lecture 19 Flashcards
what are the types of TRAUMATIC BRAIN INJURY
close head injury
and open head injury
what is Closed-Head Injury
Caused by a blow to the head with a blunt object
The brain comes into violent contact with the inside of the skull (coup)
The brain then recoils in the opposite direction and smashes against the skull again (contrecoup)
what are Open Head Injuries
Penetrating brain injuries (also called open head injuries) obviously cause damage to the portion of the brain that is damaged by the object or the bone
In addition, damage to blood vessels can deprive parts of the brain of their normal blood supply
Accumulation of blood within the brain can cause further damage by exerting pressure within the brain
explain how Traumatic brain injury (TBI) is a serious health problem
In the United States, approximately 1.4 million people visit an emergency room for TBI, 270,000 people are hospitalized, and 52,000 people die from it.
• Almost a third of deaths caused by injury involve TBI.
• In survivors, scarring often forms within the brain, around the
sites of injury, which increases risk of developing seizures.
• Many people receive brain injuries but are not diagnosed. Even mild cases of TBI (mTBI) greatly increase a person’s risk of developing brain problems down the road. For example, the likelihood of Alzheimer’s disease is much higher in a person who has received blows to the head earlier in life
Seizures have many causes, explain them
Most common cause is
scarring, which may be produced by an injury, a stroke, a developmental abnormality in the brain, or the irritating effect of a growing tumor
Other causes are high fevers (especially in young children) and withdrawal from GABA agonists, such as alcohol and barbiturates
Seizures can also cause brain damage, probably on account of the excessive release of what
glutamate
Although there are some genetic factors that can promote seizures, most seizure disorders are caused by what
nongenetic factors.
define idiopathic
(of unknown causes, or literally one’s own suffering)
Although there are some genetic factors that can promote seizures, most seizure disorders are caused by nongenetic factors.
In the past, many cases were considered to be what
idiopathic
what is Seizure disorder
Preferred term for epilepsy
Sometimes, if neurons that make up motor system are involved, a seizure can cause a convulsion, which is wild, uncontrollable activity of the muscles
do all seizures cause convulsions
not all seizures cause convulsions; in fact, most do not
define Convulsion
Violent sequence of uncontrollable muscular movements caused by seizure
what is a Partial seizure
Seizure that begins at a focus and remains localized, not generalizing to rest of brain
what are the two kinds of partial seizures
A simple partial seizure
A complex partial seizure
what is A simple partial seizure
is a seizure that does not produce loss of consciousness.
what is
A complex partial seizure
is a seizure that produces a loss of consciousness
what is a Generalized seizure
Seizure that involves most of the brain (non- localized seizure).
Includes tonic-clonic seizures, atonic seizures, and absence seizures
what are the parts to a GRAND MAL SEIZURE
Aura
Tonic- clonic seizure
Tonic phase
Clonic phase
define Aura
Sensation that precedes a seizure. Its exact nature depends on the location of the seizure focus
define Tonic- clonic seizure
generalized, grand mal seizure that typically starts with an aura that is followed by a tonic phase and then a clonic phase. This type of seizure involves convulsions
define Tonic phase
First phase of tonic-clonic seizure, in which all of patient’s skeletal muscles are contracted
define Clonic phase
Second phase of a tonic-clonic seizure, in which patient shows rhythmic jerking movements
aka convulsions
who is especially susceptible to seizure disorders
Children
Children are especially susceptible to seizure disorders
• Many do not have tonic-clonic episodes but instead have what
very brief seizures that are referred to as spells of absence.
what are Absence seizures
generalized complex seizures.
