Problem 9 Flashcards
Tumor
a mass of cells whose growth is uncontrolled and serves no useful function
–> damages by infiltration + compression
Malignant tumor
harmful tumor / cancerous
–> no distinct border between mass of tumor cells + surrounding tissue (hard to remove)
Benign tumor
harmless tumor / encapsulated
–> distinct border between the mass of tumor cells + surrounding tissue (easy to remove)
Metastases
shed cells which then travel through the blood stream
–> serve as seeds for the growth of new tumors in different locations of the body
=> form of malignant tumor
Glioma
Brain tumors that arise from glial cells and infiltrate brain substance
–> originate from transformations of neural stem cells
Seizure
period of sudden excessive activity of cerebral neurons
–> nearly all genes that play a role in seizures control ion channels
–> cause damage to the hippocampus due to an excessive loss of glutamate
Convulsion
uncontrollable activity of the muscles
Generalized seizures
widespread, involve most of the brain
Absence seizure
Petit mal
type of generalized seizure, very brief seizures - hard to detect
ex.: kind das in die ferne starrt
Grand mal
type of generalized seizure that occurs in 2 stages
- Tonic phase: all muscles contract forcefully which leads to unconsciousness of the person
- Clonic phase: muscles begin trembling, jerk convulsively –> after some time they relax
Partial seizures
source of irritation is a specific brain region
Simple partial seizures
cause a change in consciousness
Complex partial Seizures
cause a loss of consciousness
Stroke
derives from a variety of vascular disorders
Hemorrhagic stroke
Cerebral Hemorrhage
caused by bleeding within the brain
–> blood seeps in surrounding blood tissue, damaging it
Ischemic Stroke
- block a blood vessel and obstruct the blood flow
–> caused by thrombi and emboli
Thrombus
blood clot that forms in blood vessels
Embolus
formed in one part of the vascular system,
–> carried through blood stream + passes through too small arteries
=> obstructs blood flow
Ischemic Stroke
Process
- Interruption of the blood supply to a specific brain region leads to a depletion of oxygen and glucose
- Sodium potassium pump stops functioning
- Neural membranes become depolarized
- -> excessive release of glutamate - Activation of glutamate receptors leads to
- -> increase of Na+ ions
- -> absorption of huge amounts of Ca+
=> presence of Na+ and Ca+ = toxic
- Intracellular Na+ causes cell to absorb water (cells swell)
- Swell –> activates microglia which become phagocytic (Fresszelle)
- microglia destroys injured cells
- Damaged mitochondria produces free radicals
Penetrating Brain Injury/Open Head Injury
Dura mater + skull is breached/injured
Closed head injury
Skull + dura mater remain intact
Coup
“Blow”
The injury to the brain that occurs in the area of direct impact
Contrecoup
“Counterblow”
The pressure of the blow might push the brain against the opposite side, causing an additional bruise
Parkinsons disease
- Degenerative disorder
–>deficiency of automatic, habitual responses due to damage to basal ganglia
–> patients have almost no nigrostriatal dopaminergic neurons (surviving neurons contain lewy bodies)
Symptoms of Parkinson’s
- resting tremor
- postural instability
- muscular rigidity
Akinesa
difficulty in initiating movement
–> decreased activity of the supplementary Motor area
Where do tremors come from ?
result from abnormalities in
- -> pons
- -> cerebellum
- -> midbrain
- -> thalamus
Causes of Parkinsons
–> mutation of a gene on chromosome 6 that produces a gene called parkin
this mutation permits a high level of defective proteins to accumulate in dopaminergic system + damage its neurons
–> mutation of a gene that produces a-synuclein
this mutation produces a toxic gain of function
Parkin
gene, transfers defective proteins to proteasomes which in turn destroy these defective proteins
Dementia
acquired and persistent syndrome of intellectual impairment
Cause of Dementia
accumulation of defective proteins
ex.: tau proteins, a-synuclein
Paralimbic System
undergoes most severe changes
–> especially entorhinal cortex which is affected the earliest and most severely
Entorhinal cortex
Major relay through which information flows from neocortex to hippocampus
- as neocortex is degenerated, information doesn’t arrive at hippocampus => memory loss
- part of paralimbic system
Regions that are damaged the most as a result from Dementia
- neocortex
- paralimbic system
Regions that are spared from dementia
- brainstem
- cerebellum
- spinal cord
Hemathoma
solid swelling of clotted blood within the tissues
Arteriosclerosis
- thickening, hardening, and loss of elasticity of the walls of arteries
- occurring typically in old age
–> restricts blood flow to organs and tissues
Meningiomas
Tumors that grow between the meninges
- originates mostly in dura mater
–> most benign brain tumor
