Anatomy and

Physiology of the

Neurological System

Nervous system

Coordinates and controls all activities of the body

Divisions:Central nervous system: Including the brain, and the Spinal cord.Peripheral nervous system: Made up of the cranial and spinal nerves.Autonomic nervous system: Regulates action of glands and involuntary smooth muscles in the walls of tubes and hollow organs and heart

Neurotransmitters

• Communicate messages from one neuron to another or from a neuron to a specific target tissue.

• Signaling chemicals released when a nerve impulse reaches a synapse.

Central nervous system

• Brain- largest and most complex part of the nervous system. Weighs about 1400g (adult). – Cerebrum-is composed of two hemispheres

the thalamus and the hypothalamus. Higherst function of the brain starts here.

– Cerebral cortex- stores knowledge of impulses received and controls voluntary movement, thought association, discrimination and judgment

• Frontal lobe- personality, behavior and higher intellectual functions( consciousness, learning, abstract, and creative thinking, problem solving, judgment, memory, volition, and values.

• Parietal lobe- receives sensory impulses from the opposite side of the body (sight, smell, hearing, taste ) and sensory area for interpretation of pain, touch, temperature, pressure.

• Temporal lobe- contains auditory center and stores sound memories.

• Occipital lobe- the posterior lobe of the cerebral hemisphere is responsible for visual interpretation.

oBrainstem- consist of ascending pathways, reticular formation, cranial nerves and nuclei, descending autonomic and motor pathways.Midbrain- conducts impulses between

lower and upper centers. Pons- briges or connects many structures,

midbrain and medulla oblongata, cerebellum and rest of nervous system. Center of respiration, swallowing and balance.

Cerebellum- aids in coordination of voluntary muscles and balance. Maintenance of muscles tone and posture in space( equilibrium).

Medulla oblongata- joins brain and spinal cord ( opening in the base of the skull). Contains nerve fibers ( carrying messages up to and down from brain) group together forming tracts ( bundles ) to function.

Peripheral nervous system

• Cranial nerves- conducts special senses ( smell, visual, auditory). Conducts generalized sense impulses (pain, pressure, touch, vibration, deep muscle sense).

• Spinal nerves- 31 segments ( 8 cervical, 12 thoracic 5 lumbar, 5 sacral, 1 coccygeal).

Autonomic nervous system

Control of involuntary bodily functions.–Parasympathetic ( cranioscaral )-

controls normal body functioning.–Sympathetic ( thoracolumbar )-

prepares body for “fight” and “flight”.

Assessment: The Neurologic ExaminationHealth History

• An important aspect of the neurologic assessment is the history of the present illness.

• The nurse may need to rely on yes or no answers to questions.

• The health history includes details about the onset, character, severity, location, duration, and frequency of symptoms and signs.

Physical Examination

• Neurologic examinationis often limited to a simple screening.

• The examiner must be able to conduct a thorough neurologic assessment when the patient’s history or other physical findings warrant it.

• The brain and spinal cord cannot be examined as directly as other systems of the body.

• The neurologic assessment is divided into five components: cerebral function, cranial nerves, motor system, sensory system, and reflexes.

DIAGNOSTIC EXAMINATIONI. Non-invasive tests of structures

• SPINAL & SKULL X- RAY • films examined for the signs of fracture or

bony defects, calcification, erosion of the bone, including the size of sella tursica in the skull.

• Reveals spinal fractures, dislocation, compression, curvature erosion, narrowed spinal cord & degenerative processes

• Reveals configuration, density vascular markings.

Nursing Care

- Remove hairpins, hearing aids- BRAIN SCANNING [ Radionucleide Imaging

Studies]IV injection of radioactive compound &

application of scintillation scanner in the patient’s brain an increase uptake of radioactive material at the site of pathology

Used to detect intracranial masses, vascular lesions, infarcts, hemorrhage

Nursing Care for Brain Scanning • Check for allergy to iodine• Keep NPO 4-6 hours before examination

-MAGNETIC RESONANCE IMAGING [MRI]

•visualization of the distribution of hydrogen molecules in the body in 3 dimensions

•superior imaging of body soft tissues & provides more anatomically detailed pictures than that with CT scan

•does not use harmful ionizing radiation

• Purposes:• Differentiates types of tissues in normal &

abnormal states• Clinical applications: brain, tumors/

vascular abnormalities, cardiac anomalies, blood vessels, liver dse.,renal abnormalities, gallbladder & tumor

-Nursing Care

•Remove all metallic objects andlet patient lie on platform that will be moved into a table cont’ng the magnet

• Nothing will be be felt during scanning, but (+) sound of the magnetic coils

• Closely monitor pt. w/ potential respiratory or cardiac collapse

II. Non-invasive tests of structures• OPHTHALMODYNAMOMETRY• DOPPLER ULTRASONOGRAPHY• DOPPLER SCANNING• QUANTITATIVE SPECIAL