what is another name for absence seizures
petite mal seizures
During absence seizures (also known as petite mal seizures), what happens
people stop what they are doing and stare off into the distance for a few seconds, often blinking their eyes repeatedly
Seizure disorders are treated with what
anticonvulsant drugs, such as benzodiazepines, many of which work by increasing effectiveness of inhibitory synapses
Most seizure disorders respond well enough to medications that the patient can lead a normal life
• In a few instances drugs provide little or no help and the seizure foci remain so irritable that what treatment is required
brain surgery is required
what is a Tumor
Mass of cells whose growth is uncontrolled and that serves no useful function
what are the types of Tumor
Non-malignant tumor
Malignant tumor
what is a Non-malignant tumor
Noncancerous, “benign” tumor. Has distinct border and cannot metastasize
what is a Malignant tumor
Cancerous (literally, “harm-producing”) tumor. Lacks distinct border and may metastasizewhat
what is Metastasis
Process by which cells break off of a tumor, travel through the vascular system, and grow elsewhere in the body
The major distinction between malignancy and non-malignancy is what
whether the tumor is encapsulated
what is encapsulated
whether there is a distinct border between the mass of tumor cells and the surrounding tissue
The major distinction between malignancy and non-malignancy is whether the tumor is encapsulated, whether there is a distinct border between the mass of tumor cells and the surrounding tissue
• If there is such a border, the tumor is what
non-malignant; the surgeon can cut it out, and it will not regrow
However, if the tumor is cancerous it grows how
by infiltrating the surrounding tissue, and there will be no clear-cut border between tumor and normal tissue
When surgeons remove malignant tumors is the cancer gone forever
When surgeons remove malignant tumors, some cancer cells are often missed, and these cells will produce new tumors
why kind of tumor can produce neurological symptoms and threaten the patient’s life
Any tumor growing in the brain, malignant or benign
Tumors damage brain tissue by two means:
compression and infiltration
Even a benign tumor occupies space and thus pushes against the brain
Compression does what
can directly destroy brain tissue, or it can do so indirectly by blocking flow of cerebrospinal fluid and causing hydrocephalus
what is Gliomas
Glioma is an example of a malignant brain tumor. The tumor initiating cells originate from the neural stem cells that make glia. They rapidly proliferate and are more resistant to chemotherapy and radiation than most tumor cells. The survival rate from malignant gliomas is very low
what is Meningioma
an example of a non-malignant (encapsulated) tumor.
It is composed of cells that constitute the meninges – the dura mater or arachnoid membrane – often right between the two cerebral hemispheres.
how likely is it to have a stroke
Incidence of strokes in the United States is approximately 750,000/year.
The likelihood of having a stroke is related to age – probability doubles each decade after 45 years of age and reaches 1–2 percent per year by age 75
what are the 2 types of strokes
Hemorrhagic stroke
Ischemic stroke
what is Hemorrhagic stroke
Cerebrovascular accident caused by the rupture of cerebral blood vessel
what is Ischemic stroke
Cerebrovascular accident caused by occlusion of a blood vessel. 87% of strokes are ischemic.
what is an example of CEREBROVASCULAR ACCIDENTS
Atherosclerosis
what is Atherosclerosis
Process in which linings of arteries develop a layer of plaque, deposits of cholesterol, fats, calcium, and cellular waste products. Risk factors include high blood pressure, cigarette smoking, diabetes, and high blood levels of cholesterol.
Precursor to heart attacks (myocardial infarction) and ischemic stroke, caused by clots that form around atherosclerotic plaques in cerebral and cardiac blood vessels
Atherosclerotic plaques often form where
in the internal carotid artery
what does the internal carotid artery do
supplies most of the blood flow to the cerebral hemispheres
Plaques can cause what
severe narrowing of interior of artery, greatly increasing the risk of a massive stroke.
what are the types of strokes
Thrombus
Embolus
what is Thrombus
Blood clot that forms within a blood vessel, which may block it and reduce blood flow to the affected area
what is Embolus
Piece of matter (such as a blood clot, fat, or bacterial debris) that dislodges from its site of origin and occludes an artery. In the brain, an embolus can lead to a stroke
Strokes may produce permanent brain damage
• Depending on wat
size of the affected blood vessel, amount of damage can vary from negligible to massive
During a stroke it might be expected that neurons do what
simply starve to death because they lose their supply of glucose and of oxygen to metabolize it
research indicates that the immediate cause of neuron death is the presence of what
excessive amounts of glutamate
Researchers have sought ways to minimize amount of brain damage caused by strokes
• One approach has been to do what
administer drugs that dissolve blood clots in an attempt to reestablish circulation to an ischemic brain region
• This approach has met with some success. For example, administration of a clot-dissolving drug called tPA (tissue plasminogen activator) after the onset of a stroke has clear benefits, but only if it is given within three hours.
