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(A) Dorsal view. (B) Lateral view. (C) Ventral view. (D) Mouth structure. [1] Gosner stage is a generalized system of describing stages of embryonal and larval development in anurans (frogs and toads). The Gosner system includes 46 numbered stages, from fertilized embryo (stage 1) to the completion of metamorphosis (stage 46).
A neurula is a vertebrate embryo at the early stage of development in which neurulation occurs. The neurula stage is preceded by the gastrula stage; consequentially, neurulation is preceded by gastrulation. [1] Neurulation marks the beginning of the process of organogenesis. [2] Mice, chicks, and frogs are common experimental models for ...
Noggin, also known as NOG, is a protein that is involved in the development of many body tissues, including nerve tissue, muscles, and bones. In humans, noggin is encoded by the NOG gene . [ 5 ] The amino acid sequence of human noggin is highly homologous to that of rat , mouse , and Xenopus (an aquatic frog genus).
The neural fold is a structure that arises during neurulation in the embryonic development of both birds and mammals among other organisms. [1] [2] This structure is associated with primary neurulation, meaning that it forms by the coming together of tissue layers, rather than a clustering, and subsequent hollowing out, of individual cells (known as secondary neurulation).
Development of the sagittal crest is thought to be connected to the development of this muscle. A sagittal crest usually develops during the juvenile stage of an animal in conjunction with the growth of the temporalis muscle, as a result of convergence and gradual heightening of the temporal lines. [citation needed]
This tissue derives from the unsegmented paraxial mesoderm and prechordal mesoderm. Tissues derived from the head mesoderm include connective tissues and the muscles of the face. The head mesoderm forms through a separate signaling circuit than the segmented paraxial mesoderm, though also involving BMP and fibroblast growth factor signaling.
Cranial kinesis is the term for significant movement of skull bones relative to each other in addition to movement at the joint between the upper and lower jaws. It is usually taken to mean relative movement between the upper jaw and the braincase. [1] Most vertebrates have some form of a kinetic skull. [1]
The development of the somites depends on a clock mechanism as described by the clock and wavefront model. In one description of the model, oscillating Notch and Wnt signals provide the clock. The wave is a gradient of the fibroblast growth factor protein that is rostral to caudal (nose to tail gradient). Somites form one after the other down ...