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splenic development

Saturday 18 May 2013

spleen development

The spleen develops from progenitor cells within the
dorsal mesogastrium adjacent to stomach and
pancreas.

The process is controlled by a number of
transcription factors expressed by early spleen
mesenchymal cells. These include Nkx2.3, Nkx3.3,
Pbx1, Sox11, Tcf21, Tlx1 and WT1.

Mouse studies
have shown that absence of any of these factors lead
to either complete splenic agenesis or marked
hypolasia indicating a very complex regulation of
splenic development. In humans spleen is detectable
by 5th week of gestation and blood vessel appear
around the 9th week.

Function of the spleen in the fetus
varies from the postnatal spleen.

The spleen is the
main source of hematopoiesis in the fetus where is this
function reduces dramatically after birth.

In the postnatal period, the spleen plays a major role in
the production of antibodies against blood borne
antigens and polysaccharide antigens.

Next to this
immunological function the spleen is also involved in
removal of effete cells from the bloodstream.

This dual
role is reflected in the complex architecture of the
spleen.

The immunological section is formed by the
white pulp that follows the branching central artery
while the red pulp takes part in removal of defective
erythrocytes and foreign elements from the
bloodstream.