Disorders of the neurological system (including Disorders of Circulation within the CNS)

consists of brain and spinal cord

what makes up the central nervous system?

• contained entirely within the CNS

• usually relays from afferent to efferent

what are association neurons?

cranial and spinal nerves

what makes up the peripheral nervous system (PNS)?

• in the PNS

• dendrites distal to CNS and axons proximal

what are afferent (sensory) nerves?

• in the PNS

• dendrites proximal to CNS and axons distal

what are efferent (motor) nerves?

brain tumors

space-occupying lesions that cause increase in intracranial pressure

true

t/f: primary malignant tumors rarely metastasize outside the CNS

• not well-defined

• invasive and have irregular projections into adjacent tissue

• usually inflammation

describe primary malignant brain tumors

• seizures

• face paralysis

• vomiting

• etc.

signs and symptoms of brain tumors

haemophiles influenzae bacteria

meningitis in young adults is most often due to _________

streptococcus pneumonia

meningitis in older adults is most often due to _________

• photophobia

• nuchal rigidity

• bruszinski sign

name some signs and symptoms of meningitis

occurs when bacteria or fungi enter the brain tissue after an infection or severe head injury. pus filled swelling in brain

• localized infection

what is a brain abscess?

encephalitis

infection of the parenchymal (nerve or glial cells) or connective tissue of the brain and spinal cord

true

t/f: encephalitis results in permanent damage

severe headache, stiff neck, lethargy, vomiting, seizures, fever

name early signs of encephalitis

concussion

• reversible interference with brain function

• cause sudden excessive movement of brain

contusion

• bruising of brain tissue

• blunt blow to the head

closed head injury

• skull not fractured in injury

• brain tissue injured and blood vessel may be ruptured

• extensive damage may occur when head rotated

depressed skull fractures

• involve displacement of a piece of the bone below the levels of the skull

• compression of brain tissue

basilar fractures

• occur at the base of the skull

• leakage of CSF possible thru ears or nose is possible

• when forehead hits windsheild

contrecoup injury

• area of the brain contralateral to the site of direct damage is injured, as brain bounces off skull

1. laceration of nerve tissue by bone fragments or complete transection or crushing of cord

2. partial transection or crushing of cord or bruising

3. prolonged ischemia and necrosis

name the 3 main ideas related to spinal cord injuries

hydrocephalus

excess CSF accumulates at skull (more production than reabsorption)

1. non-communicating: flow is blocked

2. communicating: problem on absorption on CSF thru subarachnoid villi

name and describe the 2 types of hydrocephalus

multiple sclerosis

progressive demyelination of the neurons in the brain spinal cord and cranial nerves- autoimmune

20-40 y/o

when is the onset of MS?

1. cigarette smoking

2. caffiene intake

3. high blood urate levels

what 3 things put you at decreased risk for developing parkinsons disease?

parkinsons

a depletion of glutathione and increase in iron levels can indicate what disease?

• lewy bodies present

• overactivation of microglia (inflammation)

• mitochondrial dysfunction

describe parkinsons disease

huntingtons disease

• progressive, incurable brain disease

• autosomal dominant inhereted

• causes uncontrolled involuntary movements

• ages 35-44 years

• mean of 19 years

what age range is the onset of symptoms for huntingtons disease? what is the mean duration?

huntingtons disease

this disease pathology includes:

• shrinkage of brain (in volume)

• gross atrophy in caudate nucleus

amyotrophic lateral sclerosis (ALS)

a progressive neurodegenerative disease that causes weakness, disability, and death within 3-5 years

seizure disorders

abnormal electrical discharges within brain that result in involuntary movement and/or behavior and sensory alterations

tonic phase

what phase of seizure is this?

• 15-60 secs

• muscular rigidity

• sudden LOC

• hypoxia

• inc metabolic demand

clonic phase

what phase of seizure is this?

• 60-90 secs

• alternating muscular contraction and relaxations

• hyperventilation

• eyes roll back, froth at mouth

postictal period

what phase of seizure is this?

• dec LOC; sleepy

• quiet and relaxed breathing

• gradual regaining of consciousness

ischemia

• obstructed blood vessels

• drop in blood flow to brain

hematoma

a collection of blood that pools outside of a blood vessel, typically caused by an injury that damages a blood vessel

1. hematoma

2. excessive CSF production

3. blockage of duct system conveying CSF

inc pressure within skull causes what 3 things?

2.5 ; 15

the brain is ___% of total body mass and recieves ___% of cardiac output

60

white matter of brain is ____ % of brain mass

• right and left internal carotid arteries

• right and left vertebral arteries

what arteries are involved in cerebral circulation?

choroid plexi of ventricles

where is CSF produced?

• ventricular system of brain

• subarachnoid space surrounding brain and spinal cord

where does CSF flow through?

via arachnoid villi

how is CSF reabsorbed into venous dural sinuses?

blood-brain barrier

specialized endothelium present in brain capilaries

permits selective entry of substances

• tight junctions between endothelial cells

• few pinocytotic cesicles

• active transport

describe the blood-brain barrier

• highly lipophilic substances cross directly

• most nutrients cross barrier by facilitated diffusion

what substances cross the blood brain barrier

• subfornical organ and area postrema of brainstem

• infundibulum of hypothalamus and pituitary glan

what regions of the brain lack blood-brain barrier?

mechanism that maintains steady flow of blood to brain and spinal cord

what is cerebral autoregulation?

inc. bp = constricted capillaries

dec. bp = dilated capillaries

(increased/decreased) blood pressure = (constricted/dilated) cerebral capillaries

dec PaCO2 = constricted vessels

inc PaCO2 = dilated vessels

(increased/decreased) PaCO2 levels = (constricted/dilated) vessels

compensatory relationship maintaining cerebral compliance in response to changes in volume

what is the monro-kellie hypothesis?

these 3 things indicate what?

• cytotoxic edema

• vasogenic edema

• clearence of brain tissue swelling

• leads to infarction and tissue death

• anaerobic glycolytic pathways initiated

mitochondria dysfunction leads to what?

• cells unable to maintain negative membrane potential

• glutamate and influx of calcium ions

energy deprivation and loss of ion homeostasis leads to what?

• immune cells activated

• leukocytes enter brain

what are some effects of cerebral hemorrhage in sepsis?

transient ischemic attack

temporary episode of neurologic dysfunction when there is a clot blocking blood supply to reigon of brain

focal brain, spinal cord, or retinal ischemia without acute infarction

what causes transient ischemic attack?

stroke

interruption in blood supply to region of brain or bleeding of vessel resulting in brain tissue damage or infarction

87 ; 13

ischemic stroke: ___%

hemorrhagic stroke: ___%

ischemic stroke

partial or complete occlusion of cerebral blood flow due to thrombus or embolus

1. internal carotid

2. middle cerebral

3. basilar

thrombotic strokes effect what 3 arteries?

hemorrhagic stroke

bleeding into brain from bursted blood vessel

ischemic and hemorrhagic strokes

what is this a clinical manifestation of:

sudden onset of focal neurologic deficit persisting at least 24 hrs due to reduction or occlusion of cerebral circulation or rupture of blood vessels

subdural hematoma

bleeding from bridging veins between dura mater and arachnoid membrane

• trauma from high speed impact to skull

• spontaneous

• acute: bleeding immediatley after injury

• chronic: brain atrophy

describe the patho of subdural hematoma

false- its rare

t/f: hemorrhage of spinal cord is common

• sudden, severe back pain w or w/o radiculopathy

• neck stiffness

• photosensitivity

name clinical manifestations of spinal cord hemorrhage