Take a small unstretched and not too dense rubber ball having approximately a diameter of about inch, with a small hole, through which when pressed can leave the air. Suppose instead of rubber, the wall consists of small cells, connected to each other and became, owing to mutual pressure, in the form of a multifaceted. It will be to represent the blastoderm. Now press your finger to one side of the ball until long as it does not touch the other hand in such a way that will calyx. This action will replace the process of intussusception. Imagine that by continuing this process, the hemispherical Cup becomes very deep and her hole is narrowed as long as the Cup is not will take the form of a bag, whose inner wall is everywhere in contact with the outer. This pouch will be a consisting of two layers, the simplest ancestral form of the Metazoa - the "gastrula": the form that you permanently retain some of the lower types; all it needs is tentacles surrounding the opening of the pouch, in order to obtain an ordinary Hydra. Here we especially note the fact that of these two layers, outer called, according to embryological terminology èpiblastom, continues to communicate with the external forces and substances between the as internal called gipoblastom, comes in contact only with such substances that are made to surround them with a food cavity. We should in addition, notice that in embryos with a more advanced Metazoa the organization appears between these two layers is a third, called mesoblast. It is noticeable those types of who have a process development is not dimmed by the presence of a large number of nutrients yolk. While the above impression and before the internal the surface of epiblast and gipoblasta will come in contact between them, from one or both of these inner surfaces, or from any plot one or the other of them separated cells or their equivalent amoeboid individuals, which form everywhere between the other two layer, never having, as is clear from the way it is education, communication with the external environment and its contents, as well as with get from her nutrients.
Take a small unstretched and not too dense rubber ball
ReplyDeletehaving approximately a diameter of about inch, with a small hole,
through which when pressed can leave the air. Suppose
instead of rubber, the wall consists of small cells, connected to each other
and became, owing to mutual pressure, in the form of a multifaceted. It will be
to represent the blastoderm. Now press your finger to one side of the ball until
long as it does not touch the other hand in such a way that will
calyx. This action will replace the process of intussusception. Imagine
that by continuing this process, the hemispherical Cup becomes
very deep and her hole is narrowed as long as the Cup is not
will take the form of a bag, whose inner wall is everywhere in contact with the
outer. This pouch will be a consisting of two layers,
the simplest ancestral form of the Metazoa - the "gastrula": the form that you
permanently retain some of the lower types; all it needs is tentacles
surrounding the opening of the pouch, in order to obtain an ordinary Hydra.
Here we especially note the fact that of these two layers,
outer called, according to embryological terminology èpiblastom,
continues to communicate with the external forces and substances between the
as internal called gipoblastom, comes in contact only with
such substances that are made to surround them with a food cavity. We
should in addition, notice that in embryos with a more advanced Metazoa
the organization appears between these two layers is a third, called
mesoblast. It is noticeable those types of who have a process
development is not dimmed by the presence of a large number of nutrients
yolk. While the above impression and before the internal
the surface of epiblast and gipoblasta will come in contact between them, from
one or both of these inner surfaces, or from any
plot one or the other of them separated cells or their equivalent
amoeboid individuals, which form everywhere between the other two
layer, never having, as is clear from the way it is
education, communication with the external environment and its contents, as well as with get
from her nutrients.