction.

FERTILIZATION
4) Completion of second mitotic division:
• Now, the sperm leave the cell membrane and enters in to
ovum and it contains 23 chromosomes.
• Simultaneously the ovum which is secondary oocyte
undergoes secondary mitotic division and form a one
definite ovum and polar bodies.
• This definite ovum also contains 23 chromosomes.
• The genetic material of ovum is called as female pronucleus
and genetic material of sperm is called as male pronucleus.
• Now both pronucleus moves towards each other and by
intermingling of maternal and paternal chromosome occurs
and form a single cell with 46 chromosome.

FERTILIZATION
5) Metabolic Activation:
• This single cell with 46 chromosomes is called as embryo.
• Because of metabolic activation there is cleavage of
embryo and the embryo will be converted into two cell.
• The subsequent cleavage will be continued and two cell
form 4 cell then 8 cell, 16 cell and 32 cell.
• This process occurs in fallopion tube with moving condition.
• After that this fertilized ovum reach to uterus. Here the
inner cell comes together and the extra space filled with
uterine fluid. And it is called as blastocyst.
• Now this blastocyst removes its membrane and then
implant into endometrium and form placenta, umbilical
cord and start to grow a baby.

PREGNANCY
• When ovum is fertilized, pregnancy ensues and proceed for
40 weeks and then terminate into parturition resulting in
the birth of a baby.
Physiological Changes:
• During the pregnancy, a series of progressive changes take
place.
1. Uterus, its placenta, ovaries and breasts enlarge. Vagina
widens and pelvic ligaments relax.
2. Blood volume increases and accordingly plasma iron
decreases.
3. Cardiac output is increased and blood pressure is
decreased.
4. Morning sickness i.e nausea – vomiting occurs and
constipation develops

PREGNANCY
5) Respiration and vital capacity increased.
6) Endocrine glands are stimulated. Thyroid,
parathyroid and adrenal cortex are enlarged.
7) Carbohydrate, Protein and fat metabolism are
stimulated and result in glycosuria, lipidemia and
water retention.
8) Sometimes sugar appears in urine. Estrogens,
progesterone and gonadotropic hormones of
placenta also excreted in urine.

PREGNANCY
Examination of fetus:
• Examination of fetus can be done by two methods i.e
Amniocentesis and Ultarsonography.
• In amniocentesis method after the twelth week of
pregnancy a sterile needle is inserted through mother’s
abdomen that holds the fluid surrounding the fetus. Then
this fluid is examined by genesist. By examination of the
chromosomal structure and enzyme components of cells in
the fluid, one can identify various types of inherited
defects. It is also use for the determination of the sex of the
child based of its chromosomal set up.
• Other method is ultrasonography which employs sound
waves to produce a two dimensional image of fetus.

PREGNANCY
Placenta:
• It is a round plate like structure which develops
within the endometrial with a maternal and fetal
surface which serves as channel for nutritive,
respiratory and excretory functions to fetus.
• The maternal and fetal plates of placenta are fully
zigzag thin semi permeable membranes.
• Respiratory gases, nutrition, excretion etc pass out
through these channels.
• The fetus is bound to mother’s uterus through a
umbilical cord.

PREGNANCY
Functions:
• The placenta so to say represents fetus’ lung, liver,
kidney, and thus serves important respiratory,
digestive, excretory and other important functions.
• The functions of placenta are nutritive, respiratory,
storage, hormonal, and excretory.
• The hormones are not just stored but secreted by
placenta. These hormones are human chorionic
gonadotrophins, estrogens, progesterone, prolactin
or placental growth hormone and relaxin.

PARTURITION
• The parturition occurred by the uterine contraction and this
uterine contraction is generated by two hormones i.e estrogen
and oxytocin.
• With each uterine contraction, the mother experiences
considerable pain. The cramping pain in early labor is probably
caused mainly by hypoxia of the uterine muscle and stretching
of cervix.
• The uterine contractions during labor begin mainly at the top
of the uterine fundus and spread downward over the body of
the uterus.
• Also, the intensity of contraction is great in the top and body of
the uterus but weak in the lower segment of the uterus
adjacent to the cervix.
• Therefore, each uterine contraction tends to force the baby
downward toward the cervix.

PARTURITION
• In the early part of labor, the contractions might occur only once every
30 minutes.
• As labor progresses, the contractions finally appear as often as once
every 1 to 3 minutes, and the intensity of contraction increases greatly,
with only a short period of relaxation between contractions.
• The combined contractions of the uterine and abdominal musculature
during delivery of the baby cause a downward force on the fetus of
about 25 pounds during each strong contraction.
• It is fortunate that the contractions of labor occur intermittently,
because strong contractions impede or sometimes even stop blood
flow through the placenta and would cause death of the fetus if the
contractions were continuous.
• Indeed, overuse of various uterine stimulants, such as oxytocin, can
cause uterine spasm rather than rhythmical contractions and can lead
to death of the fetus.

PARTURITION
• In about 95 per cent of births, the head is the first part of the baby
to be expelled, and in most of the remaining instances, the
buttocks are presented first.
• The head acts as a wedge to open the structures of the birth canal
as the fetus is forced downward.
• The first major obstruction to expulsion of the fetus is the uterine
cervix.
• Toward the end of pregnancy, the cervix becomes soft, which
allows it to stretch when labor contractions begin in the uterus.
• The so-called first stage of labor is a period of progressive cervical
dilation, lasting until the cervical opening is as large as the head of
the fetus.
• This stage usually lasts for 8 to 24 hours in the first pregnancy but
often only a few minutes after many pregnancies.

PARTURITION
• Once the cervix has dilated fully, the fetal
membranes usually rupture and the amniotic
fluid is lost suddenly through the vagina.
• Then the fetus’s head moves rapidly into the birth
canal, and with additional force from above, it
continues to wedge its way through the canal
until delivery is effected.
• This is called the second stage of labor, and it may
last from as little as 1 minute after many
pregnancies to 30 minutes or more in the first
pregnancy.

PARTURITION
• For 10 to 45 minutes after birth of the baby, the uterus continues to contract to a
smaller and smaller size, which causes a shearing effect between the walls of the uterus
and the placenta, thus separating the placenta from its implantation site.
• Separation of the placenta opens the placental sinuses and causes bleeding.
• The amount of bleeding is limited to an average of 350 milliliters by the following
mechanism:
• The smooth muscle fibers of the uterine musculature are arranged in figures of eight
around the blood vessels as the vessels pass through the uterine wall.
• Therefore, contraction of the uterus after delivery of the baby constricts the vessels
that had previously supplied blood to the placenta.
• In addition, it is believed that vasoconstrictor prostaglandins formed at the placental
separation site cause additional blood vessel spasm.

Reproductive system.pptx

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