HUMAN

REPRODUCTION

BY:M.SAIDI
ThunderEDU
C
By M.SAIDI
 INTRODUCTION
In the reproductive process, a
male sperm and a female egg
provide the information required
to produce another human being.
Conception occurs when these
cells join as the egg is fertilized.
Pregnancy begins once the
fertilized egg implants in the
uterus.
outline of the human life cycle to show the
role of meiosis, mitosis and fertilisation

The human body

constantly develops
and changes
throughout
the human life
cycle, and food
provides the fuel for
those changes.
Structure of the male reproductive
system
Bladder
Seminal vesicles
Ejaculatory ducts
Cowper's gland Prostate gland

Vas deferens Penis

Epididymis Urethra

Testis Fore skin

Scrotum

Clear view
 Functions of the parts
Seminal vesicles: produces a
nutrient rich fluid that that Prostate gland: Produces
provides an
energy for the sperm cells alkaline fluid that
neutralises the acids
Cowper's gland: Produces mucus produced in the vagina,
that helps with the movement of which would kill sperm
sperm cells cells
Vas deferens: Transports sperm
from the epididymis to the Urethra: Transports
urethra semen and urine out of the
body
Epididymis: stores Sperm cells
and allow the mature.
Urethra:Transports semen
and urine out of the body
Testis: Produces sperm cells and
the hormone testosterone
Scrotum: Skin sac that protects the
Question: Why do testes testes and holds the testes ‘outside’
hung outside the body? the body, at a temperature that is 2°C
below 37°C. This is the best
temperature for the production of
sperm.
 FUNCTIONS OF TESTOSTERONE
1. Development of male secondary sexual
characteristics, such as beard, pubic hair, deep
voice and a muscular body.
2. Stimulates the maturation of sperm cells.

Seminal vesicles, Prostate gland and Cowper's

gland are called accessory glands

By M.SAIDI
 Structure of seminiferous
tubes
Cells of Leydig
- Production of
Testosterone
Sertoli cells :-
- Provides nutrients
to developing
sperms
(spermatozoa)

By M.SAIDI
Structure of the female reproductive
system

Ovary

Fallopian tube
Endometrium
Uterus

Cervix

Vagina
Vulva

By M.SAIDI
 Functions of the parts
Ovary :Produces egg cells, Fallopian tube:
secretes progesterone and Connects the
oestrogen ovaries to the
Endometrium: uterus, transports
Inner lining of egg cells from the
uterus; place where ovary; it is the site
the embryo of fertilisation
implants and the
placenta forms Uterus: Carries the embryo
and foetus during
Cervix: Lower, narrow part
pregnancy
of uterus. It stretches to
allow the baby through Vagina: Receives the penis and
during childbirth semen during sexual
intercourse.
it is the passage through which
Vulva:external opening,
the baby is born (birth canal)
allows penetration to occur
STRUCTURE OF THE OVARY
Female sex organs.
Found in lower part of
abdominal cavity.
Made up of a covering
called germinal
epithelium with a
large number of follicles
in it.
Germinal epithelium
produces follicles.
This produces ova during
Oogenesis
Follicles secrete
oestrogen and
progesterone
 Puberty In males
Puberty is the period in humans in which
they experience physical changes in their
bodies in order to be capable of sexual
reproduction.
It’s a period which indicates sexual maturity
In boys, Stimulated by testosterone
the first puberty change is the
enlargement of the scrotum and testes.
As the testes and scrotum continue to
grow, the penis grows. (sex organs)
Growth of pubic hair, facial hair and
body hair
Development of muscles and
deepening of voice
 Puberty In females
Main changes that occur
under oestrogen
Growth of female sex
organs
Start of the menstrual cycle
production of ova
Growth of pubic hair
Growth and development of
breasts and widening of
hips
By M.SAIDI
 Formation of gametes
(gametogenesis)
❑ Gametogenesis is the formation of gametes
❑ During the process of gametogenesis, a germ
cell undergoes meiosis to produce haploid cells
that directly develop into gametes. Hence, in
animals, meiosis is an integral part
of gametogenesis.
❑ Its divided in two
Male gametes formed by spermatogenesis
Female gametes formed by oogenesis

