Observation On The Histological Structure Of The Yak (Bos Grunniens) Oviduct During Reproductive Cycle

Fifteen female yaks (Bos grunniens) at reproductive cycle were used to study the histologicalstructure of oviduct by anatomical and histological methods. The results were as follows:1. The histological structure of yak's oviduct was similar to the other domestic animals.The mucous epithelium of yak's oviduct was consisted of ciliated cells, secretory cells, a few ofbasal cells and peg cells. The apices of secretory cells displayed two types of cytoplasmicprotrusions. A kind of protrusions was low, blunt and without nuclei, had many positive granulesin PAS reaction in the supranuclear cytoplasm. The other was high and contained nuclei, butwithout positive granules in PAS reaction.2. It was firstly observed that the characteristics of yak's oviduct during estrus cycle wasthe change of secretory cells. During the follicular phase, the apexes of secretory cells displayedcytoplasmic protrusion with nuclei and had many positive granules in PAS reaction in thesupranuclear cytoplasm. The granules in PAS were the most in the ampulla, the least in theisthmus. At luteal phase, the secretory granules of secretory cells in the infudibulum and ampulladisappeared and cytoplasmic protrusions, extending beyond the luminal border the ciliated cellsand often containing the nucleus, were predominant. But the secretory granules in the isthmusdecreased indistinctively and the protrusions were unconspicuous.3. At early pregnancy there were two types of protrusions in the infundibulum. One typecontained nuclei and the other without. The degree of protrusions was low and had a fewsecretory granules. In the ampulla, the protrusions of secretory cells were all without nuclei andhad many secretory granules. In the isthmus the secretory cells had no protrusions and secretorygranules. The nuclei of ciliated cells were vacuolar at yak's oviduct.