Term
| Cross Section of the Brain-Gray matter |
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Definition
Cortex—neuron, support cells
Deep parts of the brain—basal ganglia, thalamus, hypothalamus |
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Term
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Definition
| Beneath the cortex—myelinated axons |
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Term
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Definition
Frontal lobe—motor functions, behavior, emotions, higher intellectual functions
Parietal lobe—sensory functions
Temporal lobe—hearing, smelling
Occipital lobe—visual center
Thalamus—integration of sensory stimuli
Hypothalamus—connects and regulates many body functions |
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Term
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Definition
Midbrain—visual and auditory reflex centers
Medulla oblongata—cardiac, vasomotor, respiratory centers
Pons |
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Term
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Definition
Major regulator of motor activities
Integration of sensory impulses from the spinal cord and vestibular organ and motor impulses from the cerebral cortex |
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Term
| Normal Cells of the Nervous System |
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Definition
Neuron
Perikaryon
Dendrites
Axon
Support cells (glia) |
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Term
| Overview of Major Diseases |
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Definition
Developmental and genetic diseases
Diseases caused by trauma
Circulatory disorders
Infectious diseases
Autoimmune diseases
Metabolic and nutritional diseases
Neurodegenerative diseases of unknown etiology
Brain tumors |
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Term
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Definition
The nervous system consists of highly specialized functional units.
The CNS is protected from mechanical injury by the bones of the skull and vertebrae.
The CNS is separated from the remainder of the body by meninges and by a blood–brain barrier.
The brain and the spinal cord are surrounded by CSF. |
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Term
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Definition
Neurons are nondividing, postmitotic, permanent cells.
Glial cells are facultative, mitotic (labile) cells that are capable of dividing.
The CNS may be affected not only by diseases that involve other organs but also by diseases that are unique to the CNS.
The symptoms of CNS diseases result from dysfunction of or loss of function of neurons. |
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Term
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Definition
Herniation of the cingulate gyrus
Herniation of cerebral uncus
Herniation of cerebral tonsil
Herniation through an opening of a broken skull |
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Term
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Definition
Genetic diseases (e.g., Tay-Sach disease)
Chromosomal abnormalities (e.g., Down’s syndrome)
Intrauterine infections (e.g., TORCH syndrome)
Anencephaly and dysraphic disorders (e.g., meningocele, myelomeningocele, spina bifida) |
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Term
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Definition
Epidural
Subdural
Subarachnoid
Intracerebral |
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Term
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Definition
Between the skull and the dura
Rupture of middle meningeal artery
Coma
Invariably lethal if unrecognized |
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Term
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Definition
Located between the dura and the arachnoid
Most often caused by blunt trauma
Source of bleeding—ruptured bridging veins
Nonspecific symptoms (e.g., headache) caused by increased intracranial pressure |
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Term
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Definition
Located between the arachnoid and the pia layer of the meninges
Caused by:
Traumatic contusion of the brain
Rupture of congenital (berry) aneurysms
High mortality |
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Term
| Intracerebral Hemorrhages |
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Definition
Common complication of head trauma
Rupture of intracerebral vessels
Gunshot wounds
Nontraumatic forms (e.g., stroke)
Common in hematologic diseases (e.g., leukemia) |
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Term
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Definition
Third most common cause of death
Most common crippling disease
Most important clinical manifestation—stroke
Disease of old age (atherosclerosis)
Arterial hypertension
Thromboembolism |
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Term
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Definition
Global ischemia
Cerebral infarct
Intracerebral hemorrhage |
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Term
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Definition
Lacunar infarcts
Watershed infarcts
Laminar necrosis |
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Term
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Definition
Caused by thrombotic occlusion and thromboemboli
Encephalomalacia
Pale infarct or hemorrhagic infarct
Surrounding brain tissue that is edematous
Fluid-filled cavity (“pseudocyst”)
Clinical presentation as stroke (e.g., contralateral hemiplegia, sensory loss, global aphasia, drowsiness, stupor, coma) |
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Term
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Definition
Caused by arterial hypertension
Basal ganglia
Well-circumscribed hematoma
Clinical features possibly resembling those of cerebral infarction |
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Term
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Definition
Brain injury
Brain concussion
Brain contusion
Laceration
Neck and spinal cord injuries
Hyperextension injury
Hyperflexion injury |
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Term
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Definition
Bacterial infections
Hematogenous route or from septic emboli
Caused most often by:
Neisseria meningitidis
Streptococcus pneumoniae
Escherichia coli
Haemophilus influenzae
Treponema pallidum |
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Term
| Infections of the CNS-Viral |
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Definition
Hematogenous route
Measles virus, rubella, adenovirus, herpesvirus, cytomegalovirus, rabies virus |
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Term
| Infections of the CNS-Protozoal |
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Definition
Hematogenous route
Toxoplasma gondii |
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Term
| Infections of the CNS-Fungal |
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Definition
Hematogenous route
Candida albicans, Aspergillus flavus, Cryptococcus neoformans |
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Term
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Definition
Encephalitis
Myelitis
Cerebral abscess
Meningitis
Neurosyphilis
AIDS-related CNS lesions |
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Term
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Definition
Demyelinating disease
Women affected twice as often as men
Genetic factors
Oligoclonal T-cell populations in the brain
IgG in CSF composed of oligoclonal bands |
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Term
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Definition
Chronic disease
Episodes of exacerbation and remission of neurologic symptoms
Sensory abnormalities
Loss of sensitization of touch
Motor abnormalities
Muscle weakness, unsteady gait, incoordination of movements, sphincter abnormalities
Unpredictable course |
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Term
| Metabolic and Nutritional Diseases of the Nervous System |
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Definition
Inborn errors of metabolism
Tay-Sachs disease, Niemann-Pick disease, phenylketonuria
Nutritional disease
Vitamin B1 deficiency (Wernicke-Korsakoff syndrome)
Vitamin B12 deficiency (uncoordinated movements, sensorimotor peripheral neuropathy, signs of spinal cord disease, abnormal gait, psychiatric symptoms)
Nicotinic acid deficiency (dermatitis, diarrhea, delirium)
Alcoholism |
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Term
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Definition
Wernicke-Korsakoff syndrome
Uncoordinated movements
Progressive mental deterioration, loss of memory, inability to concentrate, irritability
Subdural hematoma, pontine myelinolysis
Delirium tremens |
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Term
| Neurodegenerative Diseases |
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Definition
Alzheimer’s disease
Parkinson’s disease
Huntington’s disease
Amyotrophic lateral sclerosis |
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Term
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Definition
Unknown etiology
Genetic factors—Down’s syndrome
Atrophy of the cortical parts of the frontal and temporal parts of the brain
Disease of older people (>70 years)
Dementia—progressive loss of cognitive functions and a functional decline (loss of memory predominates) |
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Term
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Definition
Gross examination
The brain appears atrophic and shows narrowing of the gyri and a widening of the sulci.
