Reproduction in Humans
Male Reproductive System
Objectives:
*Identify on diagrams the male reproductive
system and state their function
**Compare male and female gametes and their
production
Vsol: 1 a,b,d,e,I,j,k,4d
SCF: communication, Collaboration.
scrotum
Organ
Testes
Functions
Function
Scrotum
Produce spermatozoa and make male hormone
testosterone which stimulates changes during puberty
Sac covering testes which hangs outside the body to keep
it cool as sperm can’t develop or be stored at 37 0C or
above
Sperm duct
Small tubules outside the testes store sperms for
maturation. Sperm duct connect these tubules to urethra
urethra
Urethra carries urine and sperm but not at the same time.
A ring of muscle around the urethra contracts to prevent
urine loss during sexual intercourse
Prostate and other glands Secrete fluid for sperm cell to swim. Prostate secrete
mucus and other secrete sugar for respiration of sperm
cells. Sperm cell + fluid = semen
Penis
Urethra runs down the centre of penis. Its main function
is to deliver sperm to the vagina for fertilization
Gametes (sex cells)
Acrosome (contain enzymes to break the
jelly coat
Cell membrane
nucleus
Head
Middle piece (Has mitochondria to
power swimming by the tail)
Jelly coat
Egg cell
cytoplasm
Drives sperm
forward
Sperms and eggs are specialised. Which statements belong to a
sperm and which to eggs?
Compare
Feature
Sperm cell
Egg cell
Much larger
size
small
movement
Swim using tail that lashes
from side to side
Does not move itself .
Moved along oviduct by
cilia and peristalsis
food store
Has very little – uses sugar
in seminal fluid for
respiration
Protein and fat in
cytoplasm- enough to last
till implantation in uterus
no. of chromosomes
23 (haploid)
23 (haploid)
number produced
Millions produced
constantly after puberty
often throughout life
One a month after puberty
until menopause except
when pregnant or taking
contraceptive pills
Female Reproductive System
Objectives:
* Identify on diagrams the female reproductive
system and state their function
**Describe sexual intercourse in humans
Functions
Organ
Function
Ovaries(attached to
inside of abdomen just
below the kidneys
releasing 1 ova /28days
alternately
Produce ova and make female hormones progesterone
and oestrogen which stimulates changes during puberty.
Oestrogen- development of sex organs and sec. sexual
characteristics progesterone prepares uterus for receiving
the embryo in case of pregnancy
oviduct
The egg passes out to the funnel shaped opening of the
oviduct in a process called ovulation which then either
gets fertilised by a sperm or die after passing into the
uterus
Foetus develops here. It develops a spongy wall for
implantation of the embryo in case of pregnancy
A ring of muscles at the lower end of the uterus leading to
vagina
A muscular tube opening outside the body
Uterus
cervix
Vagina
urethra
A separate opening above the vaginal opening for urination
clitoris
Above urethra a very sensitive area (lot of nerves)
vulva
Outer opening of vagina
Word Check
18-9-16
Spermatogenesis
To be able to understand the process of sperm
production.
Standard: VSoL: 1 a,b,d,e,4 d
SCF: Communication , Collaboration, Critical Thinking
SPERMATOGENESIS
• Definition: It is the different steps by which
spermatogonia are transformed into
spermatozoa in the testis. It begins at puberty
(13-16 years) and continues into old age. The
whole process takes about 64 days.
Starter
• Review: Fill in the blanks.
• VSOL 4 d
• Competency -- communication & team work
Answers
•
•
•
•
•
•
•
•
•
•
•
Testes
Semen
Seminal vesicles
Bulbourethral glands
Prostrate glands
Urethra
Penis
Ovary/ovaries
Oviducts/fallopian tube
Uterus
fertilization
Site of sperm formation
Seminiferous tubules of Testis
MALE REPRODUCTIVE SYSTEM
 TESTIS
MALE REPRODUCTIVE SYSTEM
 TESTIS
EPIDIDYMIS
LOBULES
TUNICA
ALBUGINEA
TESTIS H&E
SEMINIFEROUS TUBULES
TESTIS H&E
SEMINIFEROUS TUBULES
SEMINIFEROUS TUBULES
INTERSTITIAL
CONN. TISSUE
TESTIS H&E
SEMINIFEROUS TUBULES
SEMINIFEROUS
TUBULES
INTERSTITIAL
CONN. TISSUE
MALE REPRODUCTIVE SYSTEM
MALE REPRODUCTIVE SYSTEM
 SPERMATOGENESIS
SPERMATOGONIA
1º SPERMATOCYTE
2º SPERMATOCYTE
SPERMATIDS
2º SPERMATOCYTE
1º SPERMATOCYTE
SERTOLI
CELLS
SPERMATOGONIA
SPERMATIDS
MALE REPRODUCTIVE SYSTEM
 SPERMIOGENESIS
Mature sperm 60µm long and acquire full motility in epididymis
(1) HEAD
- nucleus and acrosome
(2) NECK
- centriole and connecting piece
(3) TAIL
- middle piece
MALE REPRODUCTIVE SYSTEM  SPERMIOGENESIS
EPIDIDYMIS
EFFERENT DUCTULES
EFFERENT DUCTULES
EPIDIDYMIS
EFFERENT
DUCTULES
EPIDIDYMIS
EPIDIDYMIS
2n
spermatogonium
growth mitosis
primary
spermatocyte
Seminiferous
2n
tubules
Meiosis I
secondary n
n
spermatocyte
Meiosis II
spermatids n n
differentiation
(Sertoli cells
provide nutrients)
n n
sperm cells
(spermatozoa)
n
n
n
n
Cross-section of
seminiferous
tubules
Sertoli cell
nucleus
germinal
epithelium
Oogenesis (Intro’)
• Formation of eggs
• Outer layer of ovaries multiply to form
oogonia
• Oogonia grow and mature into oocytes
• Oocytes divide by meiosis to produce
haploid gametes
Oogenesis
• The process of egg formation
starts before birth
• The outer layer of the ovary, the
germinal epithelium, produces many
oogonia
• Oogonia grow to form
primary oocytes (2n)
• It also produces follicle
cells
• multiply and cluster
around the oocytes
• forming primary
follicles
primary follicle
secondary follicle
2n
n
Stages in the development of one follicle in a human ovary
Mitosis
Maturation Meiosis Growth
Male
Mitosis and
(spermatogenesis) cell division
Further
divisions
Spermatogonia
Many cells
Primary spermatocyte Growth
(2n)
Secondary
spermatocyte (n)
Spermatids (n)
Female (oogenesis)
Oogonia
Primary oocyte (2n)
of chromosome
DevelopmentHalving
of
follicle number from diploid (2n) to
haploid (n)
Released during
First polar body (n)
ovulation
fertilisationSecondary oocyte (n)
Second polar body (n)
First polar body (n)
Egg (n)
Sperm (n)
Gametogenesis in male and female
The primary oocyte continues the first
meiotic division leading to two unequal
daughter cells with 23 chromosomes each
(22 autosomes + X). The large cell is called
the secondary oocyte and the small one
(having little cytoplasm) is the first polar
body. The secondary oocyte and the first
polar body enter the second meiotic division
without DNA replication.
- The second meiotic division is completed
only if fertilization occurs to give fertilized
oocyte (mature ovum) and a second polar
body that soon degenerates.