Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: Andrew K Fletcher on 02/09/2007 21:14:40
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What possible reason is there for a developing baby to spend most of it's time head up, could the development be benefiting from this posture?
Andrew
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Anyone thought they may be benefiting from being the right way up in relation to gravity yet?
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Do you mean before or after birth?
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before birth
After birth is where I am heading with this if I can get some replies
Thanks Stef
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Great question Andrew.
I think you know me well enough to be in a position to unfortunately not give you an academically informed opinion....but I wonder if it's important for the orientation of the baby to be the same as the parent..ie: the right way up !...which is is exactly what you refer to.
I wonder if there would be a developmental issue if it was the other way round for the majority of the pregnancy ?...
Not too sure how well balanced a baby's senses are but I would imagine spending most of the time upside down during pregnancy to be uncomfortable if not anything else.
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I would think too much blood flow in the brain area during early development could cause a problem and during the most critical development period what the first 3 trimesters, would enable good blood flow perhaps throughout the bodies lower extremities etc.
Perhaps the fetus needs the gravitational pull in upright position early on until close to the end to promote and underdeveloped circulatory system until things are in place. The lungs develop and become functioning towards the end correct, as some premature infant's lungs are not yet fully developed..Perhaps that holds true with the circulatory system or the heart and valves that will be pumping the blood. More energy spent on development while using gravity to increase circulation.. I don't know but that would be my uneducated motherly guess! LOL
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To begin to understand why being the right way up is important, it makes sense to start at the start of development.
This abstract shows what happens when an embryo is artificially horizontally managed, but shows also what happens when gravity is allowed to run in the correct direction through the developing foetus.
Effect of Gravity on the Interaction between the Avian Germ and Neighbouring Ooplasm in Inverted Egg Yolk Balls
Authors: M. Callebaut; F. Harrisson; H. Bortier
DOI: 10.1076/ejom.39.1.27.7986
Publication Frequency: 5 issues per year
Published in: European Journal of Morphology, Volume 39, Issue 1 February 2001 , pages 27 - 38
Subject: Physiology;
Date of change: 2007
Abstract
The developmental capacities of an avian germ (from before symmetrization to the moment of laying) are strongly diminished after inversion of its egg yolk ball followed by culture in egg white. Our present experiments show that even when the avian germ is completely horizontally inverted (without an upper or lower border) below its egg yolk ball before symmetrization, symmetrization and gastrulation phenomena take place. The germ grows slower and becomes smaller than after normal incubation. After culture of inverted unincubated germs, localized on freshly laid eggs, the closure of the neural tube is impaired and it remains open over a long distance. Although a primitive streak (PS) develops, mesoderm migration (mainly from the lateral part of the area pellucida) is also impaired. On sections through the germinal disc one can see the abnormal upward migration into the depth of the ooplasm and yolk of cells from the germ wall and the development of large cellular extensions encircling the yolk globules. Most prominent is the loss of contact between the superficial cell layers and the deep layer elements (junctional endoblast and yolk endoblast in the area opaca). Large areas without deep layer elements (even visible on surface micrographs) develop in the area vasculosa and area vitellina interna. The margin of overgrowth grows and extends normally over the egg yolk ball. An autoradiographic study after labelling of the yolk layers in inverted egg yolks reveals that mainly compression of the peripheral subgerminal and perigerminal ooplasm takes place. This suggests that the compression by the neighbouring yolk and upwards growth of cells are at the origin of the impaired development. After return to the normal upward orientation of the germ on the topmost part of the egg yolk ball, a more or less pronounced restoration to normal development takes place (depending on the duration of the inversion period and the age of the germ).
The developing foetus obviously benefits from the effects of gravity, yet physiology today fails miserably to recognise why this is so.
Andrew
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What possible reason is there for a developing baby to spend most of it's time head up, could the development be benefiting from this posture?
Andrew
The devloping baby will certainly need to stand up in the future with the Head held high. The heart has evloved to support this kind physiology .... Maximum purified blood is pumped against the gravity... The Gravity gives a sense of direction for proper functioning of the brain.
Thats why Baby's Head is up most of the time.
Moreover it is a more stable position in which the chances of head injury is minimum.
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DKV
The point is that when an embryo develops, there is no heart pumping against gravity as you put it. Also on taking the first breath, a new born baby's blood flow changes direction. Which also suggests that the heart in the developing baby is not running in accordance with the gravity resistance flow you mentioned.
I think you are correct with gravity giving a sense of direction and indeed you are correct with gravity facilitating proper function of the brain and neural network.
I would go further and suggest that gravity provides the stimulus that initiates circulation prior to and during fertilization right through to our eventual deaths and that the first breath stimulates a density flow to occur in the artery that provides the tension to close the previous route of bloodflow from then on.