PHONOANGIOGRAPHY

III. Invasive test of Structuresa) Lumbar Puncture introduction of hollow needle with stylet into the lumbar

subarachnoid space of the spinal between L1-L5 withdrawal of CSF fluid for diagnostic & therapeutic

purposes • Purposes:

– Measures CSF pressure [ n opening P60-150mmH2O]

– Obtain specimen fore laboratory analysis– Check color of CSF & presence of blood– Inject air, dye, drugs into spinal canal

-Nursing CarePretest

•Have client empty bladder •Position to lateral with head & neck flexed on the chest•Explain the need to remain still

Post- test•Ensure labeling of CSF specimens in proper sequence•Keep client flat for 12-24 as ordered •Force fluids

• Check puncture sites for bleeding, leakage of CSF • Assess sensation and movement in lower extremities • Monitor vital signs• Administer analgesics for headache as ordered.

b) MYELOGRAPHY injection of dye or air into lumbar or spinal

subarachnoid space followed by x-rays of the spinal column.

Used to study the spinal canal & subarachnoid space

Potential complicatins are the same as for lumbar puncture; cerebral irritation from dye

• Nursing Care:Pretest

• Keep NPO after liquid breakfast • Check for iodine allergy• Confirm signed informed consent• Pos-test• Similar with that of lumbar puncture • If oil-based dye was used [ Pantopaque], keep pt. flat

for 12 hrs.• If water-based [ Mtrizamide-Amipaque], elevate head

of bed 30-45 degree to prevent upward displacement of dye meningeal irritation & seizures

• Institute seizure precautions & don’t administer any phenothiazines

c) PNEUMOENCEPHALOGRAPHY

• introduction of air or O2 subarachnoid space by lumbar or cisternal puncture to outline the ventricular system & intracranial subarachnoid space for special x-ray studies

• to localize intracranial lesiond) VENTRICULOGRAPHY

– Introduction of air or O2 directly into lateral ventricles by ventrular puncture thru opening made in the frontal, post or occipital regions for special x-ray studies

–To visualize ventricles; localize tumors–Potential complications: HA,N,V,

meningitis, increase ICP

• Nursing Care

Post-test • Monitor VS• Check neurological status • Elevate head of bed ( 15-20degree)

e) CISTERNAL PUNCTUREo introduction of hollow needle with stylet in the

median line below the occipital bone into the cisterna magna

o remove CSF when possible to obtain at lumbar level

o potential complication: Respiratory distress

•Nursing Care

Observe for cyanosis, dyspnea & apneaSame as for lumbar puncture

f) CEREBRAL ANGIOGRAPHY injection of radiopaque substance into the

cerebral circulation [carotid/vertebral arteries on the neck] to visualize by means of x-rays the blood vessels in the head & neck

used to localize tumors, abscesses, aneurysms, hematomas & occlusions

Potential complications: anaphylactic rxns to dye, local vasospasm, adverse intracranial pressure]

• Nursing CarePretest– Keep NPO after midnight or clear liquid – Check for iodine allergy– Take baseline assessment\– Measure neck circumference– Explain warm flushed feeling and salty taste

in mouth may be felt during the procedure

During & Post-test– Have emergency equipment available– Monitor neurological status & vital signs

for shock, LOC, hemiplegia & aphasia

– Monitor swelling of the neck, difficulty of swallowing & breathing

– Administer ice collar/cap intermittently– Maintain pressure dressing– Bed rest until next morning as ordered

g) CERBRAL PERFUSION STUDIES

injection of 99 mTc to assess cerebral perfusion in suspected brain death

h) ELECTROENCEPHALOGRAM [EEG]– Consists of graphic record of the electrical activity

of brain by several small electrodes palced on the scalp

Purposes:– To detect abnormalities indicative of

intracranial pathology or pathological physiology

– To determine the existence & type of epilepsy

• Nursing CarePretest– Hair shampoo– Withhold sedatives, tranquilizers, stimulant

[ 2-3 days]

Post test– Remove electrode paste with acetone &

shampoo hair

• Peripheral Nerve Studies

ELECTROMYELOGRAPHY [EMG]

measure & records activity of contracting muscles in response to electrical stimulation

helps differentiate muscle disease from motor neuron dysfunction

•Nursing Care–Explain procedure; (+) discomfort due to needle insertion

• NERVE CONDUCTION STUDIESstimulating a

peripheral nerve at several points along its course & recording the muscle action potential or the sensory action potential

• MUSCLE BIOPSY

– Used to diagnose neuropathies & myopathies

• CELLULAR ASSESSMENTChromosome analysis assists

diagnosis of some abnormal neurologic conditions

Provides basis for genetic counseling in families w/ evidence of congenital neurologic malformations, mental retardation & seizures.

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