Ch 16 Neurological Disorders

tumor

mass of uncontrolled aberrant cells, damage brain tissue by either compression or infiltration

malignant tumor

cancerous, can metastasize (spread to other organ systems)

benign tumor

harmless, doesn’t grow beyond its own region

tumor initiating cells

arise from stem cells and rapidly proliferate and give rise to a glioma

cause for malignant tumors metastasizing

types of tumors

1. gliomas

2. ependymomas

3. meningioma

gliomas

derived from glial cells and are highly malignant and fast growing

ependymomas

another type of glioma

meningioma

benign tumor of the meninges

radiation

stereotaxic radiosurgery

laser-induced thermal therapy

heat generated from a laser is directed to ablate tissue

chemotherapy

kills all cells that are dividing, causes hair loss

seizures

sudden excessive aberrant activity of nerve cells which can result from tumors, injury/scar tissue

convulsion

uncontrollable activity of the muscles that is visible to others during a seizure, not all seizures produce convulsions

simple partial seizures

changes in consciousness not a loss of consciousnessc

complex partial seizures

lead to a loss of consciousness

Grand mal seizure (aka tonic-clonic)

generalized, includes motor systems of the brain, includes convulsions

• preceded by auras

• tonic phase; beginning of the seizure: muscles contract, rigid posture, lasts about 15 seconds

• clonic phase: follows tonic- convulsions

causes of seizures

• scarring from brain injury

• some genetic etiology

• drugs or infections that cause a high fever

• withdrawal from GABAergic drugs

  • alcohol, benzodiazepines, barbiturates

treatments for seizures

• treated with anticonvulsant drugs (increase GABA activity)

• surgical removal of scar tissue (psychiatric function improves, despite removal of healthy tissue)

• interictal inhibition: GABA neurons surrounding the focal area of the seizures are suppressing the brain tissue between seizures

hemorrhagic stroke

vessels burst

ischemic strokes

vessels are blocked, cutting off oxygen supply to tissue

thrombus

blood clot formed in vessels- thrombi become too large so blood supply is blocked

embolus

a piece of material that forms in a part of the vasculature, breaks off and is carried through the bloodstream until it lodges in a small artery

closed-head injury

force hits the head

• coup- term for the blow to the head

• countercoup- when the brain bounces back and hits the other side of the skull

open-head injury

(penetrating) object cuts, pierces the skull

Chronic Traumatic Encephalopathy (CTE)

neurodegeneration due to repeated head trauma

• abnormal tau protein accumulates in cortex

• reduced brain volume/enlarged ventricles

Parkinson’s Disease

trouble initiating movement, slow motor responses, resting tremor, abnormal activity of pons, midbrain, cerebellum and thalamus

Lewy Bodies

DA cells that survive may form Lewy bodies which are circular structures found in the cytoplasm of cells.

Lewy body dementia

caused by lewy bodies. type of progressive dementia, severe distress, leads to a decline in thinking, reasoning and independent function

causes of Parkinson’s Disease

• mutation of gene on chromosome 4 will produce the disorder and can be passed down

• Chromosome 4 known mutation produces a toxic gain of function: produces a protein that are toxic to the cell

• Parkin is important- transfers misfolded proteins to proteasomes, organelles that destroy them

• toxins, infections

α-Synuclein

aggregation of misfolded molecules occur in DA neurons

• they accumulate and ultimately kill the cell

Huntington’s Disease

genetic disorder: dominant gene of chromosome 4, mutation is CAG repeats (37-80)

• degeneration of caudate and putamen

• uncontrollable jerky movements

• tissue loss and larger ventricles

Amyotrophic Lateral Sclerosis (ALS)

degenerative disorder that attacks spinal cord and cranial nerve motor neurons

• exaggerated stretch reflexes

• progressive weakness

• muscular atrophy

• paralysis

• cognitive issues with working memory, language, social ability

Multiple Sclerosis: An autoimmune disease

at scattered locations throughout the CNS, the immune system attacks myelin sheaths leaving hard patches of debris = sclerotic plaques

• normal neural transmission is disrupted

MS symptoms

appear, increase in severity, then decrease (remitting-relapsing disorder)

• vision problems

• tingling and numbness

• pains and spasms

• weakness or fatique

• balance problems or dizziness

• bladder issues

• sexual dysfunction

• cognitive problems

Alzheimer’s disease

• severe degeneration of the hippocampus, entorhinal cortex, neocortex, nucles basalis, locus coeruleus, and raphe

• Lewy bodies are often implicated

• progressive loss of memory and other functions

• fail to think or words or names

• increasing confusion and difficulty with tasks

anterograde amnesia

forgetting recent events