Histologic changes
Most prominent in the cortex
Neuritic (senile) plaques
Neurofibrillary tangles
Granulovacuolar degeneration
Deposition of amyloid in the neuritic plaques and the wall of the cerebral vessels |
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Term
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Definition
Subcortical neurodegenerative disorder
Typically affects elderly persons
Cause unknown
Decreased number of dopaminergic neurons in the substantia nigra
Disturbances of movement, primarily tumor, rigidity, bradykinesia, postural instability |
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Term
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Definition
Tremor or twitching of the muscles
Instability while walking
Depression and dementia
Significant number of patients become depressed, and about 10% develop dementia.
Gross examination
Substantia nigra appears pale.
Histologically
Loss of melanin-rich neurons
Lewy bodies |
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Term
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Definition
Autosomal dominant neurodegenerative disease
Involuntary, gyrating movements and progressive dementia
Atrophy of the cortex and subcortical nuclei, most prominently the caudate and putamen |
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Term
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Definition
Nonspecific histologic changes include:
Atrophy, degeneration, loss of neurons, reactive gliosis
First symptoms usually do not appear before midlife.
Most affected patients become mentally incapacitated by the age of 50 to 60 years. |
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Term
| Amyotrophic Lateral Sclerosis |
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Definition
Neurodegenerative disease
Affects older men and women
Motor weakness and progressive wasting of muscles in the extremities (small hand muscles)
Fasciculations (involuntary twitching)
Slurred speech but the intellect is not affected |
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Term
| Amyotrophic Lateral Sclerosis |
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Definition
Loss of motor neurons in the spinal cord, midbrain, and cerebral cortex
Loss of the lateral cerebrospinal pathways in the spinal cord
Incurable, progressive disease that leads to death over a period of a few years |
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Term
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Definition
Brain tumors have a very high mortality rate.
Brain tumors occur at any age.
Of tumors, 50% are primary neoplasms
They may be benign or malignant.
Malignant tumors of the CNS do not metastasize. |
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Term
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Definition
Solid cerebral tumors in adults
Cystic cerebellar tumors in children
Composed of relatively well-differentiated astrocytes
Progress into lesions that are histologically indistinguishable from glioblastoma multiforme |
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Term
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Definition
Most common CNS tumor
Peak incidence—65 years
Lateral hemispheres
Gross appearance
Parts of the tumor are necrotic and yellow
Parts are hemorrhagic red, and parts are white
Irregularly shaped
Poorly demarcated
Butterfly-like appearance |
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Term
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Definition
Histologically
Highly anaplastic astrocytic cells
Cell appearance—may retain a fetal appearance or become enlarged, bizarre shaped, or multinucleated with well-developed cytoplasm
Numerous mitotic figures
Proliferative changes of blood vessels |
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Term
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Definition
Cerebral hemispheres
Middle-aged adults
Well circumscribed, partially cystic, and calcified
Histologically
Well-differentiated oligodendroglia cells
Possible progression to glioblastoma multiforme |
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Term
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Definition
Children—ventricles
Adults—spinal cord
Ependymoma of the filum terminale
Tumor cells line the papillary structures or form rosettes |
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Term
| Tumors of Neural Cell Precursors and Undifferentiated Cells |
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Definition
Medulloblastoma
Cerebellum
Childhood
Uncertain origin
Poor prognosis |
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Term
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Definition
Arise from the meninges
Mostly benign
Located in the midline, at the base of the brain, and along the spinal cord
Epileptic seizures or motor deficits
Excellent prognosis |
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Term
| Tumors of the Cranial and Spinal Nerves |
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Definition
Neuromas
Schwannomas (neurilemomas)
Neurofibromas
Solitary or multiple—mostly benign
Neurofibrosarcomas rare
Neurofibromatosis type II—involves cranial nerve, causing hearing loss and vertigo |
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Term
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Definition
Of all brain tumors, 50% represent metastases.
They may be solitary or multiple.
Most common tumors metastasizing to the brain are:
Lung cancer
Breast cancer
Melanoma |
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