Neurologic System: Structure and Function

Neurologic System Definition

• Controls motor, sensor, autonomic, cognitive, and behavioral activities

Two Divisions of the Nervous System

• Central nervous system, composed of the brain and spinal cord
• Peripheral nervous system, composed of cranial nerves, spinal nerves, and the autonomic nervous system

Types of Neurons

• Sensory neurons, also known as Afferent Neurons, transmit impulses from receptors to the CNS
• Motor Neurons, also termed as Efferent Neurons, transmit impulses from the CNS to effectors (muscles, glands)
• Interneurons are found entirely within the CNS and specialize in transmitting sensory/motor impulses

Neuron Basics

• The neuron is the basic functional unit of the nervous system
• Dendrites are extensions that carry impulses toward the cell body
• Axons transmit impulses away from the cell body

Neurotransmitters

• Communicate messages from one neuron to another or to a specific target tissue
• Potentiate, terminate, or modulate a specific action; can either excite or inhibit target cell activity

Key Neurotransmitters and Their Functions

• Dopamine is excitatory and controls complex movements, motivation, cognition, and regulates emotional responses
• Norepinephrine is excitatory and causes changes in attention, learning, memory, sleep, wakefulness, and mood
• Epinephrine is excitatory and controls the fight-or-flight response
• Serotonin is inhibitory and controls fluid intake, sleep, wakefulness, temperature regulation, pain control, sexual behavior, and regulation of emotion
• Acetylcholine can be excitatory or inhibitory, controls the sleep and wakefulness cycle, and signals muscles to become alert
• Gamma-aminobutyric acid (GABA) is inhibitory and modulates other neurotransmitters
• Glutamine is excitatory; high levels can result in neurotoxicity

Central Nervous System: Occipital Lobe

• Interprets visual information and memory

Central Nervous System: Cerebellum

• Controls fine movement, balance, and position or proprioception

Central Nervous System: Medulla

• Contains cardiac, respiratory, vasomotor, and reflex centers (e.g., coughing, sneezing, swallowing, vomiting)

Central Nervous System: Pons

• Located anterior to the cerebellum and superior to the medulla
• Contains two respiratory centers (apneustic and pneumotaxic) responsible for normal breathing rhythm

Central Nervous System: Midbrain

• Regulates visual reflexes, auditory reflexes, and righting reflex

Central Nervous System: Hypothalamus

• Functions include the production of hormones, regulation of body temperature, food and fluid intake, and integration of autonomic nervous system functions

Central Nervous System: Thalamus

• Primarily concerned with sensation and can suppress minor sensations

Central Nervous System: Frontal Lobe

• Largest lobe with major functions in concentration, abstract thought, information storage, and memory
• Contains Broca's area (motor control of speech) and generates impulses for voluntary movement

Central Nervous System: Parietal Lobe

• Responsible for sensory functions like touch, taste, and temperature sensation

Central Nervous System: Temporal Lobe

• Contains sensory areas for hearing and olfaction
• Plays a role in sound memory, language understanding, and music
• Wernicke's area is located here, related to language comprehension

Peripheral Nervous System: Cranial Nerves and Functions

• I (olfactory): Sensory, sense of smell
• II (optic): Sensory, visual acuity
• III (oculomotor): Motor, eye and lid movement, pupillary constriction, lens accommodation
• IV (trochlear): Motor, eye movement
• V (trigeminal): Mixed, facial sensation, corneal reflex, mastication
• VI (abducens): Motor, eye movement
• VII (facial): Mixed, facial expression, muscle movement, salivation, tearing, taste, sensation in the ear
• VIII (vestibulocochlear): Sensory, hearing and balance/equilibrium
• IX (glossopharyngeal): Mixed, taste, sensation in pharynx and tongue, pharyngeal muscles
• X (vagus): Mixed, muscles of pharynx, larynx, and soft palate; sensation in external ear, pharynx, larynx, thoracic and abdominal viscera; parasympathetic innervation of thoracic and abdominal organs
• XI (spinal accessory): Motor, sternocleidomastoid and trapezius muscles
• XII (hypoglossal): Motor, tongue movement

Spinal Nerves

• Composed of 31 pairs: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal

Autonomic Nervous System

• Regulates organ activities and is responsible for maintaining and restoring internal homeostasis

Sympathetic Nervous System

• Neurological ganglia, nerves, and plexuses innervate involuntary motor/sensory receptions
• Facilitates fight-or-flight response

Parasympathetic Nervous System

• Dominates during relaxed, non-stressful situations

Autonomic Nervous System Effects: Pupils

• Parasympathetic: Constricted pupils in the eye's circulatory system
• Sympathetic: Dilated pupils

Autonomic Nervous System Effects: Heart Rate & Blood Vessels

• Parasympathetic: Decreased heart rate and constricted blood vessels (in skeletal mm constricted)
• Sympathetic: Increased heart rate, dilated blood vessels within the heart, constricted vessels abdomen

