Axial Rudiment Complex

The axial complex of origins in chordates is initially located on the lateral side of the body (lateral mesoderm), then moves into the body (ventral plate) and finally ends up on the dorsal (dorsal) part of it. The following synonymous names for the term “axial skeleton” are allowed: axial skeletal system, rudimentary axial skeleton and musculoskeletal axial rod. In what follows we will use the latter term.

At the same time, a vascular network appears: the first blood tube, then larger vessels, most of which go to the trunk, or, more precisely, to the proboscis - the head kidneys. The first brain (brain vesicle, brain sac) is formed lateral to the axial complex, medially of which the rudimentary sensory organs (such as the eye, lens, ear, olfactory vesicles, etc.) are located. The primitive mouth, unpaired at first, is formed in the place of the first brain, in the same plane with it and under the proboscis, i.e. behind the center of the axial rod skeleton. He soon acquires a pair. The dimensions of all three eyes are half the width of the head; only the upper eye is larger

The axial complex of the rudiment (axial skeleton, or axial sac) is a set of rudiments of the peripheral nervous system and skeletal rudiments, which are located on the dorsal (dorsal) side of the body in embryos of chordate animals. The structure of the axial complex can be used to study the evolution of animals and the development of major body systems.

The axial complex provides mobility and stability to the body, and is also involved in the formation of important organs and systems of the body, such as nerves, muscles, tendons, bones and joints