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Flashcards in Nervous System Deck (42)
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Describe the functions of the four major lobes of the brain.

Frontal motor functions, behavior, emotions, higher intellect.

Parietal sensory functions.

Occipital visual center. 

Temporal hearing and smelling.


Compare the functions of the midbrain, pons, and medulla oblongata with that of the cerebellum. 

midbrain, pons, MO = myelinated nerve bundles connecting brain to SC
visual and auditory reflex, cardiac, vasomotor, respiratory centers


cerebellum = sensory input from SC and inner ear to cortex

balance, muscle tone, mvmt coordination


Describe the function of the spinal cord.

anterior horn >> peripheral nerves

- extensions of cortical and subcortical brain neurons

- carry motor impulses 

posterior horn >> spinal ganglia

- carry sensory input


Describe the circulation of the cerebral spinal fluid.

Produced by choroid plexus in 3rd ventricles.  Flows at low pressure lateral ventricles >> 3rd V >> 4th V >> lateral openings + median opening >> central canal of SC


List the main cells of the nervous system. 

Glial cells (support) = astrocytes, oligodendroglia, microlia, ependymal



What are the most important diseases of the nervous system.

  • Developmental and genetic diseases
  • Diseases caused by trauma
  • Circulatory disorders
  • Infectious diseases
  • Autoimmune diseases
  • Metabolic and nutritional diseases
  • Neurodegenerative diseases
  • Brain tumors


What are the sites of brain herniation caused by intracranial hypertension?

Subfalcine herniation: cingulate gyrus protrudes beneath the falx cerebri

Transtentorial herniation: uncus protrudes tentorium cerebelli

Tonsillar hernation: cerebellar tonsils protruding into the foramen magnum


List the main dysraphic disorders of the CNS and describe their pathogenesis.

Incomplete fusion of the neural tube >> dysraphic disorders

anencephaly calvaria not formed

meningocele meninges protrude through defect

myelomeningocele protrusion of meninges + SC

spina bifida absence of vertebral arches


List the most important intracranial hemorrhages and describe their causes

Epidural hematoma usually from fracture, rupture of middle meningeal artery, lethal

Subdural hematoma tearing of thin-walled veins, accumulation over lateral hemispheres

Subarachnoid hemorrhages ruptured aneurysms, typically at the base of the brain, may be preceded by HTN

Intracerebral head trauma, stroke, hematologic disease


What is stroke?

Ischemic (85%)

or hemorrhagic (15%)



What is global cerebral ischemia, and what are its consequences?

Widespread atherosclerotic narrowing over entire cerebrovascular system

small lacunar infarcts >> multi-infarct dementia



What is the pathogenesis of "watershed infarcts" and laminar necrosis of the brain?

Watershed infarcts: hypoperfusion of the marginal zones between arteries (carotid and basilar)

Laminar necrosis: hypoperfusion of deeper zones of gray matter that receive blood from penetrating arteries


Describe the pathology of cerebral infarcts.

Thrombotic occlusion >> infarct

ischmic brain = liquefactive necrosis = encephalomalacia

- pale or hemorrhagic (more common with arterial thrombi)

infarct becomes pseudocyst



Correlate the pathology of intracerebral hemorrhage with the clinical features of the disease.

Most common site: basal ganglia

infarct >> pseudocysts with wall of  hemosider laden macrophages

Basal ganglia: hemiplegia, hemiparesis

Cerebellar: nausea, vomiting, loss of balance, HA

Pontine: death


What are the main pathologic findings after brain injury?

Concussion: transient LOC, NO significant brain changes

Contusion: bruise, hemorrhagic coup and contercoup lesion

Laceration: open trauma, neurologic deficit


Compare hyperextension and hyperflexion injuries of the cervical spine.

hyperextension - rupture of anterior spinal ligaments, compression of posterior SC

hyperflexion - compression of anterior SC


Compare bacterial and viral infections of the CNS


Spread: sepsis, bacteremia, septic emboli, open wounds, sinus infection, inner ear infection
*Strep pneumoniae causes most cases of bacterial meningitis in adults

Spread: hematogenous spread

*herpes = most common viral cause of localized encephalitis in the US


What are prions?

Prions = small infectious particles composed of proteins

*do not contain dna/rna


List the most important protozoal and fungal causes of opportunistic diseases of the CNS.

Protozoal: toxoplasmosis (neonates, AIDs)


Fungal: candida, aspergillus, cryptococcus (AIDs)


Compare the pathology of encephalitis and meningitis.

encephalitis = localized or diffuse inflammation of brain parenchyma

usually virus invades neural or glial cells

meningitis = inflammation of the meninges


Describe the features of neurosyphilis.

- usually presents as chronic meningitis

- meninges: infiltrated with lymphocytes and plasma cells (small BV)

- perivascular inflammation >> cortical ischemia

- tabes dorsalis = atrophy of dorsal (sensory columns)


What are the most important AIDS-related CNS lesions?

HIV infects macrophages and T lymphocytes, and these cells "import" the virus to the CNS


toxoplasma, cryptococcus


What is MS?

An autoimmune demyelinating disease

W > M, 20-45 y/o


Correlate the pathologic features of MS with the clinical signs and symptoms of this disease.

Presence of IgG oligoclonal bands >> responding to antigen?

- Typically involves white matter >> both sensory and motor abnormalities

- Periventricular plaques (lateral hemispheres)

- early lesions = lymphocytes and foamy macrophages

- late lesions = demyelinated axons and reactive astrocytes (gliosis)


How do inborn errors of metabolism affect the CNS?

Tay-Sachs = deficiency of hexosaminidase A >> accumulation of gangliosides

Neimann-Pick = deficiency of sphingomyelinase >> accumulation of sphingomyelin >> atrophy


What is the cause and what are the signs of Wernicke-Korsakoff syndrome?

Thiamine deficiency!

Wernicke's = ocular, gait, mental

Korsakoff's = amnesia, confabulation

hypothalamus, periaqueductal region (midbrain), mamillary bodies


How does alcohol affect the brain?

  • Dementia (atrophy of gyri)
  • Dilated ventricle
  • Wernicke-Korsakoff syndrome
  • Pontine myelinolysis (r/t vigorous Na correction)
  • Myelopathy
  • Neuropathy
  • Myopathy
  • Subdural hematoma
  • Cerebellar atrophy


What are the most important neurodegenerative diseases?

Alzheimers >> frontal/occipital cortex

Huntingtons >> frontal cortex and basal ganglia

Parkinsons >> substantia nigra

ALS >> motor neurons in anterior horn of SC, brainstem, frontal cortex


What is Alzheimer's disease, and how is it diagnosed?

Clinical diagnosis based on demonstration of progressive dementia (excluding other causes)


Describe the macroscopic and microscopic pathologic findings in Alzheimer's disease.

Chromosome's 21 &19 >> APOE4 (19) mutation >> beta amyloid= extracellular

hyperphosphorylation of tau protein >> axonal microtubule binding = intracellular

Brain is atrophic, neuritic plaques, neurofibrillary tangles, deposition of amyloid (see with silver impregnation and congo red stain)