Neurological Disorders Part 1 1 What is the difference b t a benign and a malignant tumor How can each cause brain damage What are metasteses won t regrow Benign Encapsulated so has distinct border region can be cut out and Can still cause damage by compression Malignant Can cause damage through compression and or infiltration Infiltrating tumor invades other regions and destroys cells in its path flow of CSF like image in previous slide Compression of other brain regions can damage cells and obstruct Can give rise to metastases Means that little pieces of the tumors little cells can break off and Metastasizing tumor sheds cells that travel through bloodstream Ex a tumor can originate in the lung but the cell made its way to Malignancy can be caused by rare population of cells called tumor travel throughout the blood and see new tumors in other regions of the brain or other regions of the body the brain This a big prob with malignant tumors and seed new tumors initiating cells main undifferentiated Originate from neural stem cells Self Renewing can go through many cycles of cell division but re Multi potent it can become many many different types of cells Rapidly proliferate glioma And these stem cells can divide and still remain multi potent they can still become many different types of cells w in a tumor Glioblastoma Multiform Malignant brain tumors especially ones that are as More resistant to chemotherapy and radiation Bc this differentiating of these stem cells are occur sociated w these tumor initiating cells rapidly grow ring so quickly 2 What types of cells give rise to brain tumors More specifi cally what types of cells don t give rise to tumors Gliomas and metastatic are most serious tumors Generally ma Glioblastoma Multiformae a lot of glial cells formed by undifferen lignant and fast growing tiated or poorly differentiated glial cells common in children Astrocytoma made by astrocytes Ependymoma ependymal cells that line the ventricles Medullablastoma occur in the roof of the fourth ventricle most Oligodendrocytoma originates from oligodendrocytes Meningioma comes from meninges Pituitary Adenoma comes from cells that make hormones in pitu Neurinoma from schwann cells itary gland Metastatic carcinoma metastatic tumor don t know what cell type it is unless you biopsy it this is something that is going to begin as a malignant tumor in some other part of the body cells are going to break off travel through bloodstream to the brain and see new tumors w in the brain Angioma Comes from cells of blood vessels Pinealoma comes from cells of the pineal gland Pontine Glioma glial cell tumor w in the pons Glioma w in the basal ganglia Ependymoma come from lining of ventricles Ependymal cells along w pia mater and blood vessels form the choroid plexus makes CSF We see this lining in the ventricles and we see a tumor arising from those ependymal cells Neurons are postmitotic so no longer dividing so don t give rise to tumors mors 3 Why are drugs that inhibit angiogenesis used against brain tu Drugs To inhibit angiogenesis tumor needs blood supply secretes en They inhibit the growth of new blood vessels Tumors need oxy dothelial growth factor to induce angiogenesis drug binds to deacti vates growth factor only prolongs life a few months gen glucose all the stuff in the blood to be able to survive If you can inhibit the growth of blood vessels to the tumor you can starve the tumor The tumor cels themselves to create endothelial growth factor to try to bring in new blood vessels to feed them gen erally these drugs block that endothelial growth factor so it can t re cruit new blood vessels Unfortunately these don t do a whole lot to prolong life Of course a lot of research into drugs for cancers and a lot are aimed at those tumor initiating cells or cancer stem cells Need more specific drugs lots of research into how to target tumor initiating cells 4 Understand the different types of seizures Know the differ ence b t generalized and partial and b t simple and complex Know the major features of a grand mal including understand ing the tonic and clonic phases and petite mal seizure Seizures Sudden excessive activity of cerebral neurons If neurons are in motor cortex convulsions occur wild uncontrol Jacksonian march Most seizures don t involve convulsions 2 5 million people in US have seizure disorder lable activity of muscles most seizures don t involve convulsions But however they mani fest convulsion or lack of muscle tone or seeming to not be present for a while the problem in the brain is excessive activity A lot of neural activity that should not be happening Generally only happens w in the cortex Usually cortical cells that are able to undergo this epileptic hormone activity not the deeper brain regions Can manifest in different ways If the cortical neurons that are becoming activated inappropriately are motor cortex then you will see some degree of movement and sometimes it s observed where the seizure begins in one part of motor cortex and then travels along motor cortex Jacksonian March You would see a progression of involvement of parts of the body along the homunculus so the foot is in the midline then you see leg trunk arm fingers eyes face lips tongue and you would see the body moving in that particular order It could be on just one side of the body bc it is just on one side of the brain seizures and there are generalized seizures Then there are types of par tial seizures simple or complex Generally seizures are in a couple diff categories there are partial Partial versus generalized Partial definite focus Usually an old injury or a developmental abnormality there is a place in the brain where the seizure begins often times an area where there was an injury Or a developmental abnormality partial seizures generally begin from specific locus they generally involve smaller region of cortical tissue and generally stay in one hemisphere of the brain Often proceeded by aura just like grand mal seizures two major types simple and com plex One of the big differences btw those two is the level of con sciousness during the seizure Generalized widespread loss of consciousness don t have a clear obvious focus Much more widespread And Absence seizure bc they are so widespread they involve a loss of consciousness Not un common that a partial seizure began from particular focus can evolve into a more generalized seizure three major types petit mal These seizures are characterized by no
View Full Document
Unlocking...