in this topic complete lecture about human reproduction on unacademy awesome

1. Ankit Mishra

5. Bladder
prostrate
Corpus spongiosum
Urethra
Penis glans
Seminal vesicle
Ejaculatory duct
Rectum
Anus

6. Ampulla
Seminal vesicle
Ejaculatory duct
Vas deferens
Epididymis
Testis
Urethra
Ureter
Urinary bladder
Prostrate
Bulbourethral gland
Corpus cavernosum
Corpus spongiosum
Glans of penis
Bulb
Crus

7. Testis
Seminiferous tubule
Epididymis
Vas deferens
Seminal vesical
Ejaculatory duct
Prostrate gland
Bulbourethral gland
Part Function
Testes Sexual organ produce sperm
Release male sex hormones androgen and testosterone,
Scrotum Sac which cover the testes and holds them out side the body
protection
Seminal
vesicles
Store sperm secrete fluid into sperm duct.
Fluids provide nutrients to the sperm
It also prevent the sperm from sticking together
Prostrate
gland
Secretes fluid into the semen. the fluid activates the sperm
Bulbourethr
al gland
Provide lubricants
Vas deferens Carry sperms from the testes to the urethra
urethra Help in ejaculation of sperm from the body to the female
vegina

8. Acrosome
Nucleus
Proximal Centriole
Mitochondria
Flagellum
Axial filament
Acrosome The acrosome is the product of Golgi complex and
contains a number of contents such as acrosin enzyme in the
acrosomal matrix. Apart from the enzymes, the acrosome also
contains such polysaccharides as mannose, hexosmine and galactose.
Nucleus 65 percent of the head and consists of 23 chromosomes.
Once the sperm cell enters the egg, the chromosomes combine with the
female gamete to make up 46 chromosomes -
Centriole In a complex referred to as the centriole-centrosome
complex, the centriole is involved in the formation of sperm aster
and zygote aster.
Mitochondria The midpiece of a sperm carries about 70
mitochondria, which is the source of energy (ATP). This provides
sufficient energy required for propulsion as the cell travels towards
the female gamete. The mitochondria of sperm cells is discarded
once the sperm head penetrates the egg.
Basic amines- The sperm contains a number of basic
amines such as cadaverine and spermine among others. These
amines are responsible for the alkaline (slightly basic) nature of
semen that protects the sperm. Given that the vaginal canal is
acidic, the amines protect the DNA from denaturation thus
promoting successful fertilization.

9. Haploid nucleus:
contain one copy of
each chromosome
mitochondria
Produce ATP used
for energy contain
mitochondrial DNA
Cortical granules
Release enzyme during
fertilization that harden the zona
pellucida and digest binding
protein prevent polyspermy after
a sperm cell has enter the ovum
Corona radiate
Protect the inner layer of
ovum and helps prevent
polyspermy
Zona pellucida/jelly coat
Contain glycoprotein that
protect inner content of
ovum until the acrosome
reaction of fertilization.
Cytoplasm

10. Primary
spermatocyte
Secondary
spermatocyte
Spermatids
Mature sperm cell
Meiosis first
Meiosis second
Multiplication
Growth phase
Maturation phase

11. Fundus
Fallopian tube
Uterine cavity
Endometrium
Vagina
Myometrium
Cervix
Uterus
Ovary
Carpus luteum
follicle

12. Ovary
Urinary bladder
Uterus
Pubic bones
Vagina
Cervix
Fallopian tube
Rectum
Clitoris

13. Carpus luteum
Mature follicleSecondary follicle
Primary follicle
Ovarian ligament
Carpus albicans
Ovulation
Structure of ovary

14. n
n
2n
n
n
2n
2n
2n
Oogonium
Primary oocytes
arrested in prophase I
Primary oocytes
Secondary oocytes
Primordial follicle
Primordial follicle
Growing follicle
Primary follicle
Mature follicle
Ovulation
Corpus luteum
Secondary oocytes , arrested
In metaphase II, ovulated
ZygoteSecond
polar body
First polar
body
Meiosis II
complete only
if fertilization

