Data/hora: 16/06/2024 17:24:50

Biblioteca(s): | Embrapa Caprinos e Ovinos.
Data corrente: | 01/08/1992
Data da última atualização: | 16/01/2024
Autoria: | TODD, T. W.; WHARTON, R. E.; TODD, A. W.
Título: | The effect of thyroid deficiency upon bodily growth and skeletal maturation in the sheep.
Ano de publicação: | 1938
Fonte/Imprenta: | American Journal of Anatomy, v. 63, n. 1, p. 37-78, Jul. 1938.
DOI: | 10.1002/aja.1000630103
Idioma: | Inglês
Conteúdo: | Abstract: 1. This study is based upon the skulls and/or skeletons of five pairs of twin sheep, one of each pair being thyroidectomized in early life. To these pairs are added five other thyroidectomized animals of which we have not the normal twins, and also five normal skeletons from the Hamann Museum and the Museum of the Royal College of Surgeons, London, and fourteen skulls from the Hamann Museum. 2. The details of skull growth have already been presented in former articles (Todd and Wharton, '34 a, b). The segregation of dimensional growth from development or maturation progress is much more difficult in the skull than in the skeleton. Hence the earlier articles on skull avoided all reference to the purely maturation phenomenon of suture closure and touched but lightly on tooth eruption in order to avoid obscuring the features which are distinctly those of growth. 3. The general results but not necessarily the specific or direct effects of thyroidectomy are a) deficient growth and modelling of the epiphyses themselves, b) defective development of age characters on both epiphysis and adjacent shaft, c) diminished velocity of growth of shaft. There is no modification of bone texture, weight, thickness or modelling of shaft and no prolongation of the growth period to compensate for diminished velocity. 4. The locus of damage to both growth and maturation patterns is definitely and solely the diaphyso-epiphysial plane. Thus body framework is affected but viscera and brain largely escape mutilation both in size and in structure. 5. No immediate results are evident from thyroidectomy but, 2 months after operation usually, that is, when the animal is 3 months old, they become evident as a failure to gain adequately in weight. 6. The direct effect of hypothyroidism is probably restricted purely to the modification of growth velocity. The effect on maturation seems to be indirect, produced through disturbance of the bodily endocrine pattern. 7. The effect upon the growth pattern of the skeleton is to produce what seems to be a progressively more marked inhibition but is really an inhibition of velocity without prolongation of the growth period. The result is to reduce the proportions of the limbs to those of the unimproved wild sheep of little meat or wool value. 8. The effect on maturation, an effect which we believe to be indirect and produced through disturbance of the general endocrine pattern, is to reduce velocity approximately by onehalf. Probably, like the growth impulse, maturation progress in the skeleton ultimately fades out but our observations go no further than the sheep of 5 years. 9. Obvious pathological changes in the diaphyso-epiphysial plane are not evident until the animal is 2 years old or more. The pathological features are a) irregular exuberances on the shaft end resembling ossified ‘proud flesh’; b) inturned, clawed, trachoma-like epiphysial margins ; c) a small, poorly modelled, ill-fitting epiphysis scarcely covering the shaft end. 10. In the skull the disturbance of developmental growth is most marked in the premaxilla and maxilla but also affects other parts of the face.
Palavras-Chave: | Functional disorders; Tireoidectomia.
Thesagro: | Deficiência; Doença Metabólica; Ovino; Tireóide.
Thesaurus Nal: | Bone diseases; Growth disorders; Sheep diseases; Thyroid diseases.
Categoria do assunto: | H Saúde e Patologia
Registro original: | Embrapa Caprinos e Ovinos (CNPC)
Exemplares: | CNPC - (9085-1) - ADD - AP - DD -  -  -  - DIS