Welcome to an in-depth presentation on the Human Reproductive System. This comprehensive guide is designed to equip you with detailed knowledge, making it an invaluable resource for extensive study and preparation for a range of competitive exams, including NEET, CUET, and board exams. Whether you're delving into the subject for the first time or looking for a comprehensive revision tool, this presentation offers a deep dive into the intricacies of the human reproductive system. Explore essential concepts, structures, and functions, all presented in a clear and accessible format. Elevate your understanding and enhance your exam readiness with this indispensable resource. Start your journey towards mastering the Human Reproductive System today!

1. HUMAN
REPRODUCTION
Class- XII

2. OVERVIEW
 Humans are unisexual organisms and undergo sexual
reproduction.
 Reproductive units are specialized cells called gametes:
sperm and egg or ova.
 Sperms are produced in the testes, and ova are produced
in the ovaries.
 Testes and ovaries are the primary sex organs or gonads in
humans.
 Besides producing gametes, gonads also secrete sex
hormones.
 Sexual dimorphism: Males and females have different
secondary sexual features.

4. MALE REPRODUCTIVE SYSTEM -
OVERVIEW
 Located in the pelvic
region and consists
of various structures.
 Primary structures:
Scrotal sac, Testes,
Tunicae,
Seminiferous
tubules, and Leydig
cells.

6. SCROTAL SAC (SCROTUM)
 Testes are situated outside the
abdominal or pelvic cavity in the
scrotal sac.
 Acts as a thermoregulator to
maintain testicular temperature
lower than the body
temperature.
 Optimum temperature for sperm
production (spermatogenesis).
 Biologically homologous to the
labia majora in females.

7. TESTES
 Primary male gonads.
 Oval-shaped organs,
located in the scrotum.
 Develop in the
abdominal cavity
during early fetal life
and descend into the
scrotum later.
 Tunicae of testis:
Tunica vaginalis,
Tunica albuginea,
Tunica vasculosa.

8. SEMINIFEROUS TUBULES
 Coiled tubules inside the
testes where sperms are
produced
(spermatogenesis).
 Sertoli cells (Supporting
cells), Spermatogenic cells,
Leydig cells (Interstitial
cells).

9. VASA EFFERENTIA AND EPIDIDYMIS
 Vasa Efferentia:
Collect sperm from
inside the testis and
transfer them to the
epididymis.
 Epididymis: Coiled
tube that stores and
matures sperm
temporarily.

10. VAS DEFERENS (SPERM DUCT)
 Straight tube that carries
sperm from the
epididymis to the urethra.
 Most of the sperm is
stored in the vas
deferens.

11. SEMINAL VESICLES:
 Paired tubular glands located
below the urinary bladder.
 Secrete alkaline nutritive
seminal fluid, a significant
component of ejaculate.
 Components of seminal fluid:
Fructose, citrate, inositol,
prostaglandins, and several
proteins.
 Presence of fructose confirms
sexual intercourse.

12. PROSTATE GLAND:
 Single, large, and spongy gland
surrounding the first part of the
urethra.
 Consists of 30-40 tubuloalveolar
glands.
 Secretes a slightly acidic (pH-6.5)
milky fluid with various components
like calcium, citrate ion, phosphate
ion, and enzymes.
 Prostate gland secretion nourishes
and activates spermatozoa for
motility.

13. IMPORTANCE OF PROSTATE GLAND:
 Essential for sperm motility
and fertility.
 Removal of the prostate
gland causes sterility in
males.
 The gland's position around
the urethra facilitates the
release of its secretion
during ejaculation.

14. COWPER'S GLANDS:
 Also known as bulbourethral glands.
 Situated beneath the bladder and behind
the urethra.
 Secrete a slightly alkaline, viscous mucus
during sexual stimulation for lubrication of
the penis.
 Neutralizes any residual acidic urine in the
urethra.
 The secretion of Cowper's glands carries
some spermatozoa released before
ejaculation.
 The presence of sperm in pre-ejaculatory
fluid is a factor contributing to the
withdrawal method's higher failure rate as a
birth control method.

15. URETHRA AND PENIS
 Urethra: Carries both
urine from the
bladder and sperm
from the vas
deferens.
 Penis: Male external
genitalia, spongy and
erectile tissue.
 Erects during sexual
arousal for
copulation and
sperm transmission.

