• Embryology research. Researcher using forceps while preparing a specimen of a
mouse embryo during research on the embryology of the heart. The mouse embryo
has been prepared so that only the skeleton is left. Photographed at the IBDML, the
Developmental Biology Institute of Marseille-Luminy, France.
Structures that Support the Embryo
• Structures that Support the Embryo
• Label the diagram below and describe
what each part contributes.
• Amnion: transparent sac
• Yolk Sac:
• Allantois:
• Chorion:
Structures that Support the Embryo
• Structures that Support the Embryo
• Label the diagram below and describe
what each part contributes.
• Amnion: transparent sac, protection,
contains amniotic fluid
• Yolk Sac: sac suspended from
abdominal area of embryo, first blood
cells, digestive tract, eggs or sperm
• Allantois: becomes umbilical chord,
bladder
• Chorion: forms fetal portion of placenta
Structures that Support the Embryo
• Placenta
• The placenta is a disk shaped organ
within the uterus that is rich is blood
vessels; it attaches the embryo or fetus
to the uterine wall. List some of the
many functions of the placenta:
• * Fetal and maternal blood does not
mix!
• The umbilical cord connects the
placenta to the fetus (at its belly button).
• Provides nutrients and oxygen to
embryo
Structures that Support the Embryo
• Fetal and maternal blood
does not mix!
• Umbelical cord and
placenta? Which is
which?
Fetal Development and Birth
8 Weeks
• Hormonal Changes
• The thickened endometrium is
maintained by the release of
progesterone from the corpus luteum.
(1-2 months)
• The corpus luteum is maintained by a
hormone released from the developing
placenta called HCG: (Human Chorionic
Gonadotropin)
• After approximately 2 months, the
placenta decreases HCG production and
increases progesterone and estrogen
production.
• The placenta takes on the hormonal
function of the corpus luteum to
maintain the pregnancy
Some Vids
• Conception to Birth
• Reabsorbing Fetuses
Fetal Development and Birth
8 Weeks
• Pregnancy Stages
(3 month stages)
• 1st Trimester (3 months):
• Placenta develops
• Major organ systems develop
• Bones and muscles develop
Kirkup’s “Alien” at 8 Weeks
• Foetus. Coloured scanning electron micrograph (SEM) of an eight week old human foetus. The
foetus' eye, nose and hands are visible. The eighth week of pregnancy represents the end of
the formative developmental stage, and the embryo becomes a foetus. It is human-like in
appearance, with the head large in proportion to the body. All major organ systems are formed
by the eighth week, but require much growth since the foetus is only about 3 centimetres in
crown-rump length. Magnification: x12 when printed 10 centimetres wide.
Fetal Development and Birth
•
•
•
•
2nd Trimester: 8 Weeks
Activity begins (kicking)
Hair develops
Systems nearly completed
• Premature babies may survive if born
after the 2nd trimester.
Fetal Development and Birth
8 Weeks
•
•
•
•
3rd Trimester:
Final rapid growth
Fat develops
Eyelids open and ears become
functional
Crazy Fetuses
What is it?
Homer
Simpson!!!
Batman!
Blind
mouse!
Here kitty
Kitty!
Sonic the
Hedge
Hog!!!
A cyclops! It’s a
doggy! Suffering
from cyclopia
MRI 36 Weeks
Fetal Development and Birth
• Fetal Alcohol Spectrum Disorder (FASD) - Video
• Physical defects: Lower birth weight, congenital heart defects,
CNS abnormalities.
• Behavioural defects: Inattentive, hyperactive, lower IQ,
depression, poor social skills.
• What amount of alcohol is suggested? NONE – while trying to get
pregnant, pregnant and breast feeding
• Other teratogens include: some antibiotics, acne medications,
anti-thyroid drugs, anti-cancer drugs, thalidomide, radiation, XRays, PCBS, mercury, etc.
Fetal Development and Birth
• Other teratogens include: some antibiotics, acne medications,
anti-thyroid drugs, anti-cancer drugs, thalidomide, radiation,
X-Rays, PCBS, mercury, etc.
Caption: Thalidomide child. Toddler with a
deformed foot that has an extra appendage on
its left side. This birth defect resulted from the
drug thalidomide. This was prescribed in the
late 1950s and early 1960s as an anti-nausea
medication and sleep aid for pregnant mothers
with morning sickness. The child also has
phocomelia, a deformity where the hands have
developed on stunted arms (just visible at
lower left). After several babies were born with
phocomelia and similar birth defects,
thalidomide was revealed as a terotogen
(causes developmental deformities) and was
banned worldwide in 1962.
What hurts more?
Birth or a kick in the balls?
Birth-- Parturition