In recent decades, it’s become possible
to carry out in vitro fertilization as part
of the process of assisted reproduction. Here,
a larger number of the normal eggs are induced
to form in the mother and to mature, whereupon,
they are harvested and taken to a Petri dish.
The sperm is then added to the Petri dish
and the embryos are carefully observed.
Those which are fertilized and continue to
develop normally can be returned to the uterus.
Normally, these days, it’s normal to return
just one of the fertilized eggs.
Otherwise, there is a risk of twin pregnancies developing.
Spare embryos can be frozen for a subsequent
attempt, or sometimes for other research purposes.
In this image, we see pipet on the left-hand
side of the picture through which a gentle
suction is holding an egg against the prepared
tip and on the other side of the image, we
can see an even finer pipet which is about
to inject the sperm not just through the corona
and zona, but also through the plasma membrane
of the cell itself. So that particular sperm,
which may come from an adult donor whose sperm
is in some way incapable of normal fertilization,
can be placed directly in the cytoplasm of
the egg, and therefore, lead to fertilization
and development in couples who otherwise would
be unable to have children. So this is one
of the most dramatic interventions that can
take place during the course of assisted reproduction.
So, let’s look in summary of what we’ve
covered in this lecture. First, we looked
at the origin of the primary germ cells and
their migration towards the gonad. Then we
looked separately at oogenesis in the female,
and spermatogenesis in the male. We brought
together these products of the process of
gametogenesis in fertilization. And then we
followed the transport of the fertilized egg
down the oviduct to finally implant in the
uterus. Last of all, we looked at some assisted
reproductive techniques, including in vitro
fertilization. Thank you very much.