Common cause of intellectual disability is what
the presence of toxins, viruses, and drugs during pregnancy that
impair fetal development. For example, the rubella virus alters brain development.
Alcohol use during pregnancy does what
can have both mild and serious complications. For example, babies born to alcoholic women are typically smaller than average and develop more slowly. Some babies are born with a serious condition known as fetal alcohol syndrome
what is Fetal alcohol syndrome
Birth defect caused by ingestion of alcohol during pregnancy, especially during the third to fourth week;
includes characteristic facial anomalies and faulty brain development that produces often severe intellectual disabilities.
what are Inherited Metabolic Disorders
Several inherited errors of metabolism can cause brain damage or impair brain development
• Errors of metabolism are genetic abnormalities in which recipe for a particular protein is in error. Typically the cause is that an enzyme is not synthesized.
• If the enzyme is a critical one, results can be very serious
re are hundreds of different inherited metabolic disorders that can affect development of the brain. give two examples:
Phenylketonuria (PKU)
Tay-Sachs disease
what is Phenylketonuria (PKU
Hereditary disorder caused by the absence of enzyme that converts the amino acid phenylalanine to tyrosine
Accumulation of phenylalanine causes brain damage unless a special diet is implemented soon after birth
what is Tay-Sachs disease
Heritable, fatal, metabolic storage disorder
Lack of enzymes in lysosomes causes accumulation of waste produces and swelling of cells of brain
Down syndrome is caused by what
not by inheritance of a faulty gene but by possession of extra twenty-first chromosome
is Down syndrome hereditary
Down syndrome is congenital, which does not necessarily mean hereditary
Congenital refers to what
a disorder that one is born with.
list some DISORDERS CAUSED BY INFECTIOUS DISEASES
Encephalitis Meningitis Polio (acute anterior poliomyelitis) Rabies Herpes simplex virus
what is Encephalitis
Inflammation of the brain caused by infection (bacterial or viral), toxic chemicals, or allergic reaction
The first symptoms are headache, fever, and nausea
what is Meningitis
Inflammation of meninges caused by viruses or bacteria
The first symptoms are headache and stiff neck
wha is Polio
acute anterior poliomyelitis
Viral disease that destroys motor neurons of the brain and spinal cord
wha is Rabies
Fatal viral disease that causes brain damage; usually transmitted through the bite of an infected animal
what is Herpes simplex virus
Virus that normally causes cold sores near the lips but can also cause brain damage
what is Multiple sclerosis (MS)
Autoimmune demyelinating disease
• At scattered locations within the central nervous system, myelin sheaths are attacked by the person’s immune system, leaving behind hard patches of debris called sclerotic plaques
• Normal transmission of neural messages through demyelinated axons is interrupted
• Because the damage occurs in white matter located throughout the brain and spinal cord, a wide variety of neurological disorders are seen
can Symptoms of multiple sclerosis go through cycles
Symptoms of multiple sclerosis go through cycles where they flare up and then decrease after varying periods of time
Symptoms of multiple sclerosis go through cycles where they flare up and then decrease after varying periods of time
• In most cases, this pattern (remitting-relapsing MS) is followed by what
progressive MS later in course of disease
what is Progressive MS
characterized by a slow, continuous increase in symptoms of disease.
Multiple sclerosis usually occurs in who
people in their late twenties or thirties and afflicts women somewhat more frequently than men
People who spend their childhood in places far from equator are more likely to come down with disease than are those who live close to equator. It is likely that some disease contracted during childhood spent in region in which virus is prevalent causes person’s immune system to attack his or her own myelin
Only two treatments for multiple sclerosis have shown promise:
First is interferon b,
Another partially effective treatment is glatiramer acetate
what does First is interferon b, do
a protein that modulates responsiveness of the immune system
what does glatiramer acetate do
Another partially effective treatment is glatiramer acetate (also known as copaxone or copolymer-1)
