Enterocoely
Encyclopedia
Enterocoely is a process by which some animal embryos develop. In enterocoely, a mesoderm
is formed in a developing embryo
, in which the coelom forms from pouches "pinched" off of the digestive tract (also known as the embryonic gut, or archenteron
). This type of coelom formation occurs in deuterostome
animals, which for this reason are also known as enterocoelomates.
Enterocoelous development begins once the embryo
reaches the gastrula phase of development. At this point, there are two layers of cells - the ectoderm
(outermost) and the endoderm
(innermost) layers. The mesoderm
(middle layer) begins to form as two "pockets" of tissue (one above the endoderm, and one below) are formed via folding of the endoderm. These "pockets" begin to grow larger, and as they do so, they extend towards each other. When the two "pockets" of cells meet, the mesoderm is formed - a complete layer of tissue right in between the endoderm and ectoderm layers. This then leads to the formation of a coelom
.
Enterocoelous development is the stage of embryological development of deuterostomes in which the coelom
forms. The stage starts with the gastrula; as the archenteron
forms, pockets of migrating cells also form, creating another layer between the endoderm
and ectoderm
, the mesoderm
. These pockets gradually expand to form the coelom. An exception to this form of coelom development is the subphylum vertebrata which are definitely deuterostomes but exhibit schizocoelous
coelom formation.
In protostomes, the body cavity is formed by schizocoely.
Mesoderm
In all bilaterian animals, the mesoderm is one of the three primary germ cell layers in the very early embryo. The other two layers are the ectoderm and endoderm , with the mesoderm as the middle layer between them.The mesoderm forms mesenchyme , mesothelium, non-epithelial blood corpuscles and...
is formed in a developing embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
, in which the coelom forms from pouches "pinched" off of the digestive tract (also known as the embryonic gut, or archenteron
Archenteron
The primitive gut that forms during gastrulation in the developing blastula is known as the archenteron. It develops into the digestive tract of an animal....
). This type of coelom formation occurs in deuterostome
Deuterostome
Deuterostomes are a superphylum of animals. They are a subtaxon of the Bilateria branch of the subregnum Eumetazoa, and are opposed to the protostomes...
animals, which for this reason are also known as enterocoelomates.
Enterocoelous development begins once the embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
reaches the gastrula phase of development. At this point, there are two layers of cells - the ectoderm
Ectoderm
The "ectoderm" is one of the three primary germ cell layers in the very early embryo. The other two layers are the mesoderm and endoderm , with the ectoderm as the most exterior layer...
(outermost) and the endoderm
Endoderm
Endoderm is one of the three primary germ cell layers in the very early embryo. The other two layers are the ectoderm and mesoderm , with the endoderm as the intermost layer...
(innermost) layers. The mesoderm
Mesoderm
In all bilaterian animals, the mesoderm is one of the three primary germ cell layers in the very early embryo. The other two layers are the ectoderm and endoderm , with the mesoderm as the middle layer between them.The mesoderm forms mesenchyme , mesothelium, non-epithelial blood corpuscles and...
(middle layer) begins to form as two "pockets" of tissue (one above the endoderm, and one below) are formed via folding of the endoderm. These "pockets" begin to grow larger, and as they do so, they extend towards each other. When the two "pockets" of cells meet, the mesoderm is formed - a complete layer of tissue right in between the endoderm and ectoderm layers. This then leads to the formation of a coelom
Coelom
The coelom is a fluid-filled cavity formed within the mesoderm. Coeloms developed in triploblasts but were subsequently lost in several lineages. Loss of coelom is correlated with reduction in body size...
.
Enterocoelous development is the stage of embryological development of deuterostomes in which the coelom
Coelom
The coelom is a fluid-filled cavity formed within the mesoderm. Coeloms developed in triploblasts but were subsequently lost in several lineages. Loss of coelom is correlated with reduction in body size...
forms. The stage starts with the gastrula; as the archenteron
Archenteron
The primitive gut that forms during gastrulation in the developing blastula is known as the archenteron. It develops into the digestive tract of an animal....
forms, pockets of migrating cells also form, creating another layer between the endoderm
Endoderm
Endoderm is one of the three primary germ cell layers in the very early embryo. The other two layers are the ectoderm and mesoderm , with the endoderm as the intermost layer...
and ectoderm
Ectoderm
The "ectoderm" is one of the three primary germ cell layers in the very early embryo. The other two layers are the mesoderm and endoderm , with the ectoderm as the most exterior layer...
, the mesoderm
Mesoderm
In all bilaterian animals, the mesoderm is one of the three primary germ cell layers in the very early embryo. The other two layers are the ectoderm and endoderm , with the mesoderm as the middle layer between them.The mesoderm forms mesenchyme , mesothelium, non-epithelial blood corpuscles and...
. These pockets gradually expand to form the coelom. An exception to this form of coelom development is the subphylum vertebrata which are definitely deuterostomes but exhibit schizocoelous
Schizocoelous
Schizocoely is a process by which some animal embryos develop. Animals which develop through schizocoely are known as schizocoelomates...
coelom formation.
In protostomes, the body cavity is formed by schizocoely.