Septum Transversum

2020 ◽  
Author(s):  
Keyword(s):  
Development ◽  
1971 ◽  
Vol 26 (3) ◽  
pp. 481-495
Author(s):  
Par Elisabeth Houssaint ◽  
Nicole Le Douarin

Cholinesterases in the chick liver. The role of the endoderm in the appearance of the activity of cholinesterases in the hepatic mesenchyme The histochemical method of Koelle & Friedenwald (1949), as modified by Gerebtzoff (1953), has been used to investigate the distribution of cholinesterases in the chick embryonic and adult liver. Non-specific cholinesterases and, in a lower proportion acetylcholinesterase, have been detected in the endothelial cells of blood sinusoids of both adult and embryonic hepatic tissue. The hepatocytes do not show any cholinesterase activity. Cholinesterases appear precociously in the liver mesenchyme, since they already occur in the septum transversum of the 3-day-old chick embryo. An experimental procedure preventing the invasion of the hepatic mesenchymal Anlage by the endodermic cords has been used. The experimentally isolated hepatic mesenchyme shows an important cholinesterase activity; therefore this activity does not depend on the presence of the hepatocytes. The grafting of the determined hepatic endodern in the somatopleura of the 3-day-old chick embryo results in the development of hepatic tissue in the body wall. In this experimentally produced liver, cholinesterase activities are present in the endothelial cells which have arisen from somatopleura mesenchymal cells, though normally somatopleural mesenchyme does not possess these enzymes. The role of the endoderm in the appearance of this enzymic activity in the somatopleural mesenchyme is discussed.


Development ◽  
2000 ◽  
Vol 127 (2) ◽  
pp. 437-445 ◽  
Author(s):  
H. Brohmann ◽  
K. Jagla ◽  
C. Birchmeier

The homeobox gene Lbx1 is expressed in migrating hypaxial muscle precursor cells during development. These precursors delaminate from the lateral edge of the dermomyotome and form distinct streams that migrate over large distances, using characteristic paths. The targets of migration are limbs, septum transversum and the floor of the first branchial arch where the cells form skeletal muscle of limbs and shoulders, diaphragm and hypoglossal cord, respectively. We used gene targeting to analyse the function of Lbx1 in the mouse. Myogenic precursor cells delaminate from the dermomyotome in Lbx1 mutants, but migrate in an aberrant manner. Most critically affected are migrating cells that move to the limbs. Precursor cells that reach the dorsal limb field are absent. In the ventral limb, precursors are present but distributed in an abnormal manner. As a consequence, at birth some muscles in the forelimbs are completely lacking (extensor muscles) or reduced in size (flexor muscles). Hindlimb muscles are affected strongly, and distal limb muscles are more affected than proximal ones. Other migrating precursor cells heading towards the floor of the first branchial arch move along the appropriate path in Lbx1 mutants. However, these cells migrate less efficiently and reduced numbers of precursors reach their distal target. At birth, the internal lingual muscle is therefore reduced in size. We suggest that Lbx1 controls the expression of genes that are essential for the recognition or interpretation of cues that guide migrating muscle precursors and maintain their migratory potential.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Angel Dueñas ◽  
Almudena Expósito ◽  
María del Mar Muñoz ◽  
María José de Manuel ◽  
Andrea Cámara-Morales ◽  
...  

2005 ◽  
Vol 25 (7) ◽  
pp. 2622-2631 ◽  
Author(s):  
Roong Zhao ◽  
Alistair J. Watt ◽  
Jixuan Li ◽  
Jennifer Luebke-Wheeler ◽  
Edward E. Morrisey ◽  
...  

ABSTRACT Several lines of evidence suggest that GATA6 has an integral role in controlling development of the mammalian liver. Unfortunately, this proposal has been impossible to address directly because mouse embryos lacking GATA6 die during gastrulation. Here we show that the early embryonic deficiency associated with GATA6-knockout mice can be overcome by providing GATA6-null embryos with a wild-type extraembryonic endoderm with the use of tetraploid embryo complementation. Analysis of rescued Gata6 − / − embryos revealed that, although hepatic specification occurs normally, the specified cells fail to differentiate and the liver bud does not expand. Although GATA6 is expressed in multiple tissues that impact development of the liver, including the heart, septum transversum mesenchyme, and vasculature, all are relatively unaffected by loss of GATA6, which is consistent with a cell-autonomous requirement for GATA6 during hepatogenesis. We also demonstrate that a closely related GATA factor, GATA4, is expressed transiently in the prehepatic endoderm during hepatic specification and then lost during expansion of the hepatic primordium. Our data support the proposal that GATA4 and GATA6 are functionally redundant during hepatic specification but that GATA6 alone is available for liver bud growth and commitment of the endoderm to a hepatic cell fate.


2014 ◽  
Vol 111 (1) ◽  
pp. 87-92 ◽  
Author(s):  
TWK Fraser ◽  
PG Fjelldal ◽  
TJ Hansen ◽  
F Oppedal ◽  
RE Olsen ◽  
...  

2006 ◽  
Vol 12 (5) ◽  
pp. 390-398 ◽  
Author(s):  
Tresa Nesbitt ◽  
Aubrey Lemley ◽  
Jeff Davis ◽  
Michael J. Yost ◽  
Richard L. Goodwin ◽  
...  

Development of the epicardium is critical to proper heart formation. It provides all of the precursor cells that form the coronary system and supplies signals that stimulate cardiac myocyte proliferation. The epicardium forms from mesothelial cells associated with the septum transversum and is referred to as the proepicardium (PE). Two different methods by which these PE cells colonize the developing heart have been described. In avians, PE cells form a bridge to the heart over which PE cells migrate onto the heart. In fish and mammals, PE cells form vesicles of cells that detach from the mesothelium, float through the pericardial cavity, and attach to the heart. A previous study of rat PE development investigated this process at the histological level. Protein markers have been developed since this study. Thus, we investigated this important developmental process coupled with these new markers using other visualization techniques such as scanning electron microscopy (SEM) and confocal microscopy. Finally, a novel, three-dimensional (3-D) culture system was used to confirm the identity of the PE cells. In this study, we found convincing evidence that the rat PE cells directly attach to the heart in a manner similar to that observed in avians.


2021 ◽  
Author(s):  
Abdulaziz Shaher

As we advance our knowledge in understanding abdominal compartment syndrome, it is worth going back to revisit our basic embryologic development of the main determinant of the abdominal and thoracic cavities, i.e., the diaphragm. The abdominal and thoracic cavities used to be one cavity at some stage of the embryonic life — “intraembryonic coelom” — before the “septum transversum” — diaphragmatic origin — divided it into two cavities. Therefore, if a condition develops that will impair the diaphragm from separating the cavities, leading to the possibility of pressures to transmit from one cavity to another, this becomes relevant as abdominal compartment syndrome. Diaphragmatic eventration is a congenital developmental defect in the muscular portion of the diaphragm with preserved attachments to the sternum, ribs, and dorsolumbar spine, leading to a semi-membranous diaphragm that anatomically separates the two cavities, but not physiologically. In the case of high abdominal pressure, the pressure will transmit to the thoracic cavity, causing derangement in both the anatomy and physiology. This was reported and named “Thoracoabdominal Compartment Syndrome”.


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