Fertilization (Conception)
- DNA from the father's sperm combines with
DNA from the mother's ova. The pre-embryo is already genetically male or
female, and a completely unique individual. (11.)
- The single-celled fertilized begins growing by dividing into two
cells. One of these cells will form the embryo's body and internal organs. The
other cell will form the external organs that the embryo will need to survive
in the womb; the amniotic sac and chorion (the blood vessels that will later
make up the placenta). (4.)
.
6 to 9 Days
- The pre-embryo implants in his or her mother's uterus. (11.)
.
2 Weeks
- The embryo grows his or her first brain cells. (11.)
- The embryo's body is divided into three layers. The outer layer of
cells in called the ectoderm, and will develop into the outer layer of the skin
and the nervous system. The middle cells, or mesoderm, develops blood, bone,
cartilage, and muscle. The endoderm, the inner layer, develops eventually into
mucus membranes and glands. (8.)
.
3 Weeks
- The embryo's heart is beating, though it has only one chamber.
Throughout his or her development, the embryo's body is fully functional,
though the organs are still developing and incomplete. (1.)
- The embryo has a separate brain and spine. His or her brain is
divided in three segments; the forebrain, midbrain, and hindbrain. (7.,12.)
- The placenta is forming. Blood vessels have formed in the chorion,
the outer sac surrounding the embryo, and are insinuating themselves into the
lining of the mother's uterus. Once enough of these connections have been made,
and the embryo's circulatory system is sufficiently operational, exchange of
nutrients and oxygen will begin between mother and child. (5.)
- Limb buds, the beginnings of arms and legs, are forming. (6.)
.
4 Weeks
- Circulation to and from the placenta begins. (11.)
The placenta is an organ unique to gestating mammals, and it is truly
amazing in its versatility. It is so important to the embryo that it was being
prepared almost as soon as he or she was conceived. (4.) The placenta works
like a born individual's lungs, digestive system, and kidneys work, all at
once. (5.) The mother's body shelters her embryo, and her blood makes nutrients
and oxygen available to him or her, but the mother's blood and the baby's can
never mix. (11.) So the mother's lungs, her digestive system, and her kidneys
can't take care of the embryo's body -- he or she has to do that independently
through the embryonic half of the placenta, the chorion.
The chorion connects to the mother's uterus, and filters oxygen out
of her blood into the baby's, just the way a born individual's lungs take
oxygen out of the air and into his or her blood. It also gathers nutrition for
the embryo, the same way a born individual's digestive system gathers nutrition
from the food he or she eats. And
lastly, the embryonic half of the placenta sifts
waste out of the embryo's blood, like a born individual's kidneys take waste
out of his or her blood (5., 11.). Soon the embryo's own kidneys will begin to
function, and share this work with the placenta. (3.)
You should be aware that some sources consider the placenta to be a
"materno-fetal" organ, made up of both maternal and fetal tissues. This is
accurate as far as it goes, but can be misleading. Blood vessels from the
chorion do entwine with blood vessels in endometrium, the lining of the
mother's uterus, and both of these are essential to the embryo's survival. The
combined endometrium and chorion make up the placenta. Both the chorionic blood
vessels and the maternal blood vessels (endometrium) are passed out of the
woman's body at birth.
However, the woman's tissues play no active part in maintaining the
embryo - they are simply there and accessible to him or her. The chorion - the
embryonic half of the placenta - is the active, life-sustaining half of the
placenta. The term 'materno-fetal' accurately describes the placenta in that it
serves as a junction between two
unique circulatory systems; however, it
should not be used to imply that the placenta is not the embryo's organ, or
that the embryo is not biologically self-sufficient.
- The embryo has hands with ridges that will grow into fingers, and
two-segmented arms. (6.)
- The embryo has feet, thighs, and calves. (6.)
- Internal organs are growing. The tongue, esophagus and stomach are
well developed, as are the kidneys. The embryo's liver, gall bladder, and
pancreas have been developing for several days. Lungs begin to develop. His or
her thyroid and other glands are forming. (13.)
- The embryo's face and sensory organs are forming. He or she has eyes,
including a retina that already has color (3.), as well as ears, a nose, and
mouth. (3., 6., 11.)
- Reproductive organs are beginning to form. (11.)
.
5 Weeks
- The brain divides into more specialized segments. The forebrain
develops into two distinct sections, called the telencephalon and the
diencephalon. The telecephalon is the primitive cerebrum, the 'thinking' part
of the brain. The cerebrum is responsible for sensory perception, memory,
learning, and conscious thought. The diecephalon develops into the thalumus and
the hypothalumus, the 'feeling' part of the brain. The thalamus serves as a
relay station between the senses and the brain. The hypothalamus produces basic
drives and emotions such as hunger, thirst, pleasure, and fear. The midbrain
continues to develop into brain structures also necessary for processing
sensory information, while the hindbrain grows towards becoming the cerebellum,
medula, and pons. These parts of the brain are responsible for unconscious
physical processes like blood circulation or breathing, as well as reflexes.