By M.SAIDI
 Spermatogenesis:
∙ Spermatogenesis: this is the formation of
sperms
∙ PROCESS OF SPERMATOGENESIS.
Under the influence of testosterone
diploid cells in the seminiferous tubules
of the testes
undergo meiosis
to form haploid sperm cells
Germinal epithelium undergoes meiosis

Producing 4 haploid spermatids

Mature to form a spermatozoon

Each spermatozoon is made of a head,

middle portion and a tail.
 STRUCTURE OF A SPERM
The sperm cell is made up of:
1.Head which contains ACROSOME that contains the
enzymes to digest the membrane of ovum during
fertilization
The NUCLEUS which contain the genetic material for in
heritance
2.Middle piece with MITOCHONDRIA to provide energy
for sperm movement
3. Tail which provide propulsion force for sperm
movement
 OOGENESIS:
Oogenesis: is the formation of ovum

PROCESS OF OOGENESIS
Under the influence of FSH
diploid cells in the ovary undergo
mitosis
to form numerous follicles
One cell inside a follicle enlarges and
undergoes meiosis
Of the four cells that are produced, only
one
survives to form a mature, haploid
ovum

One cell inside a follicle

Meiosis

4 haploid cells formed

3 cells break up; one cell matures

Mature ovum
 STRUCTURE OF AN OVUM
Functions of the different Jelly-like layer

parts of an ovum Cytoplasm

layer of jelly- the provide
Nucleus
protection
Haploid nucleus-
contains genetic material Jelly-like layer
for inheritance
Cytoplasm
cytoplasm- its where
cells activities takes Nucleus

place and also contains

other parts of the cells
 MENSTRUAL CYCLE:
The menstrual cycle is divided into two
the uterine and ovarian cycles

ovarian cycles

uterine cycles
THE EVENTS IN THE OVARIAN CYCLE
These are events
that occur inside the
ovary only.
Development of the
Graafian follicle
under the influence
of FSH
Ovulation and
changing of empty
graafian follicle to
corpus luteum under
the influence of LH
THE EVENTS IN THE UTERINE CYCLE
Oestrogen stimulates the endometrium to
become thicker and develop more blood
vessels (vascular) and glands (glandular).
Under the influence of progesterone, the
endometrium to become even thicker and to
develop more blood vessels and glands, ready
to receive the embryo
if the level of progesterone drops , Lining
breaks down and is released (menstruation)
 Hormonal control of the menstrual cycle
Hormones from brain
F=FSH (hypophysis) L=LH MENSTRUAL CYCLE =FLOP
Stimulates the development
of Graafian follicle to • Trigger ovulation
1 3
Ovarian cycle =ovaries

produce ovum • Stimulates the conversion of empty

Graafian follicle to Corpus luteum

0 7 14 21 28
Hormones from ovary (G.F & CL) Maintains pregnancy
O=OESROGE P=PROGESTRONE by making
N Prepares the uterus for endometrium more
4
2 implantation ; by making it thick, more vascular &
thick, vascular & glandular more glandular
Uterine cycle =uterus

By M.SAIDI
ThunderEDUC
 SUMMARY
Day 1–7 •Day 14
Ovaries: New follicles •Ovaries: Graafian follicle
develop and secrete bursts to release an egg
oestrogen cell. The process is called
Uterus: Lining breaks down ovulation
and is released •Day 15–22
(menstruation) •Ovaries: The Graafian
Day 8–13 follicle becomes a corpus
Ovaries: Mature Graafian luteum that secretes
follicle develops and then progesterone
moves to edge of the ovary •Uterus: Progesterone
It secretes oestrogen. stimulates the
endometrium to become
Uterus: Oestrogen stimulates even more thicker and to
the endometrium to become develop more blood
thicker and develop more vessels and glands,
blood vessels and glands
•Day 23–28
•Ovaries:
•If fertilization does not take place:
•The corpus luteum shrinks
•stopping secreting progesterone (levels of
progesterone drop)
•Endometrium shrink
•Accompanied by bleeding
•If fertilisation takes place:
•The corpus luteum remains active in the
ovary
•and continues to secrete progesterone
•No more follicles develop in the ovaries
•No menstruation takes place
 Negative feedback
mechanism
Oestrogen inhibits FSH.
The follicle becomes the corpus luteum
and this produces oestrogen and progesterone
which inhibit FSH and LH production by the
pituitary.
This is an example of negative feedback .
Progesterone maintains the uterus lining (the
thickness of the uterus wall).
 COPULATION AND
FERTILIZATION
COPULATION:Is sexual activity typically
involving the insertion and thrusting of the penis
into the vagina for sexual pleasure/reproduction
purposes.