16. SEMEN
 Ejaculated during the male sexual
act.
 Composed of sperm and fluids from
the vas deferens, seminal vesicles,
prostate gland, and Cowper's
glands.
 Average pH: 7.5, Lifespan of sperm:
24-48 hrs.
 Sperm can be preserved for many
years at temperature below -100°C
(cryopreservation).

19. FEMALE REPRODUCTIVE SYSTEM -
OVERVIEW
The female
reproductive system
consists of ovaries,
fallopian tubes, uterus,
vagina, and external
genitalia.
Its components are
found in both paired
and unpaired

20. OVARIES - PRIMARY SEX ORGANS
 Ovaries are the primary
sex organs of a woman,
located near the kidneys.
 Germinal epithelium
covers the free surface of
ovaries, continuous with
the peritoneum.
 Ovarian stroma is divided
into outer cortex and
inner medulla, covered
by tunica albuginea.

21. FALLOPIAN TUBES
 Also known as oviducts or
Mullerian ducts, two small
tubes located near the
uterus.
 The lumen of oviduct is
lined by ciliated epithelium,
facilitating the movement of
ovum.
 Infundibulum with fimbriae,
ampulla (site for
fertilization), and isthmus
leading to uterus.
Infundibulum is the funnel-shaped part, which
lies near to oviduct. Its edges possess finger-like
projections called fimbriae, which helps in the
collection of ovum after ovulation.
The infundibulum leads to a wider part of oviduct
called ampulla. It is the site for fertilization.
Isthmus is the last part having a narrow, thick -
walled lumen and leads to uterus.

22. UTERUS - WALL LAYERS
 Uterus has three
layers: perimetrium
(thin outer covering),
myometrium (thick
muscular layer), and
endometrium (inner
mucosal lining).
 Endometrium
undergoes cyclical
changes during
menstruation.

23. VAGINA
 Muscular tube extending
from cervix to vestibule,
acting as a copulation and
birth canal.
 Vagina's acidic pH (about
4.0) prevents the growth of
harmful microorganisms.
 Vaginal orifice partially
covered by the hymen, which
may rupture during the first
coitus or through physical
activity.

24. EXTERNAL GENITALIA - VULVA
 The external genital
structure of the female
reproductive system.
 Comprises the mons
pubis, labia majora,
labia minora, clitoris,
fourchette, and
perineum.
 Clitoris is homologous
to the male's penis.

25. FEMALE ACCESSORY GLANDS - VESTIBULAR
GLANDS
 Lesser vestibular glands
(paraurethral or Skene's
glands) and greater
vestibular glands
(Bartholin's glands).
 Lesser vestibular glands
secrete mucus, and
greater vestibular glands
secrete alkaline secretion
for lubrication.

26. MAMMARY GLANDS
 Mammary or milk-
producing glands found in
each breast.
 Develop under the
influence of estrogen and
progesterone during
puberty.
 Prolactin stimulates milk
production, and oxytocin
stimulates milk ejection
into ducts.

27. COMPOSITION OF MILK
Milk secreted by
mammary glands
contains casein,
lactose, fat droplets,
water, mineral salts,
and vitamins.
Milk is poor in iron
content and vitamin C.

31. CONCLUSION
The female
reproductive system is
complex and essential
for reproduction.
Understanding its
components and
functions is crucial for
reproductive health and
development.

32. GAMETOGENESIS
 Definition: The process of
forming haploid gametes
from undifferentiated,
diploid germ cells in the
gonads of both males and
females.
 Two Types:
Spermatogenesis (in males)
and Oogenesis (in females).
 Importance: Essential for
sexual reproduction and
passing on genetic material
to offspring.

33. SPERMATOGENESIS
Definition: The
process of sperm
formation from
Primordial Germ Cells
(PGC) in the testes.
Occurs in
seminiferous tubules
of the testes.
STE
PS
1.
Spermatocytogenesis
II. Meiosis (I and
II)
III.
Spermiogenesis

35. SPERMATOCYTOGENESIS
 Definition: The division of
spermatogonial cells to
produce spermatocytes.
 Types of Spermatogonia:
Type A (stem cells) and Type
B (progenitor cells).
 Type A spermatogonia
nourish themselves from
germinal cells and
differentiate into primary
spermatocytes.

