Development of Trunk and Body wall in Animals

Development of Trunk and Body wall in Animals

The lateral folding and ventral fusion described in the formation of the sides of the head continues caudally. As the lateral folding behind the head form the cylindrical shaped embryo, it partitions a part of the coelom and part of the yolksac. These are incorporated into the body of the embryo forming the intra-embryonic coelom and the future gut of the embryo.

When the folds are fused ventrally and the basic body plan of the embryo is established, the somatopleurae of the folds form the body wall of the embryo. The splanchnopleurae of the folds form the gut and supporting mesentries.

A tail fold is formed in a manner similar to that of head. The resulting endoderm lined cavity in the tail area is the hindgut. The gut between the hindgut and the foregut is referred as midgut. With the completion of the body wall along the entire length of the embryo, the basic hollow cylindrical tube within a tube, the body pattern is complete.