Bu çalışmada, Karayaka koyununda M.semitendinosus ve M.rhomboideus cervicis'in yapısal ve histokimyasal özellikleri incelendi. M.semitendinosus glikojenden zengin lipidden fakir, M.rhomboideus cervicis'in ise glikojenden fakir lipidden zengin kas fibrillerinden oluştuğu görüldü. Her iki kasta asit ve alkali preinkubasyon sonrası ATP-ase reaksiyonuyla 3 tip kas teli (tip I, tip IIA ve tip IIB) belirlendi. M.semitendinosus'da tip II kas fibrilleri, M.rhomboideus cervicis'de tip I kas telleri yüksek oranda bulundu. Bu bulgular; kas fibril tiplerinin, kasın fonksiyonel aktivitesiyle ilişkili olarak kaslarda değişen oranlarda bulunabileceğini göstermektedir.

In this study, the structural and the histochemical characteristics of M. Semitendinosus and M. rhomboideus cervicis were investigated in Karayaka sheeps. It was indicated that there were a lot of muscle fibres which had more glycogene and less lipid in M. Semitendinosus, whereas more lipid and less glycogen in M. rhomboideus cer-vicis. Three types of muscle fibers (type I, IIA and IIB) were identified by ATP-ase reactions after acid and alkaline preincubations in both muscles. M. Semitendinosus had the highest percentage of type II fibers but M. rhomboideus cervicis had the highest percentage of type 1. These results indicate that muscle fiber types could be found in varying proportions in relations to the functional activity of the muscle.