16. eaction
Sperm
nucleus
Sperm plasma
membrane
Hydrolytic enzymes
Cortical
granule
Cortical granule
membrane
EGG CYTOPLASM
Basal body
(centriole)
Sperm
head
Acrosomal
process
Actin
Acrosome
Jelly coat
Egg plasma
membrane
Vitelline layer
Fused plasma
membranes
Perivitelline
space
Fertilization
envelope
Cortical reaction. Fusion of the
gamete membranes triggers an
increase of Ca2+ in the egg’s
cytosol, causing cortical granules
in the egg to fuse with the plasma
membrane and discharge their
contents. This leads to swelling of the
perivitelline space, hardening of the
vitelline layer, and clipping of
sperm-binding receptors. The resulting
fertilization envelope is the slow block
to polyspermy.
5Contact and fusion of sperm
and egg membranes. A hole
is made in the vitelline layer,
allowing contact and fusion of
the gamete plasma membranes.
The membrane becomes
depolarized, resulting in the
fast block to polyspermy.
3Acrosomal reaction. Hydrolytic
enzymes released from the
acrosome make a hole in the
jelly coat, while growing actin
filaments form the acrosomal
process. This structure protrudes
from the sperm head and
penetrates the jelly coat, binding
to receptors in the egg cell
membrane that extend through
the vitelline layer.
21 Contact. The
sperm cell
contacts the
egg’s jelly coat,
triggering
exocytosis from the
sperm’s acrosome.
Sperm-binding
receptors
Entry of
sperm nucleus.
4

17. Types of Fertilization
Fertilization in Animals
The fertilization process in animals can occur either internally or externally, a difference
which is largely determined by the method of birth. Animals which
use viviparous and ovoviviparous reproduction (embryos develop within the animal’s
body), and oviparous animals which lay hard shelled eggs, use internal fertilization.

18. Animals which are oviparous, though produce eggs that are lacking, or have thin
egg membranes, reproduce by external fertilization. External fertilization is a
reproductive strategy involving the joining of gametes outside of the body, either in
a spawning event, where gametes from both sexes are rapidly released into an aquatic
environment, or may occur when eggs are laid by a female on a substrate, and are
subsequently fertilized by a male. External fertilization holds certain benefits, such as
reducing the chance of contracting sexually transmitted diseases, protection from violent
behavior between organisms, and increasing the genetic variation within a population
External fertilization

19. Internal fertilization involves the union of sperm and eggs within the body of the (usually
female) parent. In order for internal fertilization to occur, the male must implant his
sperm into the female reproductive tracts. Implantation can be achieved by either:
copulation, in which sperm transfer is performed by insertion of the penis or other
male intromittent organ and ejaculation into the vagina, or cloaca : or by a cloacal kiss,
in which two birds press their cloacae together and sperm transfer takes place. Some
animals, such as mollusks, arachnids, salamanders and certain insects, transfer
a spermatophore, a bundle or capsule containing sperm, which is stored within the
cloaca until oviposition takes place.

21. Gonadotropic
Hormone
cycle
Ovarian
Hormone
cycle
The menstrual cycle is a monthly
sequence of ovarian and uterine
events controlled by hormones
secreted by the pituitary gland
and the reproductive organs. The
average cycle length is 28 days.
During each cycle, an ovary
releases an oocyte and the uterus
is prepared for embryo
implantation. If fertilization does
not occur, a new menstrual cycle
begins. The menstrual cycle
consists of two phases: the
follicular phase and the luteal
phase. By convention, the cycle
begins with the onset of
menstruation-the shedding of the
endometrium, the mucous
membrane that lines the
uterus
Hormonal Control of the Menstrual Cycle
Follicular
phase
Luteal
phase