36. MEIOSIS IN PRIMARY SPERMATOCYTES
 Definition: The first
meiotic division of
primary
spermatocytes.
 Reduces
chromosome number
from diploid (2n) to
haploid (n).
 Formation of
Secondary
Spermatocytes, which
are haploid and
contain 23

37. SPERMIOGENESIS
 Definition: The
transformation of
spermatids into mature
spermatozoa (sperm).
 Key Events: Formation of
acrosome, condensation
of nucleus, development
of the flagellum, and
reduction of cytoplasmic
contents.

38. SPERM STRUCTURE
 Description: A microscopic, tadpole-
shaped cell with distinct regions.
 Head: Contains the nucleus (haploid
chromosome set) and acrosome
(hydrolytic enzymes for fertilization).
 Neck: Holds a pair of centrioles that play
a role in zygote cleavage and form the
axial filament of the tail.
 Middle Piece: Enlarged with
mitochondria for ATP production,
providing energy for tail movement.
 Tail: Allows sperm motility, aiding in
reaching the egg for fertilization.

39. HORMONAL CONTROL OF SPERMATOGENESIS
STRUCTURE
 Initiation: Puberty triggers the release of
Gonadotropin Releasing Hormone
(GnRH) from the hypothalamus.
 Anterior pituitary releases two
gonadotropins: Luteinising Hormone
(LH) and Follicle Stimulating Hormone
(FSH).
 LH acts on Leydig cells to stimulate
androgen production, promoting
spermatogenesis.
 FSH acts on Sertoli cells, which secrete
inhibin to suppress FSH synthesis, and
also support spermiogenesis.

40. FEEDBACK MECHANISMS
Positive Feedback:
Hormones stimulate each
other, leading to significant
changes in hormone levels
during spermatogenesis.
Negative Feedback:
Hormones inhibit their own
production to maintain
hormonal balance.

41. CONCLUSION
Spermatogenesis is a
highly regulated process
crucial for male fertility.
Understanding these
mechanisms helps
appreciate the complexity
of human reproduction
and fertility.

42. INTRODUCTION:
 Oogenesis is the biological
process responsible for the
formation of mature female
gametes (eggs).
 It begins during embryonic
development and continues
throughout a woman's
reproductive life.
 The process involves the
transformation of primordial
germ cells into mature ova
capable of fertilization.

43. PRIMORDIAL GERM CELLS AND
OOGONIA:
During early embryonic
development, primordial
germ cells are specified.
These cells undergo
mitosis to form oogonia,
which are the progenitors
of oocytes.
Oogonia multiply rapidly
and form clusters called

44. FORMATION OF PRIMARY OOCYTES:
 The oogonia enter into
meiosis but arrest at prophase
of meiosis I before birth.
 Each primary oocyte is
surrounded by a layer of
granulosa cells, forming
primordial follicles.
 A female baby is born with all
the primary oocytes she will
ever have.

45. PUBERTY AND OVULATION:
 At puberty, a few primary
oocytes resume development
each month.
 This is initiated by hormonal
changes, particularly the rise
of FSH (follicle-stimulating
hormone).
 One primary oocyte is
selected from the pool and
matures into a secondary
oocyte.

46. MATURATION OF THE FOLLICLE:
 The selected primary oocyte
grows and is enclosed within a
developing follicle.
 The follicle consists of multiple
layers of granulosa cells and
an outer layer called the
theca.
 Theca cells secrete hormones
to support the oocyte's
development.

48. OVULATION:
 At the midpoint of the
menstrual cycle, the mature
follicle ruptures, releasing the
secondary oocyte.
 This process is called
ovulation and is triggered by a
surge in LH (luteinizing
hormone).
 The secondary oocyte is
released into the fallopian
tube, where it awaits
fertilization.
OVUM CHARACTERISTICS
 Human egg or ovum: Non-cleidoic,
alecithal, microscopic
 Formed as a result of oogenesis
from primitive germ cells
 Possesses inner plasma membrane,
middle glycoprotein zona pellucida,
and outer cellular corona radiata

50. FERTILIZATION AND FORMATION OF THE
OVUM:
 If the secondary oocyte is
fertilized by a sperm, it
completes meiosis II, forming
the ovum.
 The fertilized ovum travels
through the fallopian tube and
implants into the uterine lining.
 If fertilization does not occur,
the ovum degenerates,
leading to menstruation.

