Histological studies on the vestibular organ of frog embryos and larvae after simulated weightlessness.
The ontology of gravity receptors is discussed. As well as phylogenetic aspects of the question, we may ask whether the different gravity receptors in plants and animals derive from the same source; did they evolve from a general sensitivity of the living cell or do they represent parallel inventions. One may also ask whether during ontogeny of the receptor it receives information from gravity or whether the development of function of the organ is an autonomous process. In many cases ontogeny shows traces of phylogeny. Statoliths, e.g. the differentiating statolith membranes of the frog embryo, look somewhat like sedimentational structures. Furthermore the amphibian embryo in its relatively early stages takes up a special position in relation to the direction of gravity. Which mechanism is involved here? The materials studied were frog embryos and larvae which developed within a fast rotating clinostat. The results may help to answer the question as to whether the differentiation of the frog statolith membrane is an autonomous process.
Briegleb
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DFVLR, Institut fur Flugmedizin, Bonn, Bad Godesberg, FRG.
D000818:Animals; D004625:Embryo, Nonmammalian / Q000033:anatomy & histology; D047108:Embryonic Development; D006112:Gravitation; D018466:Gravity Sensing / Q000502:physiology*; D007814:Larva / Q000033:anatomy & histology / Q000254:growth & development; D010802:Phylogeny; D011896:Rana temporaria; D012399:Rotation; D014722:Vestibule, Labyrinth / Q000033:anatomy & histology* / Q000196:embryology* / Q000254:growth & development*; D018474:Weightlessness Simulation