Also, the structures of the hindbrain are necessary for muscle coordination and
movement. (10.)
- At 40 days, about five days after he or she turned 5 weeks old, the
embryo's brain waves can be detected by an electroencephalogram. (9.)
You may hear this disputed by pro-choicers; that
these are not organized brain waves and thus should not be called brain waves
at all, they are not from the higher brain structures, they are not indicative
of true brain function, of thought, of awareness. All of these facts are
disputed not just in the abortion debate, but in medicine in general. An honest
answer to the question "Does the embryo think?" is simply "We don't know."
There is ample reason to think that he or she does, however. The embryonic body
is not built like a automobile or baked like a cake; it is a living being and
it grows like one. Unlike human creations, nature's unfinished specimens are
not piles of useless parts. All the parts of a healthy living thing are, at all
times, functional to some degree. Nothing just sits there - life requires
motion, action, usefulness. At no time does the embryo have a nonfunctional
brain (or any other organ). It has a brain that is functional to the degree it
is developed. Of course that brain cannot perform all the functions of an adult
brain; but it is not just sitting there. It is working, in all its parts,
including those parts that exist entirely so as to make us human beings
conscious, aware, willful creatures.
- The embryo has a palate (inside of the mouth and tongue), completely
with tiny tooth buds (13.)
- His or her face is nearly finished forming and looks reasonably
human, though lacking the muscles needed for facial expressions like smiling or
frowning. (11., 13.)
- The embryo begins to move. These early movements are important to the
development of healthy muscles. (3.)
.
6 Weeks
- Dr. Harley Smyth, a neurologist, testified before the Canadian
Supreme Court that "at 6 weeks there is the possibility of recording electrical
activity from the nervous system already so highly organized that it can
subserve . . . purposeful and even co-ordinated movements." (2.)
- The embryo looks like a baby in miniature, though his or her head is
still very large compared to the rest of the body, because the brain is growing
so quickly. (11.)
- The embryo's face and lips are sensitive to touch. (1.)
- The embryo has distinct fingers. (3.)
.
7 Weeks
- All the embryo's organs and organ systems have been developed, though
they are still immature and need time to finish growing. Several organ systems,
including the circulatory system (heart), are already almost fully functional.
(13.)
- The embryo has distinct toes. (11.)
.
8 Weeks
- The unborn baby is now called a 'fetus', because he or she has
finished with the process of organogenesis (the creation of new organs). (11.)
Fetus means "young one" in Latin. (3.)
- The fetus's genital area is sensitive to touch. (1.)
- Eyelids begin to form. (11.)
.
9 to 10 Weeks
- The fetus touches his or her own face and sucks his or her thumb, and
makes breathing and swallowing motions. (3.)
- The palms of the fetus's hands and the soles of his or her feet are
sensitive to touch. (1.)
- The sense of smell begins to develop. (1.)
- The fetus urinates and experiences hiccups. (3.)
- He or she is moving almost constantly, and can step, kick,
somersault, stretch, and move his or her arms. (3.)
.
11 to 13 Weeks
- The fetus's bone marrow begins to produce white blood cells. (11.)
- The fetus's external reproductive organs are visibly male or female;
prior to stage of development, though the embryo was male or female, the penis
and clitoris looked too similar to tell apart at a glance. (3.)
- The inner parts of the ear are formed, and the fetus may be able to
hear. (3.)
- The bones undergo "ossification" -- they become hard, like an adults
bones, whereas they had previously been soft. (11.) · The sense of taste
develops. (1.)
- The fetus's face continues to mature, and by the end of the 3rd
month, each baby has unique, individual facial features. (3.)
.
14 Weeks
- It can be scientifically demonstrated that the fetus hears and reacts
to sound. (1.)
- Fetuses display individual personality. When a needle for
amniocentesis (a method of prenatal testing for genetic anomalies) is
introduced into the uterus, the fetus will react. Different fetuses react
differently to this experience. Some kick or punch at the needle, some grab it,
some shy away. (1.)
- The fetus can experience pleasure and happiness or displeasure and
fear. Male fetuses of this age sometimes have erections
while sucking their thumbs; the baby boy's body reacts to his enjoyment of
sucking his thumb. Fetuses at this age are also startled, and their heart rates
increased, by loud unpleasant noises. (1.)
- The mother may first feel her baby kicking. He or she is finally
strong enough to stretch the uterus with his or her movements. (11.)
.
15 to 16 Weeks
- The fetus's entire torso is sensitive to touch. (1.)
- The fetus's nerves are being coated with a fatty substance called
myelin. Myelin makes faster nerve transmissions possible and insulates the
nerves so that impulses can be sent over longer distances. (14.)
Some pro-choice sources claim that myelinization does not occur for
another month to two months, and that no significant brain activity or
awareness is possible until that time. Put simply, they're wrong. There is
piles of evidence, scientific and anecdotal, to prove that the fetus is
sentient long before it has myelin.
