what are the the caharacteristic figures of neuron? answer:the eurochromatine,spherical nucleus and the distinctive nucleolus.some times there are two nucleolus.the barr apparatus can be seen.we can't see centriole near the nucleus because the neurons do not divide. we see the centrioles at the periphere of perikaryon near the cilia.the function of cilia is not known excatly. it is known that it gets lost by the time except the neurons' have modified ciliaes rod and coni cells in the retina.the neurons have numerous mitochondrias which have spherical or flat shapes and their cristas are vertical or longitudinal.the nissl apparatus are characteristic figure of these cells and ıt is supposed that they protect neurones after travma or damaging events.ıt was seen when neurons were damaged the nissl aparatus dissolved and scattered everywhere of the some.the dendrites have the nissl apparatus,too but axons do not have for this reason it is an advantage for histologists to distinct axons from dentrites.all the neurons have only one axon but the number of dendrites can be changed.the microtubules and microfilamentes are very important for conducting organals,vesicles and metabolites.the protoplasma is syntesized in the soma and conducts to dentrites and axon.it is seen in the soma there are developet granular endoplasmic reticulum and golgi apparatus.the nissl apparatus are thought that they are consist of some granular endoplazmic retuculm cisternaes,free ribosomes and poliribosomes.these all the features of organels say that neurons are very productive cells.they syntesize protein and they are anabolic cells.

brain and oxidative stress

Hystopatalogical alterations in brain causes oxidativa stres.Mental distress is an important result of oxidative stress and you know bipolar disorders is one of the mental disorders.recently studies indicated that lithium which treats bipolar disorders decrease oxidative stress in the brain.but this positive effects of lithium can't be seen in other organs.why?what is the mechanism for lithium which working in brain positive contrary to the other organs?

discussing liver and blood testis barrier:we know some cells have duplicated nucleus like liver or muscle cells.but some of us know the liver cells nucleus have 4n,8n.12n e.g chromosomes.we think their nucleus have 2n chromosomes(46) but that is not.you know sperm has n(23) chromosomes and that is advocated that blood testis barrier is protecting sperms from immun system cells.ıf ıt is like that wyh there isn't a system protecting hepatocytes from immun system cells and when we research we see there are fenestreated capilleries not continous capilleries between hepatic cords.the hepatocytes are close to blood for this reason ı think the purpose of blood testis barrier must be for differen cause.

ı haven't written for a long time because ı was on holiday.ı want to give information about pancreas b cells and stem cells.(you know ı am interest in stem cell and ı want my workings to be releated with it.) diabettus mellitus type 1 is widespread dissease in the world.it is an outcome of degenerating b cells in pancreas with auto immun attack.there are many methods applied for treating.one of them is langerhans islets transplantation from cadavra's donor but it has not conclusive solution.ıt provides solution for a period longer than three years indepence of insulin.at the present time the stem cell treatment is promising.there are three ways.one of them is using embryonic stem cell or human stem cell for obtaining insulin secreting cells,the other is reprogramming somatic cells to convert b cells and the other is replication of b cells in vivo or in vitro conditions.

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...

connective tissue derives from mezoderm and mesencyme cells derived from mesoderm.the epitel tissue is avascular.melanocytes are mostly specific to our scin.(whole epitel tissue?)fibroblasts do not go mitosis and they do not dejenerate like other cells.the fibroblasts give rise to fibrocyte and also fibrocyte give rise fibroblasts but the second condition occurs when more fibroblasts are necessary.the ribozomoses in cells are syntesized in nucleolus and cytoplazm.the myofibroblasts have two characteristic feature in sequence first they syntesize collagen fibrils(actin flamanetes) and second they are smooth muscle cells.the smooth muscle cells have gap junctions and this feature is important for their contraction.stable macrophages are not phagocyte but independent macrophages are phagocyte.some macrophages are said hemosiderin-laden macrophages.we saw these macrophages in the respiratory sistem when more blooding occurs.plasma cells are like tears in the sections hemotoxilen-eosin stained and they are watched eosiophilic.in electron microscopic visualing their nucleus seen like car wheel.the nucleus has nucleolous in the center it has mrna and rrna the other hiperchromatic area near the nucleus membran has only dna.

stem cells isolated from fat using for diseases or tissue damage is accessibility and lack of rejection.the fat deriverde stem cells secrete vaso endotelhial growth factor(vegf) and other factors which can inhibit cartilage regeneration.but ıts effect can be neutralized by antibodies.