UNIT 17: REPRODUCTION IN HUMANS
Ovary: makes female gametes (eggs)
Uterus: thick walls of muscles, small but can stretch
greatly
Oviduct: tube leading from ovary to uterus, fertilisation
here
Cervix: uterus’ guard muscle, supply mucus to vagina
Vagina: receive the penis, muscular and stretchable
Adaptive features of the egg cell:
Jelly coat + membrane: protection to the ovum as it
passes down the oviduct and then barrier to the entry of sperms after
fertilisation
Energy stored within small amounts of fat and protein in
yolk of cytoplasm to nourish the cells
Testis: makes male gametes (sperms), held outside by
scrotum
o Made of millions of tiny coiled tube
o Works efficient below body temperature -> held
outside of body
Urethra: carries urine and sperms to outside
Prostate gland: makes semen; provide nutrients for
sperm to swim
Sperm duct: carry sperms away from testes
Penis: introduce sperms into female, contain spongy tissue that are filled with
blood
o Tail (flagellum): produces swimming movements
o Mitochondria: in middle piece, release energy by aerobic respiration for
swimming
o Acrosome: vesicle contain enzymes to dissolve a way through jelly coat of
egg cell
Male gamete Female gamete
Released in millions Released one at a time
Able to move Unable to move on their own
Very small Comparatively large
Very little cytoplasm A lot of yolky cytoplasm
1. Ovulation: a mature follicle bursts and releases an egg into the oviduct
2. Fertilisation. Fusion of the nuclei from a male gamete (sperm) and a female
gamete (egg cell)
o During sexual intercourse, erect penis is inserted into vagina
o Semen is ejaculated into the neck of the vagina
o Many sperms cluster around ovum but only one sperm’s head penetrates
o Egg membrane becomes impenetrable -> other sperms die
, UNIT 17: REPRODUCTION IN HUMANS
3. Zygote divides and after hours, a ball of cells is formed which keep dividing into
embryo in oviduct
4. Implantation: Movement of a young embryo into lining of the uterus and
attachment there
o Umbilical cord: link embryo to placenta, contain blood vessels
o Placenta: in mammals, organ made up of tissues of mother and embryo,
where their bodies exchange substances by diffusion; Have villi which fit
closely into uterus wall
Help in exchange of dissolved nutrients, gases and excretory products and
providing a barrier to toxins and pathogens
o Amniotic sac: enclosing fetus, secret amniotic
fluid and prevent entry of bacteria
o Amniotic fluid: secreted by amnion, supports,
protects fetus by keeping pressure constant,
allow it to move
Some toxins (nicotine) and pathogens (rubella virus)
can pass across placenta and affect fetus
Development of the embryo and fetus
6 weeks: major organs begin to grow
8 weeks: embryo is 1.5 cm long, has muscles and start moving
10-11 weeks: all organs are in place, embryo is now a fetus
38 weeks: fetus is ready to be born
Nutrie Function
nts
Calciu Form fetus’s bones
m
Iron Produce extra blood to carry
substances to placenta; make
baby’s haemoglobin
Carbs Extra energy to move heavier
body
Protei Form fetus’s new cell
n
Ante-natal care
Take regular exercise
Avoid smoking – harmful substances can be transferred and affect
development
Avoid alcohol – baby can be born with developmental problems
Breast-feeding Bottle feeding
Contains antibodies to fight disease Mother can hand over baby to
Builds a close mother-baby someone else
Ovary: makes female gametes (eggs)
Uterus: thick walls of muscles, small but can stretch
greatly
Oviduct: tube leading from ovary to uterus, fertilisation
here
Cervix: uterus’ guard muscle, supply mucus to vagina
Vagina: receive the penis, muscular and stretchable
Adaptive features of the egg cell:
Jelly coat + membrane: protection to the ovum as it
passes down the oviduct and then barrier to the entry of sperms after
fertilisation
Energy stored within small amounts of fat and protein in
yolk of cytoplasm to nourish the cells
Testis: makes male gametes (sperms), held outside by
scrotum
o Made of millions of tiny coiled tube
o Works efficient below body temperature -> held
outside of body
Urethra: carries urine and sperms to outside
Prostate gland: makes semen; provide nutrients for
sperm to swim
Sperm duct: carry sperms away from testes
Penis: introduce sperms into female, contain spongy tissue that are filled with
blood
o Tail (flagellum): produces swimming movements
o Mitochondria: in middle piece, release energy by aerobic respiration for
swimming
o Acrosome: vesicle contain enzymes to dissolve a way through jelly coat of
egg cell
Male gamete Female gamete
Released in millions Released one at a time
Able to move Unable to move on their own
Very small Comparatively large
Very little cytoplasm A lot of yolky cytoplasm
1. Ovulation: a mature follicle bursts and releases an egg into the oviduct
2. Fertilisation. Fusion of the nuclei from a male gamete (sperm) and a female
gamete (egg cell)
o During sexual intercourse, erect penis is inserted into vagina
o Semen is ejaculated into the neck of the vagina
o Many sperms cluster around ovum but only one sperm’s head penetrates
o Egg membrane becomes impenetrable -> other sperms die
, UNIT 17: REPRODUCTION IN HUMANS
3. Zygote divides and after hours, a ball of cells is formed which keep dividing into
embryo in oviduct
4. Implantation: Movement of a young embryo into lining of the uterus and
attachment there
o Umbilical cord: link embryo to placenta, contain blood vessels
o Placenta: in mammals, organ made up of tissues of mother and embryo,
where their bodies exchange substances by diffusion; Have villi which fit
closely into uterus wall
Help in exchange of dissolved nutrients, gases and excretory products and
providing a barrier to toxins and pathogens
o Amniotic sac: enclosing fetus, secret amniotic
fluid and prevent entry of bacteria
o Amniotic fluid: secreted by amnion, supports,
protects fetus by keeping pressure constant,
allow it to move
Some toxins (nicotine) and pathogens (rubella virus)
can pass across placenta and affect fetus
Development of the embryo and fetus
6 weeks: major organs begin to grow
8 weeks: embryo is 1.5 cm long, has muscles and start moving
10-11 weeks: all organs are in place, embryo is now a fetus
38 weeks: fetus is ready to be born
Nutrie Function
nts
Calciu Form fetus’s bones
m
Iron Produce extra blood to carry
substances to placenta; make
baby’s haemoglobin
Carbs Extra energy to move heavier
body
Protei Form fetus’s new cell
n
Ante-natal care
Take regular exercise
Avoid smoking – harmful substances can be transferred and affect
development
Avoid alcohol – baby can be born with developmental problems
Breast-feeding Bottle feeding
Contains antibodies to fight disease Mother can hand over baby to
Builds a close mother-baby someone else