51. MENSTRUAL CYCLE PHASES:
 The menstrual cycle consists of
three phases: Menstrual,
Follicular, and Luteal phases.
 Menstrual Phase: Shedding of
the uterine lining, causing
menstruation.
 Follicular Phase: Growth and
maturation of the follicle, leading
to ovulation.
 Luteal Phase: Formation of the
corpus luteum, which produces
progesterone.

53. IMPORTANCE OF OOGENESIS:
Oogenesis is essential for
female fertility and
reproduction.
The production of mature
ova enables the potential
for pregnancy and
childbirth.
It plays a crucial role in the
continuation of the human

54. MENARCHE AND MENOPAUSE:
Menarche: First
menstrual flow, marks
onset of puberty (11-14
yrs)
Menopause: Natural
cessation of menstrual
cycle (45-50 yrs)
Hormonal control of
oogenesis: GnRH, LH,

55. ESTROUS CYCLE (OPTIONAL):
Cyclic changes in the
female reproductive
system of non-primate
mammals
Estrus: Period of heat,
increased estrogen level
Monoestrous (e.g., dog,
deer) or polyestrous
(e.g., mouse, cow) cycles

56. INTRODUCTION:
 Welcome to our comprehensive
presentation on fertilisation and
embryonic development.
 Fertilisation is the union of ovum and
sperm, resulting in the formation of a
diploid zygote, the first cell of a new
individual.
 Embryonic development involves a
series of crucial steps, including
cleavage, blastulation, implantation,
gastrulation, and organogenesis.
 Let's delve into the intricate processes
of fertilisation and the early stages of
embryonic growth.

57. FERTILISATION:
 Fertilisation occurs when
sperm are deposited into
the vagina during sexual
intercourse.
 The sperm swim through
the female genital tract
with the help of
prostaglandins present in
the semen.
 For successful
fertilisation, both the ovum
and sperm must reach the
ampullary isthmic junction
simultaneously.

58. STEPS OF FERTILISATION:
The haploid
nucleus of the
sperm fuses
with the
haploid ovum
nucleus to form
a diploid
zygote
containing 46
chromosomes.
Formation of
Zygote:
The entry of
sperm into the
ovum induces
completion of
meiosis-II,
forming a
haploid ovum.
Corticol and
Zona
Reaction:
Special
reactions occur
between the
sperm and egg
surfaces,
ensuring
compatibility
for fertilisation.
Fertilizin-
Antifertilizin
Reaction:
This involves
an acrosomal
reaction, where
enzymes are
released from
the sperm's
acrosome to
penetrate the
zona pellucida
of the ovum.
Penetration of
Sperm:
Spermatozoa
undergo a
process called
capacitation,
acquiring the
ability to
fertilise the
eggs.
Capacitation:
Male semen is
discharged into
the female's
vagina during
copulation,
allowing sperm
to swim in the
female
reproductive
tract.
Insemination:

59. CLEAVAGE:
 Cleavage starts about
30-36 hours after
fertilisation.
 The zygote divides by
mitosis into two smaller
cells called
blastomeres.
 Successive cleavages
result in the formation of
a solid ball of cells
known as the morula.
 The morula slowly
moves down the
Fallopian tube towards

60. IMPLANTATION:
 Implantation is the embedding of the
blastocyst into the uterine wall.
 Trophoblast cells produce lytic enzymes
that aid in blastocyst penetration into the
endometrium.
 The embryo is positioned with the inner
cell mass against the endometrium.
 Trophoblast cells form villi, which aid in
nutrient absorption and placental
development.
 Implantation triggers the secretion of
human Chorionic Gonadotropin (hCG),
the hormone used in pregnancy tests.

61. GASTRULATION AND ORGANOGENESIS:
 Gastrulation: A crucial stage
where the embryonic germ layers
(ectoderm, mesoderm, and
endoderm) are formed.
 Organogenesis: The process of
organ formation from the three
germ layers.
 These processes establish the
basic body plan and organ
structures of the developing

62. GASTRULATION:
Gastrulation is a vital process
during embryonic development
where cell movements
establish the three primary
germinal layers: ectoderm,
mesoderm, and endoderm.
These layers lay the
foundation for various organs
and tissues in the body. The
result of gastrulation is the
formation of a structure called

