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REPRODUCTION Reproduction is when organisms produce new individuals of the…
REPRODUCTION
Reproduction is when organisms produce new individuals of the same species
human reproduction
reproductive systems
MALE sex organs:testis
FEMALE sex organs:ovaries
human gametes/sex cells
male sperm
Produced from sex organ-testis
female egg
produced from sex organ-ovaries
types of reproduction
asexual
one parent
divide into 2 (for small organism)
e.g. bacteria
budding(part of body parts fall off and grow)
flowering plants
off spring look same as parent
sexual
2 parents
parents have sex organs to produce sex cells
off spring look different from parents
ovulation, fertilisation, implantation
ovulation
woman ovaries produce egg every 28 days
fertilisation
the fusing of nucleus of sperm and nucleus of egg
process
sperm swin from vagina>cervix>uterus
many sperm will die before reaching oviduct
if sperm meet egg=fertilisation occurs IN OVIDUCT
4.fertilised egg travel down oviduct>implant in uterus
acrosomal process (when sperm meets egg)
After fertilisation
zygote(fertilize egg) travel down oviduct>dividing by mitosis (cell dividing)>form embryo
embryo reaches uterus=implantation occurs
implantation
pregnancy stage when embryo stick onto uterus wall
to receive nutrient
after implantation
placenta, umbilical cord, amnion
and
amniotic fluid
form
embryo differentiates>produce variety of cells and tissues
embryo is called
foetus
when slightly look like a baby
Fetus growth and development
development
fetus has main human features
embryo become fetus in 8 weeks
continue develop for 40 weeks
necessities for fetus growth
protection from bumps
protection for temperature change
oxygen and nutrients
remove of waste substance
remove of waste substance
fetus protected by amniotic fluid and uterus
placenta
allows substance to diffuse from mom-->fetus
oxygen
glucose
diffuse substance from fetus-->mom
carbon dioxide
urea
adaptation (for diffusion)
large surface area between uterus wall
Villi (finger like projections that extend into the uterus wall)increase surface area
rich supply of maternal blood vessels
grows on wall of uterus
umbilical cord
joins fetus and placenta
umbilical artery
carries substance from foetus>mom
urea
carbon dioxide
umbilical vein
carries substance from mom>foetus
glucose
oxygen
Puberty
How does it happen
pituitary gland
secretes hormones into blood
Growth hormone-Increase in length and body size
Gonadotrophin-Stimulates the sex hormones
female sex hormones
produced in ovaries
Oestrogen
Progesterone
male sex hormones
produced in testis
Testosterone
located behind nose and beneath brain
start at 10-13 in girls 12-14 in boys
Menstrual cycle
prepare the thick uterus lining to receive fertilized egg
menstruation
egg not fertilized-->uterus lining break down
mom blood and fetus blood not joined but thin walls separated between them to allow diffusion
