Transcript The Development of the Embryo through to New Born

The Development of the Embryo
through to Birth
Unit 4
Conception
• How does conception happen?
• http://www.youtube.com/watch?v=9CO5Nl_ngCo
The sperm approaching the egg
• Sperm & egg join in the
fallopian tube
• 46 chromosomes
combine, which predetermine all of a
person’s physical
characteristics
Fertilized Ovum
• 30 hours after
conception
• No larger than a pin
head
• Rapidly dividing
• The fertilized Ovum is
called a Zygote
• Floats down from the
fallopian tube towards
the uterus
3 Weeks
• Once in the Uterus, the developing embryo, called a
Blastocyst, searches for a nice place to implant
• It actually burrows beneath the surface of the uterus
• The yolk sac produces blood cells during the early
weeks of life
• It is only one sixth of an inch long
• The backbone, spinal column, and nervous system
are forming.
• The kidneys, liver and intestines are taking shape
4 Weeks
• The embryo produces
hormones which stop
the mother’s menstrual
cycle
5 Weeks
• Embryo is size of a raisin
• Day 21 – the heart has begun beating
• Neural tube enlarges into 3 parts, soon to become a
very complex brain
• The placenta begins functioning
• The spine and spinal cord grows faster than the rest
of the body and gives the appearance of a tail.
• http://pregnancy.about.com/od/pregnancycalendar/
ig/Early-Ultrasound-Photos/
6 & 7 Weeks
• 7 weeks – facial features are
visible, including a mouth &
tongue
• The eyes have a retina & lens
• The major muscle system is
developed
• The embryo practices moving
and has its own blood type
• The blood cells are produced
by the liver now instead of the
yolk sac
• http://pregnancy.about.com/o
d/pregnancycalendar/ig/6Weeks-Pregnant.-Tgk/
8 Weeks
• Embryo now called a foetus
• Is about half an inch long
• Is protected by the amnionic
sac, filled with fluid
• The foetus swims and moves
gracefully
• Arms & legs have lengthened
• Fingers can be seen
• Toes will develop in the next
few days
• Brain waves can be measured
• http://pregnancy.about.com/
od/pregnancycalendar/ig/8Week-Ultrasound-Photos/
10 Weeks
• Heart is almost completely developed and very much
resembles that of a newborn baby
• The blood is diverted away from the lungs by an
opening of the atrium of the heart and the presence
of a bypass valve
• The blood is oxygenated through the placenta
• 20 tiny baby teeth are forming in the gums
• http://pregnancy.about.com/od/pregnancycalendar/
ig/10-Week-Ultrasound-Photos/
12 Weeks
• Vocal chords are complete
• Can and does sometimes
cry (silently)
• Brain is fully formed
• Can feel pain
• May suck his/her thumb
• Eyelids now cover the eyes,
and remain shut until the
7th month to protect the
delicate optical nerve fibres
14 Weeks
• Muscles lengthen and
become organised
• Mother will soon start
feeling first flutters of
the feotus kicking and
moving
15 & 16 Weeks
• 15 weeks – The feotus has an adults taste buds and
may be able to savour the mother’s meals
• 16 weeks – 5 and a half inches tall
• 6 ounces in weight
• Eyebrows, eyelashes and fine hair appear
• The foetus can grasp with his/her hands, kick, or
even somersault
• http://pregnancy.about.com/od/pregnancycalendar/
ig/16-Week-Ultrasound-Photos/
20 Weeks
• 20 weeks – can hear &
recognise mother’s voice
• Still small & fragile but
growing rapidly
• Could possibly survive if born
• Finger nails and finger prints
appear
• Sex organs are visible
• What happens during an ultra
sound?
• http://video.about.com/preg
nancy/Ultrasound.htm
• Ultrasound device can tell if
girl or boy and pick up certain
abnormalities such as Spina
Bifida, Cleft Lip/Palate etc.
24 Weeks
• Covered with a fine downy
hair called Lanugo
• Tender skin is protected by a
waxy substance called vernix
• At birth- substance may still
be on the skin but it will be
quickly absorbed
• Breathing is practiced by
inhaling amnionic fluid into
developing lungs
• http://pregnancy.about.com/o
d/pregnancycalendar/ig/24Week-Ultrasound-Photos/
30 Weeks
• The umbilical cord has been
the lifeline to the mother
• Nourishment is transferred
from the mother’s blood,
through the placenta, and into
the umbilical cord to the
feotus
• If mother ingests toxic
substances i.e. alcohol/drugs,
the baby receives these as
well
• http://pregnancy.about.com/o
d/pregnancycalendar/ig/30Week-Ultrasound-Photos/
32 & 36 Weeks
• 32 weeks – The foetus
sleeps 90-95% of the day
• Sometimes experiences
REM sleep, an indication of
dreaming
• Summary - Ultrasounds
week by week
• http://www.youtube.com/w
atch?v=gfgq7WiHbh4
40 Weeks
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Now approx 7 & a half pounds
Is ready for life outside its womb
Vaginal Delivery:
http://video.about.com/pregnancy/Delivery.
htm
Caesarean
http://video.about.com/pregnancy/Cesarea
n-Section.htm
Real Life C-Section
http://www.babycenter.ca/video/pregnancy
/c-section/
http://www.mayoclinic.com/health/csection/MM00531
At birth the placenta will detach from the
side of the uterus.
Umbilical cord will cease working as the first
breaths are taken.
Child’s breathing will trigger changes in the
structure of the heart and bypass arteries
which will force all blood to now travel
through the lungs.