FERTILIZATION is when the haploid nucleus

of sperm fuses with haploid nucleus of ovum to
form a diploid zygote
PROCESS OF FERTILISATION
After ovulation, a haploid sperm cell
produces the enzymes from the acrosome
which digests the cell membrane of the ovum
and then sperm cell then penetrates the
haploid ovum.
The nuclei of the ovum and sperm fuse to
form a diploid zygote.
 DEVELOPMENT OF A ZYGOTE UNTIL
IMPLANTATION

By: M.SAIDI
Grade 12 life sciences ThunderEDUC
ThunderEDUC By: M.SAIDI
 How do we write in exams (most important)
morula
mitosis
mitosis
blastula

• After fertilization, the zygote undergoes

mitosis
• to form a ball of cells called morula
• it divides by mitosis repeatedly to form a
hollow ball of cells called blastula
chorion
• It forms the outer layer called chorion
• which form finger-like projects called chorionic villi
chorionic villi for implantation
By: M.SAIDI ThunderEDUC
 3D-ILLUSTRATION

By: M.SAIDI
ThunderEDUC
 1.4.The diagram below represents
Question a sequence of events that may
to try take place inside the human
female reproductive system.

By: M.SAIDI ThunderEDUC

 OVULATION TO EMBRYO DEVELOPMENT

3-D Qns
 DEFINITION OF
IMPLANTATION
IMPLANTATION: The attachment of
the fertilized egg to the uterine lining.
The embryo, moving as a blastocyst
through a uterus, makes contact with
the uterine wall and remains attached
to it until birth.
 The role of oestrogen and
progesterone in maintaining
pregnancy
Oestrogen and progesterone are the
chief pregnancy hormones.
A woman will produce more oestrogen during
one pregnancy than throughout her entire life
when not pregnant.
The increase in estrogen during pregnancy
enables the uterus and placenta to improve
vascularization (the formation of blood vessels)
Progesterone, will maintain what oestrogen has
built (maintaining the pregnancy).
 FUNCTIONS OF THE FOLLOWING
PARTS:
CHORION: to protect and nurture the embryo.
The chorionic fluid protects the embryo from shock.
CHORIONIC VILLI: allow the exchange of nutrients,
oxygen and waste products with the mother.
AMNION/ AMNIOTIC FLUID:
Has thin, transparent fluid in which the embryo is
suspended.
providing a cushion against mechanical injury.
Prevents dehydration of the baby.
Keeps the temperature almost constant.
Allow the developing baby to move in the womb.
Placenta: provides oxygen and nutrients to your
growing baby and removes waste products from your
baby's blood.
 Umbilical cord (including umbilical
artery and umbilical vein)
Umbilical cord It contains a vein, which
carries oxygenated, nutrient-rich blood to the
fetus,
and arteries that carry deoxygenated,
nutrient-depleted blood away.
 OTHER FUNCTIONS OF
PLACENTA
1. Nutrition: Nutrients diffuse from the maternal blood to
the foetus
2. protection; The placenta acts as a barrier or filter for
certain harmful pathogens and chemicals eg HIV and
alcohol.
3. Gaseous exchange, Oxygen and carbon dioxide are
exchanged between maternal and foetal blood
4. excretion, Nitrogenous wastes are carried away from
the foetus by maternal blood
5. endocrine function; After two months the placenta
takes over the secretion of progesterone and oestrogen
to maintain the endometrial lining.