Wednesday, September 19, 2007

Room 71

F O R M




The Beginning of Form.

Floating in a fluid filed sac called the amnion, the 10-week old foetus is a recognisable, if rudimentary, human being. It is about 2 inches long (~ 50 mm ). The fringed tissue seen at the right is the placenta, through which, via the arteries and vein of the umbilical cord, the foetus receives oxygen and food products it requires from its mother and discards its wastes.

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WITHIN SIX WEEKS - FEATURES EMERGE






Left Hand Photograph (above) - Four weeks old (~28 days) , the embryo nestles inside a mass of feathery tissue called the chorion, which in turn is implanted in the uterus, cockle-bur fashion. The embryo draws nutrients from its mother through outgrowths, called villi, which help form the placenta.

The Centre Photograph (above) - shows a series of bulges (in the foetus inside the chorion) at ~26 days marks the areas of head and heart [the heart is the first organ to differentiate, develop and begin pumping - which it does as other cells form the nervous system etc] . Here - the swelling at the top will become the forebrain; the smaller ones beneath them that look like cheeks are actually the lower jaw. The depression between these two sets of bulges will become the mouth. At the very top, a tiny hole is the end of a tube that forms the brain and spinal cord. Below the head, on the right, is another bulge containing the heart, where the first heart beats have begun.

Photograph on Right (above) - Eyes, ears and limbs have appeared by the sixth week (~42 days) , the latter as arm and leg "buds". The EYE looks like a dark-rimmed circle; justinfrontof it is a bulge, part of which will form the nose. The series of little folds that look like a mouth are actually the beginnings of the outer ear. These features, which now seem out of place, will take their correct position when the the embryo acquires a neck and begins to uncurl. The embryo is about an inch (25 mm) from crown to rump.


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AT NINE WEEKS (~63 days) HANDS AND FINGERS EMERGE


SIXTH WEEKS OLD (ABOVE LEFT)

The yolk sac, prominent in this picture (above left) of an embryo at six weeks, produces red blood cells in the first two months of growth [these and the disease fighting leucocytes - or white blood cells and other blood material will eventually be produced (and indeed will re supply "normal" blood loss throughout life) in a developed being in the bone marrow - bone marrow cancer is what Leicester Kyle died of] - the yolk sac soon loses this function. It is rarely present at birth. Beneath the head, the arm can be seen with its developing hand.


NINE WEEKS OLD (ABOVE RIGHT) The embryo has developed well-formed fingers: its eye is assuming an oval shape. The embryo mow measures about 1 and 1/4 inches (~31 mm)
from crown to rump. The kidneys have become functioning at this time, adding foetal urine to amniotic fluid.

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NO PICTURE - ERROR

BY THE THIRD MONTH (~84 days) the developing form of life is not just a human but an individual
[ What is a human? What is an individual?] It has begun to show signs of distinctive physical characteristics. No longer called an embryo, it is now a foetus. During this month it may double in length. Growth proceeds from the head down, which lagged behind the hands in development, have acquired fanned-out toes.

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A SKELETON TAKES FORM AND MOTION BEGINS



The rib cage of an 11 week (~77 days) foetus can be seen in the chest region just below the elbows. The ribs and spinal column develop from cartilage cells, which begin to be replaced by bone cells at about the ninth week. Each rib grows out of a vertebra, but eventually a flexible joint will develop between the two.

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TWELVE WEEKS OLD - THE FIRST MOVEMENTS



The first movements are reflex gestures shown above in two pictures taken only seconds apart. Here, 12 weeks (~ 84 days / ~3 months old) the foetus raises its hand to its mouth and makes mouth movements suggestive of sucking. It also contracts the other hand. The substitution of bone for cartilage in the long bones of the arms and legs is now well under way.

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FIFTH TO SIXTH MONTH: ACTIVITIES MULTIPLY




Sucking its thumb at 4 and 1/2 months (~ 210 days/ ~ 30 weeks) the foetus foreshadows the
motions of nursing. The foetus's movements intensify and are felt by the mother as "quickenings"; a series of rhythmic jolts means [THAT] [THE] baby is hiccuping. Nearly six inches (~150 mm) from crown to rump, it has almost fully developed ears and eyes. The blood vessels show through its translucent skin.




Photograph left above. Floating in its sac the five-month foetus has settled into a favourite "lie" or resting position (each foetus picks its own). The umbilical cord is kept from getting kinked by the pressure of blood flowing through it.


Photograph of hand (right above). A six-month-old foetus reveals emerging fingernails; by birth they will have grown long enough to need trimming. The finger prints, which will forever mark it as unique, also begin to appear. The skin on its hands and feet have begun to thicken, in preparation for the wear and tear of postnatal life. At this stage the baby's grip is strong enough to hang on to anything within its reach. In fact, for reasons embryologists do not fully understand [is this still the case?], a foetus' grip is stronger than it is after birth. The waxy appearance comes from a protective film secreted by the skin.




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IN THE LAST TWO MONTHS


Seven months old.

The foetus has acquired certain immunities and accumulated fat for warmth in preparation for the outer world. By now its digestive and respiratory systems have become remarkably
efficient.

















FULL BORN AT NINE MONTHS



Nine months.

A baby emits a cry of life on being thrust into a cold, bright world.
Gone is the dark warmth of the mother's womb.
The umbilical cord is severed and closed off.
Surgical clamp.
Oxygen, which only moments before came from the placenta,
Is now supplied by the baby's own lungs.
No one quite knows what makes breathing start.
[Is this still the case?]
One theory is that when the fluid in the foetal lungs
Is forced out in the process of birth,
A vacuum is created which causes the baby
To inhale its first breath.

From then on, the baby is on its own.

1 comment:

Richard said...

very very good!