Chapter 10

• A tumor or neoplasm (new growth) is a mass of cells that grow independently of the rest of the body.
• Meningiomas - tumors that grow between the meninges, the three membranes that cover the central nervous system.
• All meningiomas are encapsulated tumors - tumors that grow within their own membrane.
• Benign tumors - tumors that are surgically removable with little risk of further growth in the body.
• Infiltrating tumors are those that grow diffusely through surrounding tissue.
• Gliomas - brain tumors that develop from glial cells.
• Metastatic tumors - tumors that does not originate in the brain. They grow from infiltrating cells that are carried to the brain by the bloodstream from some other part of the body.
• Metastasis refers to the transmission of disease from one organ to another
• Strokes are sudden-onset cerebrovascular disorders that cause brain damage.
• Acoustic Neuromas are tumors that grow on nerves or tracts. They are encapsulated tumors that grow on cranial nerve VIII.
• Infarct - the area of dead or dying tissue produced by a stroke.
• Penumbra - surrounds the infarct ; dysfunctional area.
• Two major types of strokes : those resulting from cerebral hemorrhage and those resulting from cerebral ischemia.
• Cerebral hemorrhage (bleeding in the brain) - occurs when a cerebral blood vessel ruptures and blood seeps into the surrounding neural tissue and damages it.
• Aneurysm - is a pathological balloonlike dilation that forms in the wall of an artery at a point where the elasticity of the artery wall is defective.
• Cerebral ischemia is a disruption of the blood supply to an area of the brain.
• In thrombosis, a plug called a thromubus is formed and blocks blood flow at the site of its formation.
• The three main causes of cerebral ischemia are thrombosis, embolism, and arteriosclerosis.
• Embolism - embolus is carries by the blood from a larger vessel, where it was formed, to a smaller one, where it becomes lodged ; in essence, an embolus is just a thrombus that has taken trip.
• In arteriosclerosis, the walls of blood vessels thicken and the channels narrow, usually as the result of fat deposits ; this narrowing can eventually lead to complete blockage of the blood vessels.
• Two important properties of ischemia-induced brain damage:

  1. It takes a while to develop.
  2. Does not occur equally in all parts of the brain.
• Closed-head TBIs - brain injuries produced by blows that do not penetrate the skull.
• Contusions - are closed-head TBIs that involve damage to the cerebral circulatory system.
• Glutamate - the brain's most prevalent excitatory neurotransmitter, plays a major role in ischemia-induced brain damage.
• Subdural Space - is the space between dura mater and arachnoid membrane.
• Subdural hematoma - puddle of blood
• Contrecoup injuries - the blow causes the brain to strike the inside of the skull on the other side of the head,
• Mild TBI - when there is a disturbance of consciousness following a blow to the head and there is no evidence of a contusion or other structural damage.
• mTBIs were once called concussions
• Chronic traumatic encephalopathy (CTE) is the dimentia (general intellectual deterioration).
• Encephalitis - inflammation from the invasion of the brain by microorganisms (brain infection).
• Two common types of brain infections: bacterial and viral
• Cerebral abscesses - pocket of pus in the brain. Caused when bacteria infect the brain.
• Meningitis - inflammation of the meninges.
• Syphilis - are passed from infected to noninfected individuals through contact with genital sores.
• Rabies - usually transmitted through the bite of a rabid animal.
• Toxic psychosis - chronic mental illness produced by a neurotoxin.
• Tardive dyskinesia (TD) - involuntary smacking and sucking movements of the lips, thrusting and rolling of the tongue, lateral jaw movements, and puffing of the cheeks.
• Endogenous toxins - are produced by the patient's own body.
• Down syndrome - there is an extra chromosome during egg fertilization.