The Micro-structure And Ultrastructure Of Pineal Gland In Yak

Histological structure of pineal gland of 12 Yaks (male and female in half) were observed through light and electron microscopes. It was indicated that the pineal gland of yak is capsuled, and full of capillary vessel under capsule and in the parenchyma. No lobules were found in the parenchyma, which is consisted of pinealocyte and glial cells. The pinealocyte is divided into light and dark cells. Under the light microscope, there is one to several processes in the pinealocyte of yak. And the nucleus is clear, big, round and dense stained. The nucleolus is also clear and obvious, and the cytoplasm is weak basophilic. Under the electron microscope, the pinealocyte nucleus is regular, and chromatin is even in the nucleus, only very little heterozygous chromatin locating peri-nucleus. There are abundant of mitochondria, endoplasmic reticulum, ribosome, hepatin, microfilament and microtubule. But there is very fewer golgi complex in the yak pinealocyte. The typical organelle synaptic ribbons in pinealocyte were observed. The organelle is the â…¡ type of the synaptic ribbon, spherical, and mainly located peri-membrane of the pinealocyte. Comparing to pinealocyte, the glial cell is small, and the nucleus is abnormity, strong basophilic and dense stained. The cytoplasm is weak stained. There are also several processes in the glial cell. The glial cell is flat and polygonal, and its nucleus is small and oval, but only a few are irregular. There are always lacked of notable nucleolus. The double membranes of the nucleus are prominent. Chromatin is always equally distributed in the nucleus, only a few are dense in the peri-nucleus. There are also abundant of mitochondria. But there are fewer of golgi apparatus, granular endoplasmic reticulum and ribosome, etc. Some lipomealopin deposition was found in the glial cell. The deposition granular is packaged by membrane. And its morphology and size are various. The conjunctions between the pinealocytes are synapses, and among the parenchyma cells there are also desmosomes and gap junction. Some pigment cells are around the blood vessel. There are also some encephalolith in the pineal gland of yak, and it becomes more and more obvious with the aging.