Organogenesis of Frog
The primary organ rudiments from ectoderm, mesoderm and endo-derm get well established during the processes of gastrulation and neurula-tion. In the next stage the primary organ rudiments subdivide into secondary organ rudiments. These rudiments get differentiated into various organs and organ systems.
The neurula of frog has three kinds of ectodermal tissues namely, epi-dermal ectoderm, neural ectoderm and neural crest cells.
The epidermal derivatives are the skin, olfactory sense organs, ear, lateral line sense organs, median fins, external gills and lining of mouth and anus.
This layer of cells form the central nervous system and peripheral nervous systems.
The mesodermal derivatives are the limbs, endoskeleton, heart, blood vessels, kidney, coelom and reproductive organs.
The predominant endodermal organs are the organs of the alimentary canal, lungs, pancreas and urinary bladder.
The heart is a mesodermal derivative. It develops on the ventral side of pharynx. It is formed from the lateral plate mesoderm. Initially the heart is formed as a straight tube. Later it gets folded to form the chambered heart.
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