ı could not write recently.two days ago ı gave a presentation about bone tissue in my school.the important point which stuck in my mind are; 1)the difference of primary and secondary bone(primary bone is irregular and secondary bone is regular. the distinctive factor is the structure. we see the second bone(compact bone and spongious bone) have a lamellar structure), 2)and it is said that osteoblasts have euchromatin nucleus ocyteocits have heterochromatine nucleus but we see in some electromicroscophic photos some ocyteocytes' have euchromatin nucleus. ı think they are the cells near the vessels carrying and getting back nutrients to and from the other ocyteocits away from the vessels.because of their much more activates they have euchromatin nucleus....tomorrow ı will go on...