W4 D3 - Neuro A&P

Question 1

What are the 3 classifications of the neurons?

Answer 1

SAME - sensory afferent motor efferent
Afferent /sensory - carries signalstowards the brain
Efferent / motor - away from the brain
Interneurons - connects neurons within the nervous system

Question 2

Differentiate spinothalamic tracts vs. corticospinal tracts

Answer 2

Spinothalamic tracts
* ascending sensory tracts

Corticospinal tracts
* descending motor tracts

Question 3

What are the functions & potential deficits associated with cranial nerves oculomotor 3, glossopharyngeal 9, vagus 10?

Answer 3

Occulomotor
* raises eyelid, eye movement, 4/6 directions
* pupil constriction

Glossopharyngeal
* gag, swallowing, pronation

Vagus
* swallowing, speech issues

Question 4

What are the main functions of the cerebral lobes?

& their possible major deficits

Answer 4

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

Question 5

What are the main functions of the cerebellum & brainstem?

& their possible major deficits

Answer 5

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

Question 6

What are the characteristics of the meninges?

Answer 6

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

Question 7

What is the purpose of the meninges?

Question 8

Outline the path of cerebrospinal fluid from production, through the ventricular system to reabsorption

Answer 8

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

Question 9

What is the choroid plexus?

Answer 9

Produces CSF
* 500 ml/day (20 ml/hr)
* 150 ml in the ventricular system at one time

Question 10

What are the normal pressures within the cranium?

Answer 10

Normal ICP = 0-15 mmHg
High ICP = above 22 mmHg
Treatment threshold = above 22 x 5 mins

Question 11

How is ICP measured?

Answer 11

ICP monitor …
Through ventricles
* ICP monitor ventriculostomy
* EVD = monitoring & CSF drainage

Through intraprenchymal
* codman in brain tissue
* no drainage

Question 12

What are the manifestations of ^ ICP?

Answer 12

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

Question 13

What is the monro-kellie hypothesis?

Answer 13

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

Question 14

Explain intracranial compliance

Answer 14

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

Question 15

How do CO2 levels affect ICP?

Answer 15

As CO2 increases, blood vessels dilate and increase ICP
* CO2 is potent vasodilator

Question 16

Describe epidural hematoma

Answer 16

Rapidly expanding lesions
* squishes the brain tissue
* minimal symptoms before death
* requires immediate treatment

Question 17

Describe sudural hematoma

Answer 17

Bleed between dura and arachnoid spaces; venous bleed
* common with old age, symptoms present late because of less brain matter with age

Question 18

Describe subarachnoid hemorrhage (SAH)

symptoms and complications

Answer 18

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

Question 19

Explain Intracerebral hemorrhage (ICH)

Answer 19

Bleeding into brain tissue/white matter
* d/t hypertension or trauma
* not much treatment

Question 20

What are some consequences of increased ICP?

Answer 20

Cerebral herniation
* compensatory mechanisms are exhausted
* compressed brain tissue

Cerebral hypoperfusion
*

Question 21

What are the cerebral herniation types?

Answer 21

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

Question 22

Explain the dural folds

Answer 22

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

Question 24

What is cerebral hypoperfusion?

Answer 24

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

Question 25

What is Cushings triad and what should you do?

Question 26

What are the goals of care / management for a neuro patient?

ex. high ICP

Answer 26

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