22. Gonadotropic
Hormone
cycle
Ovarian
Hormone
cycle
At the beginning of menstruation,
the pituitary gland releases high levels of
follicle-stimulating hormone (FSH) and
low levels of luteinizing hormone (LH).
FSH stimulates a follicle in the ovary to
grow. The developing follicle produces
low levels of estrogens and
progesterone. The low levels of
estrogens suppress LH secretion by the
pituitary gland through feedback
inhibition. Therefore, LH levels remain
low while estrogen levels are low. By day
7, menstruation is over, and the uterine
lining begins to rebuild itself. As the
follicle grows in the ovary, its production
of estrogen increases

23. Ovarian
Hormone
cycle
Gonadotropic
Hormone
cycle
As the level of estrogen increases, it
begins to exert positive feedback on
LH levels. That is, instead of
suppressing LH secretion by the
pituitary, estrogen now stimulates
LH secretion. The increased level of
estrogen triggers a large spike in LH
and a small spike in FSH that
together signal the end of the
follicular phase and the onset of the
luteal phase. The LH surge triggers
ovulation-the rupturing of the
follicle. This event occurs on or
around day 14

24. Gonadotropic
Hormone
cycle
Ovarian
Hormone
cycle
The secondary oocyte that
emerges from the ruptured follicle is
transported down the oviduct. In the
ovary, the corpus luteum develops
from the ruptured follicle.
The levels of estrogen, FSH, and
especially LH now drop appreciably.
But in response to the previous
surge in LH, the corpus luteum
begins to secrete large amounts of
progesterone and smaller quantities
of estrogen. In combination, these
hormones suppress the secretion of
FSH and LH from the pituitary gland
through feedback inhibition. With
FSH levels so low, no additional
follicles can mature during this part
of the menstrual cycle.

25. Gonadotropic
Hormone
cycle
Ovarian
Hormone
cycle
The rise in progesterone levels
converts the thickened uterine lining to
an actively secreting tissue with a well-
developed blood supply creating an
environment that will support
embryonic implantation and
development if fertilization occurs.
The corpus luteum remains active
during the first part of pregnancy and
keeps progesterone and estrogen levels
high.
When fertilization does not occur,
the corpus luteum degenerates.
Progesterone and estrogen levels fall as
a result, causing the thickened uterine
lining to degenerate as well.

26. Gonadotropic
Hormone
cycle
Ovarian
Hormone
cycle
With progesterone and
estrogen levels low,
feedback inhibition on LH
and FSH is removed. The
levels of LH and FSH begin
to rise. A new follicle then
starts to mature, and the
uterine lining starts to
slough off. A new
menstrual cycle begins.

28. Dilation
The first stage of parturition starts with the onset of labor. It continues until the cervix is fully
dilated. This dilation is divided into two phases:
•Latent phase. The cervix is 0 to 4 centimeters (cm) dilated.
•Active phase. The cervix is 4 to 10 cm dilated.
The latent phase takes about six hours for a woman who’s giving birth for the first time. It
takes around five hours for a woman who’s given birth previously. For some women, the
latent phase may last 8 to 12 hours.
During the active phase, it’s expected that the cervix will dilate at a rate of about 1 cm
per hour for a woman who’s giving birth for the first time. For a woman who’s previously
had a veginal delivary, the rate is typically about 2 cm per hour.

29. Early dilation
Baby head engaged widest
dimension is along left right axis
Late dilation
Baby head rotates so widest dimension is
in anteroposterior axis (of pelvic outlet).
Dilation nearly complete
Expulsion
Baby head extends as it is delivered
Placental stage
After baby is delivered the placenta
detaches and is removed

30. Expulsion
The second stage of parturition starts at full dilation and continues until birth. This stage also
has two phases:
•Passive phase. The baby’s head moves down through the vagina.
•Active phase. The mother feels a need to push, or contract the abdominal
muscles in time with uterine contraction.
The active phase lasts about 45 minutes for a woman who’s having her first baby.
For women who’ve had a vaginal delivery, the active phase lasts about 30 minutes.
Stage 2 ends with the birth of the baby. At this point, the umbilical cord is clamped,
and breast feeding is often encouraged to help with stage 3.

31. Placental
The third stage of parturition starts after birth and ends with the
delivery of the afterbirth (placenta and membranes).
If the doctor takes an active role — including gently pulling
on the placenta — stage 3 typically takes around five
minutes. If the placenta is delivered without assistance, stage
3 can last around 30 minutes.

