Ontogenetické změny štítné žlázy králíka

The literature review of this thesis describes the thyroid gland in terms of morphology, physiology, microscopic structure, and its prenatal and postnatal development. The practical part focused on the monitoring of morphometric changes of the thyroid gland during the first 39 days of postnatal development at 24 New Zealand white rabbits. Morphometric measurements carried out were: the circumference, length and width of follicles and the height of thyrocytes. At birth, the average circumference of follicles was 134.54 ? 7,81m, with length of 41.85 ? 0.93 ?m, width of 39.45 ? 4.05 ?m, and the average height of thyrocytes was 5.12 ? 0.06 ?m. The measurements were repeated in 39 days of age (at the end of the experiment) with the average circumference of follicles being 231.53 ? 37.95 ?m, length of 71.09 ? 12.19 ?m, width of 68.97 ? 10.02 ?m and the height of thyrocytes 5.69 ? 0.42 ?m. All parameters with the exception of thyrocytes showed increased values. On average the circumference of follicles from birth to 39 days of age changed by 72.1%, the height of follicles by 69.9%, with the highest difference in width by 77.4%. At the age of 5 days the reduction in follicle size was observed, possibly due to the adaptation of thyroid gland to the postnatal period