- The fetus has fingerprints. (14.)
.
19 Weeks
- This is the youngest that any baby has been born and survived. Babies
born this young may have problems with infections, since their immune systems
are still immature, and may have trouble breathing. They may also suffer from
developmental problems later in life.
.
24 Weeks
- This is the age at which the law considers a baby "viable," or able
to survive outside the womb. This is a legal distinction, not a medical one.
Babies born younger than 24 weeks may live, though their chances of both
survival and long-term health improve dramatically after 24 weeks. After this
point in time, abortion is technically supposed to be severely
legally restricted. However, many states will allow elective abortion after
this point, due to fetal abnormalities, or if the pregnancy was the result of
rape or incest.
.
38 Weeks
- This is the age at which a baby should, ideally, be born. At 38 weeks
the baby's lungs are fully functional and his or her immune system is ready for
the outside world.
..
.
.
.
.
Works Cited: Text
1.) Chamberlain, David, ed.. "The fetal senses." Life before birth.
http://www.birthpsychology.com/lifebefore/fetalsense.html
2.) Evidence of Dr. Harley Smyth (Position), Borowski v. The Attorney
General of Canada 8C.C.C. (3d) 1983; See Trial for Life, Vol. 1, Alliance
Against Abortion, Winnipeg, 1984, Testimony of Dr. Harley Smyth, p. 492.
3.) Flanagan, Geraldine Lux. Beginning Life. New York: DK Publishing,
1996.
4.) Gray's Anatomy. Philadelphia: Running Press, 1974.
5.) Hill, Mark. "Development of the Placenta." UNSW Embryology HomePage:
Development Notes. (2000.)
http://anatomy.med.unsw.edu.au/cbl/embryo/Notes/placenta.htm
6.) Hill, Mark. "Week 4 Development - Introduction." UNSW Embryology
HomePage: Development Notes. (2000).
http://anatomy.med.unsw.edu.au/cbl/embryo/Notes/week4_5.htm
7.) Hill, Mark. "Week 4 Development - Early Nervous System." UNSW
Embryology HomePage: Development Notes. (2000).
http://anatomy.med.unsw.edu.au/cbl/embryo/Notes/week4.htm
8.) Houp, Katherine H. "Embryology." Piotrowski, Nancy A., ed. v. 4
Magill's medical guide: health and illness suppliment. Salem Press; 1996. pp.
1069-1073.
9.) "Milestones in fetal development." Ohio Right to Life: Human
Development. (24 Nov. 1995). http://www.ohiolife.org/develop/mileston.htm
10.) "Neurology." Piotrowski, Nancy A., ed. v. 4 Magill's medical guide:
health and illness suppliment. Salem Press, 1996. pp. 1397 - 1400
11.) Nilsson, Lennart. A Child is Born. New York: Dell Publishing, 1990.
12.) Purves, William K.; Gordon, H. Orians, H; Heller, Craig H.; Sadava,
David. Life: the science of biology. Salt Lake City, UT: Sinauer Associates,
1998.
13.) Ross, Anna E. "Summary of prenatal development." Dr. Ross'
Vertebrate Embryology Course (Bio 211): Contents of Unit 2 Embryology Lecture
Notes. (Fall 1996).
http://www.cbu.edu/~aross/emlec-u2.HTM#Summary_of_Prenatal_Development
14.) "Week 16." MouseWorks: The Visible Embryo. (2000.)
http://www.visembryo.com/baby/week16.html
.
Works Cited: Photographs
1.) Dr. R. Forman, London Gynaecology and Fertility Centre.
Published in:
Flanagan, Geraldine Lux. Beginning Life. New York: DK
Publishing, 1996. p. 22
2.) Carnegie Institute of Washington, Published in:
Flanagan, Geraldine Lux. Beginning Life. New York: DK
Publishing, 1996. p.39
3.) Carnegie Institute of Washington, Published in:
Flanagan, Geraldine Lux. Beginning Life. New York: DK
Publishing, 1996. p.39
4.) Nilsson, Lennart. A Child is Born. New York: Dell
Publishing, 1990. p.79
5.) Nilsson, Lennart. A Child is Born. New York: Dell
Publishing, 1990. p.81
6.) Flanagan, Geraldine Lux. Beginning Life. New York: DK
Publishing, 1996. p.44
7.) Nilsson, Lennart. A Child is Born. New York: Dell
Publishing, 1990. p.85
8.) Nilsson, Lennart. A Child is Born. New York: Dell
Publishing, 1990. p.90
9.) Nilsson, Lennart. A Child is Born. New York: Dell
Publishing, 1990. p.109
10.) Dr. J.D. Bromhall. Published in:
Flanagan, Geraldine Lux. Beginning Life. New York: DK
Publishing, 1996. p.66
11.) Anthea Seiveking. Published in:
Flanagan, Geraldine Lux. Beginning Life. New York: DK
Publishing, 1996. p.104