63. TYPES OF GASTRULAR MOVEMENT:
Gastrulation involves morphogenetic movements that shape the embryo.
These include:
1. Epiboly: Ectodermal cells envelop endodermal and mesodermal cells
(e.g., frog).
2. Emboly: Endodermal and chordamesodermal cells move inward (e.g.,
amphioxus).
3. Invagination: Endodermal cells sink in to form archenteron (e.g.,
amphioxus).
4. Involution: Chordamesodermal cells roll into ectodermal cells (e.g.,
frog).
5. Ingression: Blastomeres migrate into blastocoel to form solid gastrula
(e.g., Hydra).
6. Delamination: Blastoderm splits into two layers, forming hypoblast

64. FORMATION OF PRIMARY GERMINAL
LAYERS:
Gastrulation leads to the
creation of primary germinal
layers. The embryonal knob
rearranges to form an
embryonic disc. The outer
epiblast differentiates into
ectoderm and mesoderm,
while the inner hypoblast
becomes embryonic
endoderm. The ectoderm
forms both ectoderm and
mesoderm.

65. FOETAL MEMBRANES:
Foetal membranes are essential
for embryo development. They
include:
1. Amnion: A fluid-filled sac
protecting the embryo.
2. Allantois: A pouch facilitating
gas exchange and nutrient
transport.
3. Chorion: Envelopes the
embryo and aids in nutrient
and gas exchange.
4. Yolk Sac: Provides
nourishment and found in non-

66. ORGANOGENESIS:
Organogenesis is the
development and
differentiation of organs and
tissues. Notogenesis and
neurogenesis occur,
followed by the formation of
nervous and circulatory
systems. Most organs form
within a month of embryonic
development.

67. PLACENTA:
The placenta plays a crucial
role in nourishing the
embryo. It consists of foetal
and maternal parts,
allowing exchange of
nutrients, gases, and waste
products. There are various
types of placenta based on
structure and distribution of
villi.

68. PLACENTAL STRUCTURE:
The placenta as a two-part
masterpiece:
1. The foetal component,
called the chorion.
2. The maternal component,
termed the decidua
basalis.
In humans, the placenta earns
the title "chorioallantoic" as
both the chorion and allantois
contribute to its formation.

69. THE PLACENTA'S FUNCTIONS:
Picture the placenta as the embryo's guardian and lifeline. It's
responsible for several vital functions:
1. Nutrient Exchange: The placenta acts as a bustling
marketplace, transferring essential nutrients like glucose
and amino acids from the mother's blood to the foetus.
2. Waste Removal: Just as a cleaning crew, it ensures the
removal of waste products, including carbon dioxide and
urea, from the foetal bloodstream.
3. Hormone Production: But that's not all! The placenta also
moonlights as an endocrine gland, producing hormones like
hCG, progesterone, and oestrogens, supporting the
pregnancy journey.

70. DIVERSE PLACENTAL TYPES:
Placenta come in various structures based on attachment and
distribution:
1. Epitheliochorial Placenta: A strict six-barrier arrangement keeps
maternal and foetal blood separate (e.g., horse, ass).
2. Syndesmochorial Placenta: Uterine epithelium diminishes to five
barriers (e.g., cow, buffalo).
3. Endotheliochorial Placenta: With eroding epithelium and tissue,
it's down to four barriers (e.g., cat, dog).
4. Haemochorial Placenta: As the maternal part erodes, only three
barriers remain (e.g., humans, apes).
5. Haemoendothelial Placenta: Almost everything erodes, except

71. PLACENTA BANKING:
Placenta and umbilical cord
contain valuable stem cells
that can be stored in
placenta banks. These
stem cells have significant
therapeutic potential for
treating various diseases.
Placenta banking
harnesses this resource,
allowing for future medical

72. PREGNANCY AND PARTURITION:
Pregnancy is the
gestation period, lasting
about 280 days in
humans. Parturition, or
childbirth, is induced by
complex signals from the
fully developed foetus and
placenta. This leads to
contractions, followed by
the expulsion of the baby.

73. DILATION STAGE:
The uterine contraction
starts from top and occur at
long intervals. This forces
the baby, pushing its head
against cervix. As a result,
cervix gets dilated with
vagina also shows similar
dilation.
Dilation of cervix increases the stimulus for oxytocin secretion, further
increasing the strength and frequency of contractions (1-3 every
minute). With continued powerful contractions, the amnion ruptures
and the amniotic fluid flows out through the vagina.

74. LACTATION:
Lactation involves the
production and release
of milk after birth.
Colostrum, the initial
milk, is rich in proteins,
energy, and antibodies
for immunity. Milk
synthesis is driven by
the hormone prolactin.