Prenatal thyroid gland in sheep with regard to the presence of isthmus.
We studied the embryonal thyroid gland in 18 foetuses of sheep of Slovac merino breed by light microscopy in the period from 32nd to 36th day of evolution. We found that in the majority of sheep foetuses, the thyroid gland consists of two separate lobes and their structure was the same during the afore-mentioned period. Parenchyma, composed of solid cell networks or cell groups in the form of nests, was irregularly divided by septa, containing embryonal blood vessels. Almost all cases of this experiment showed slight asymmetry of lobes. In one case the asymmetry reached a considerable proportion - nearly the length of one lobe. Glandular isthmus was presented in only eight cases from 18 foetuses. We did not find fibrous isthmus in any case.
Hájovská
K
K
Univerzita Veterinárnej Medicíny, Kosice, Slovensko. katarina@impala.uem.mz
D000818:Animals; D012756:Sheep / Q000196:embryology*; D013961:Thyroid Gland / Q000196:embryology*