Reproductive Systems
3-D male reproductive System
3-D female reproductive System
Testes Tissue
Sperm production occurs
in seminiferous
tubules
See Fig. 46.12
Testes Tissue
Sperm production occurs
in seminiferous
tubules
At puberty, testosterone
production begins
in interstitial cells
See Fig. 46.12
Testes Tissue
Sperm production occurs
in seminiferous
tubules
Sertoli cells regulate
sperm production &
nourish developing
sperm
See Fig. 46.12
Testes Tissue
Sperm production occurs
in seminiferous
tubules
Spermatozoa are
produced by
spermatogonia
See Fig. 46.12
Fig. 46.11
Animation: Spermatogenesis
Spermatogenesis
 production of sperms occurs in the
testes in seminiferous tubules
 first stage of spermatogenesis mitotic
cell divisions of primordial germ cells
to produce spermatogonial cells
 spermatogonial cells then undergo a
period of growth to form primary
spermatocytes
 each primary spermatocyte then
undergo two meiotic cell divisions:
 meiosis I to produce secondary
spermatocyte &
 meiosis II to produce spermatids
 spermatid cells then undergoes
differentiation to form sperm cells
 Sperm cells are nourished by Sertoli
cells
 each primary spermatocyte produce 4
sperm cells with haploid number of
chromosomes i.e. 23 chromosomes
Structure of the sperm
Animation: Oogenesis
Oogenesis
 oogenesis is process by which female gametes (egg
cells) are produced in the ovary
 it begins during fetal development when oogonia are
formed from primordial germ cells by mitosis
 Oogonia undergoes growth to form primary oocytes
 primary oocyte begin first meiotic division but stop
in Prophase I until on set of puberty
 at puberty some follicles develop each month in
response to FSH produced by pituitary gland
 primary oocyte completes first meiotic division to
forms two cells of different sizes due to unequal
distribution of cytoplasm
 the one with less cytoplasm become the first polar
body which eventually degenerates
 the larger cell becomes secondary oocyte and
proceeds to meiosis II & stops at prophase II
 meiosis II is completed if cell is fertilized forming an
ovum and second polar body
structure of the ovum
Animation: Comparison of Spermatogenesis and Oogenesis
Comparison Between spermatogenesis & oogenesis
spermatogenesis
 millions sperms produced per



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

day
four sperms of equal division
of the cytoplasm & no polar
bodies
begins at puberty i.e. at
sexual maturity
occurs throughout adult life
sperms are produced
continuously & released
during ejaculation
occurs in the testes
spermatogenesis involves
meiotic cell division
produce haploid cells
oogenesis
 one ovum per 28 day
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menstrual cycle
one ovum, unequal division
of the cytoplasm, 2 polar
bodies
begins during foetal
development
ends at menopause
ovum released during
ovulation in the middle of
the menstrual cycle
occurs in the ovaries
oogenesis involves meiotic
cell division
produce haploid cells
Fertilisation
 sperm cell approach the egg in oviduct
 Acrosome of sperm cell releases
hydrolytic enzymes which digest jelly
layer (zona pellucida) of the egg
 sperm cell head (acrosomal process)




extends through jelly to vitelline
membrane (egg’s plasma membrane)
binding proteins on surface of
acrosome attach to receptors on
vitelline membrane
sperm plasma membrane fuses with
egg plasma membrane
fusion of plasma membranes causes
depolarization of egg plasma
membrane i.e. cortical reaction which
bars other sperm cells from fusing
with membrane
sperm nucleus enters egg (secondary
oocyte) after dissolution of nuclear
membranes resulting in combination
of genetic material
Revision Questions
 Draw a labelled diagram of




the adult female reproductive
system.
[4]
Draw a labelled diagram of an
adult male reproductive
system.
[6 ]
Explain the processes
involved in oogenesis in
humans.
[9]
Draw the structure of a
mature human egg.
[4]
Explain the role of hormones
in the regulation of the
menstrual cycle in human
females.
[8]
 Draw a labelled diagram of a





mature sperm.
[5]
Outline the process of
spermatogenesis in humans.
[5]
Compare the process of
spermatogenesis and
oogenesis.
[7]
Describe the process of
fertilization in humans. [8]
Describe the development of
the early human embryo. [5]
Outline the regulation of
pregnancy by two named
hormones.
[4]