33. The maturing follicle produces estrogen.
This causes the hypothalamus to send signals to the pituitary
gland to increase production of(LH) Lutenizing hormone.
Oestrogen also stimulates the female reproductive organs to
prepare for possible fertilization
OESTROGEN

34. • Responsible for all the Puberty changes such as Growth of Uterus,
Startification of vaginal epithelium, secretion and ciliary movement of
Fallopian tube etc. Responsible for the Proliferative stage of menstruation.
• Growth of Uterus during Pregnancy.
• Exerts synergistic action with Oxytocin.
• Oestrogens are responsible for the development of the female secondary
sexual characteristics that distinguish the Female from the Male.
• Effect on Bone growth. Breast development. External genitalia growth Fat
deposition. Increase protein anabolism. Decrease blood cholesterol.
Feminizes brain

35. PROGESTERONE HORMONE
Progesterone is a steroid hormone released by the corpus luteum that
stimulates the uterus to prepare for pregnancy. Progesterone is the
Active Principle of Corpus Luteum.
Sources: Corpus Luteum, Placenta, Adrenal Cortex. The synthesis of
Progesterone from Cholesterol by the placenta is important to the
maintenance of Human pregnancy after first trimester when ovarian
functions decline.

36. FUNCTIONS OF PROGESTERONE
• Progesterone is essential for the maintenance of pregnancy and
other changes associated with it. It also take part in Menstruation.
• Responsible for Premenstrual changes of Uterine Mucosa.
• Take an essential part in Pregnancy
• Embedding of Ovum: Progesterone secreted by the Corpus Luteum is
responsible for the premenstrual Hypertrophy of the Endometrium
which is essential for the reception and embedding of the fertilized
ovum

37. RELAXIN HORMONE
• Relaxin: A hormone that is produced during pregnancy that facilitates the
birth process.
• Relaxin also inhibits contractions of the uterus and may play a role in
determining the timing of delivery.
• Relaxin is a water-soluble polypeptide hormone present in pregnant
Mammalian ovary, placenta and uterus.
• Relaxin level of blood reaches maximum at the terminal stage of Pregnancy

38. FUNCTIONS OF RELAXIN
In females relaxin is produced mainly by the corpus luteum, in both pregnant and nonpregnant
females; it rises to a peak within approximately 14 days of ovulation, and then declines in the
absence of pregnancy, resulting in menstruation.
During the first trimester of pregnancy, levels rise and additional relaxin is produced by the
decidua.
Relaxin's peak is reached during the 14 weeks of the first trimester and at delivery.
It is known to mediate the hemodynamic changes that occur during pregnancy, such as
increased cardiac output, increased renal blood flow, and increased arterial compliance.
It also relaxes other pelvic ligaments. It is believed to soften the pubic symphysis.

40. Relaxin hormone secreted by the Ovary brings out the relaxation of the pelvic
ligaments and enlargement of Birth canal.
During pregnancy progesterone and oestrogen bring about the growth of
mammary glands.
Prolactin a hormone of Pituitary gland , influences the mammary glands to secrete
milk.
Before birth , there is no secretion of milk because Prolactin secretion is prevented
by Progesterone and Oestrogen.
During birth , there is a sudden drop in the production of these hormones and this
permits the onset of Lactation

41. Relaxin
Oestrogen
oxytosin
Prolactin
Enlargement
of birth canal
Contraction of
uterine muscles
Milk secretion
ROLE OF HORMONES IN PARTURITION

42. ROLE OF HORMONES IN PARTURITION
• Oestrogens stimulate the contration of the Uterine Muscles.
• Oxytocin secreted by the Pituitary gland accelerates the contraction of
Uterine muscles.
• It is released in large amounts after distension of the cervix and uterus during
labor, facilitating birth, maternal bonding, and, after stimulation of the
nipples.
• Oxytocin is also used in veterinary medicine to facilitate birth and to stimulate
milk release