chapter14

Neurological DisordersChapter 14

Learning Objectives

Discuss the mechanism of action of each of the major categories of neurological disorders.

Discuss the causes, symptoms, and treatment of brain tumors, seizure disorders, and cerebrovascular accidents.

Discuss developmental disorders resulting from toxic chemicals.

Discuss the causes, symptoms, and potential treatments for the brain degeneration caused by Alzheimer’s disease.

Neurological Disorders

Neurological disorders are disorders affecting the nervous system central or peripheral

Hundreds of identified disorders Tumors Seizure Disorder Cerebrovascular Accidents Disorders of Development Degenerative Disorders Disorders Caused by Infections Diseases

Tumors

Mass of cells whose growth is uncontrolled and has no function

Mechanisms of tumor damage Compression (benign and malignant) Infiltration (malignant)

Develop from cells which are able to divide Meningiomas Glioma neruoma

Types of Tumors

Malignant Cancerous Infiltrates

surrounding tissue

Benign “harmless” encapsulated

border

Seizure Disorders

Seizure period of sudden, excessive activity of

cerebral neurons Brain damage

hippocampal damage ▪ 50%

Excessive glutamate release

Causes of seizures

Scarring most common stroke, injury, brain abnormality, or

tumor Drugs

withdrawal ▪ alcohol or barbiturate

Infections that cause high fevers Genetic factors

Seizure First Aid

Stay calm Prevent injury Pay attention to the length of the seizure Make the person as comfortable as possible Keep onlookers away Do not hold the person down Do not put anything in the person's mouth Do not give the person water, pills, or food until

fully alert If the seizure continues for longer than five

minutes, call 911 Be sensitive and supportive, and ask others to do

the sameFrom: http://www.epilepsy.com/epilepsy/firstaid

Cerebrovascular Accidents (Stroke)

Hemorrhagic stroke Obstructive stroke

Disorders of Development

Genetic and environmental causes Toxic chemicals Mental retardation can result from

toxin exposure during fetal development

Toxins from viruses and drugs can impair fetal development

Fetal Alcohol Syndrome

Fetal alcohol syndrome

Critical Periods Neural tube complete by 28th day Neuronal porliferation (2-4 months) Migration (3-5 months) Gyri and sulci formation (5-9 months) Myelination (6 months – after birth)

Alcohol may interfere with neural adhesion protein

Degenerative Disorders

Disorders causing a progressive loss of structure or function in the nervous system Not attributed to normal aging

Alzheimer’s disease

Form of dementia Loss of cognitive abilities

Progressive memory loss resembling anterograde amnesia

Severe degeneration of the several brain regions hippocampus, entorhinal cortex,

neocortex, nucleus basalis, locus coeruleus, raphe nuclie

Alzheimer’s disease

Brain pathology

Neuritic plaques extracellular Beta-amyloid

protein

Neurofibrillary tangles intracellular tau proteins

Alzheimer’s disease

Causes of Alzheimer’s Disease

Heredity Some forms run in families Gene for apolipoprotein E (apoE)▪ E4 allele increases risk for late-onset

Sporadic Most cases

Protecting Against AD

Engaging in cognitively challenging tasks Positive correlation between years of

formal education and cognitive performance ▪ Even in individuals with plaques

In mice, training on a new task slowed the accumulation of beta amyloid

Maintain a generally healthy lifestyle