W4 D3 - Neuro A&P Flashcards
What are the 3 classifications of the neurons?
SAME - sensory afferent motor efferent
Afferent /sensory - carries signalstowards the brain
Efferent / motor - away from the brain
Interneurons - connects neurons within the nervous system
Differentiate spinothalamic tracts vs. corticospinal tracts
Spinothalamic tracts
* ascending sensory tracts
Corticospinal tracts
* descending motor tracts
What are the functions & potential deficits associated with cranial nerves oculomotor 3, glossopharyngeal 9, vagus 10?
Occulomotor
* raises eyelid, eye movement, 4/6 directions
* pupil constriction
Glossopharyngeal
* gag, swallowing, pronation
Vagus
* swallowing, speech issues
What are the main functions of the cerebral lobes?
& their possible major deficits
Frontal
* motor cortex
* high level cognitive functions
Parietal
* top middle of the brain
* sensory perception
Temporal
* side lobes
* hearing and memory
* understanding writen and spoken language
Occipital
* back/base of the skull
* visual perception
What are the main functions of the cerebellum & brainstem?
& their possible major deficits
cerebellum
* controls fine movement to maintain balance
* deficits: gait issues, ataxia, dysmetria (uncoordinated movement)
Brainstem (midbrain, pons, medulla)
* Reticular activating system RAS = altered levels of consciousness
Midbrain
* motor functions
* relay station between brain hemispheres, cerebellum, spinal cord
Pons
* controls respiratory patterns
Medulla
* major centers affecting vital signs
* extends through foramen magnum and becomes spinal cord
What are the characteristics of the meninges?
Dura mater
* periosteal layer - outer tough layer
* meningeal - inner layer
Arachnoid membrane
* mid layer
* CSF flows through
Pia mater
* vascular membrane is tightly adhered to brain surface
finish
What is the purpose of the meninges?
Outline the path of cerebrospinal fluid from production, through the ventricular system to reabsorption
Produced in choriod plexus
Lateral ventricles
Through foramina of monro/ interventricular foramen
into third ventricle
through cerebral aqueduct
into fourth ventricle
then either
* down through foramen of magendie into the *spinal cord *
* up through foramen of luschka into cerebral hemispheres
Reaborption
* via arachnoid villi into venous circulation
What is the choroid plexus?
Produces CSF
* 500 ml/day (20 ml/hr)
* 150 ml in the ventricular system at one time
What are the normal pressures within the cranium?
Normal ICP = 0-15 mmHg
High ICP = above 22 mmHg
Treatment threshold = above 22 x 5 mins
How is ICP measured?
ICP monitor …
Through ventricles
* ICP monitor ventriculostomy
* EVD = monitoring & CSF drainage
Through intraprenchymal
* codman in brain tissue
* no drainage
What are the manifestations of ^ ICP?
Early signs
* altered LOC
* headache
* nausea/vomitting
* visual disturbances
* motor disturbances
* changes in speech
Late signs
* entensive decrease in LOC
* flexion, extension, no motor response
* changes in vital signs, repsiratory pattern
* pupil changes
What is the monro-kellie hypothesis?
Describes the volume pressure relationship within the cranium
Cranium is made up of blood 10%, brain 10%, and CSF 80%
* when on increases, another must decrease
* if they do not then ICP raises
Primary compensation is shunting of CSF
Explain intracranial compliance
ICP level
* the higher the ICP the more stiff the complance
ICP response to stimulation
* rising ICP = poor compliance
ICP waveform
* if P2 is higher than P1 = poor compliance
How do CO2 levels affect ICP?
As CO2 increases, blood vessels dilate and increase ICP
* CO2 is potent vasodilator
Describe epidural hematoma
Rapidly expanding lesions
* squishes the brain tissue
* minimal symptoms before death
* requires immediate treatment
Describe sudural hematoma
Bleed between dura and arachnoid spaces; venous bleed
* common with old age, symptoms present late because of less brain matter with age
Describe subarachnoid hemorrhage (SAH)
symptoms and complications
Bleed between arachnoid and pia
* d/t TBI or ruptured aneurysm
* acute onset
* commonly at circle of willis
* high mortality rate
Symptoms
* thunderclap headache / worst of my life
* ranging GCS
* neck stiffness, nausea/vomitting, dilated pupils, seizures, motor deficits
Complications
* rebleeding ; manage BP, coiling, clipping
* acute hydrocephalus ; EVD
* Vasospasm ; nimodipine, CCB, keep high BP
* delayed cerebral ischemia
* ECG changes
* hyponatremia
Explain Intracerebral hemorrhage (ICH)
Bleeding into brain tissue/white matter
* d/t hypertension or trauma
* not much treatment
What are some consequences of increased ICP?
Cerebral herniation
* compensatory mechanisms are exhausted
* compressed brain tissue
Cerebral hypoperfusion
*
What are the cerebral herniation types?
Subfalcine (midlife shift)
* one hemisphere moves over midline, under falx
Central
* herniated down through into tentorium hiatus
Uncal
* herniation of medial temporal lobe into hiatus
Cerebellar tonsilar herniation (coning)
* herniates downward through foramen magnum
Explain the dural folds
Falx cerebri
* separates right & left hemispheres
Tentorium cerebelli
* separates cerebrum from cerebellum and brainstem
* above supratentorial
* below infratentorial
Cranial nerves III comes out of tentorium hiatus - can be compressed
What is cerebral hypoperfusion?
Low blood flow/oxygen/glucose to the brain - measured via CPP
* CPP = MAP - ICP
* treat when less than 60-70 mmHg for more than 5 mins
What is Cushings triad and what should you do?
What are the goals of care / management for a neuro patient?
ex. high ICP
Reducing brain volume
* osmotic diuretic (mannitol) - takes fluid from brain cells into intravascular space (fast, foley, filter)
* hypertonic saline 3% - draws fluid out of edematous brain, does not effect BP
* corticosteroids
Other Goals
* ABCs
* maintain appropriate MAP
* maintain electrolyte and fluid balance
* control fever
* nutrition
* seizure prevention
* DVT prophylaxis