Autonomic Nervous System Effects: Airway and Breathing

• Parasympathetic: Bronchioles constricted and decreased rate of breathing
• Sympathetic: Bronchioles dilated and increased rate of breathing

Autonomic Nervous System Effects: Digestion

• Parasympathetic: Increased peristalsis within the digestive system increasing salivary glands, stomach, liver and pancreas
• Sympathetic: Decreases peristalsis, increasing conversion of nutrients

Autonomic Nervous System Effects: Genitourinary

• Parasympathetic: Walls of the urinary bladder as well a relaxed Sphincters
• Sympathetic: Relaxes bladder walls and varies sphincter

Autonomic Nervous System Effects: Glandular

• Parasympathetic: N/A
• Sympathetic: Increases sweat

Assessment of Neurological System: Physical Exam

• Categories: Cerebral function, cranial nerves, motor function, and sensory function

Assessment of Neurological System: Cerebral Function

• Assess level of wakefulness/alertness. note the intensity of stimulus needed for response, apply pain, ask person place and time

Assessment of Neurological System: Glasgow Coma Scale (GCS)

• Easy method to determine abnormality, test three areas including eye opening, verbal response and motor response

Assessment of Neurological System: GCS Eye Opening

• Spontaneous (4), To sound (3), To pressure (2), No response (1), Non testable (NT)

Assessment of Neurological System: GCS Verbal Response

• Oriented (5), Confused (4), Words (3), Sounds (2), No response (1), Non testable (NT)

Assessment of Neurological System: GCS Motor Response

• Obeys commands (6), Localized pain (5), Withdrawal from pain (4), Abnormal flexion (3), Abnormal extension (2), No response (1), Non testable (NT)
• High score=15 patient oriented
• Comatose patient >7
• Deep coma equals 3

Cerebrovascular Accident: Risk factors

• Hypertension, Atrial fibrillation DM
• Age (>55y/o), Race (African-American)
• Smoking
• Asymptomatic Carotid Stenosis
• Obesity
• Excessive alcohol consumption

Cerebrovascular Accident: Subarachnoid Hemorrhage

• Most common cause is a leaking aneurysm

Cerebrovascular Accident: Cognitive Disturbance

• Confusion/altered LOC

Cerebrovascular Accident: Visual-Perceptual Disturbance

• Homonymous Hemianopia
• Loss of Peripheral Vision
• Double Vision

Cerebrovascular Accident: Motor Loss

• Hemiplegia, Hemiparesis, Ataxia loss/decreased tendon reflexes

Cerebrovascular Accident: Communication Loss

• Dysarthria (difficulty in speaking),
• Dysphasia (impaired speech)
• Apraxia (inability to perform a previously learned action

Cerebrovascular Accident: Expressive Aphasia

• Unable to form words that are understandable, may be able to respond in 1 word

Cerebrovascular Accident: Receptive Aphasia

• Unable to comprehend spoken word, can speak but may not make sense

Cerebrovascular Accident: Global (mixed) Aphasia

• Combination of both receptive and expressive of expressive aphasia

Cerebrovascular Accident: Sensory Loss

• Paresthesia

Cerebrovascular Accident: Emotion Deficits

• Loss of self-control
• Emotional lability
• Depression
• Withdrawal
• Fear/hostility/anger
• Feelings of isolation

Cerebrovascular Accident: Left Hemispheric Stroke

• Paralysis on right side body
• Right visual field deficit
• Aphasia (Expressive, Receptive or Global)

Cerebrovascular Accident: Right Hemispheric Stroke

• Paralysis of left side body
• Left visual field deficit
• Spatial perceptual deficits
• Increased distractibility

Cerebrovascular Accident: NURSING MANAGEMENT Prevent Shoulder Adduction

• Ensure patent airway
• Give 100% O2 - Decrease CP
• Low Fowlers neck aligned, Monitor vs GC's and pupil size
• Place belongings on unaffected side

Cerebrovascular Accident: MANAGEMENT Dysphagia

• Check the gag/cough swallow reflex before client begins to eat.
• Calm, unhurried approach
• Upright position - 90 degrees
• Place food in unaffected side mouth

Meningitis

• Inflammation of the lining around the brain and spinal cord

Meningitis: Causes

• Bacteria
• Viruses
• Microorganisms

Meningitis: Clinical Manifestations

• Symptoms are headache and fevers
• Positive Kernig's sign

Meningitis: Diagnostic Test

• bacterial culture and gram staining of CSF Blood through lumbar puncture

Meningitis: Medical management

• Vancomycin Cephalosporins
• fluid volume expanders, administer large dose of antibiotics IV- enforce respiratory Isolation/ Enforce bed rest

Encephalitis

• Acute inflammatory process of brain tissue etiologic agents

Encephalitis: Causes

• Herpes simplex virus
• Fungi
• Arthropod-borne virus

Encephalitis: Clinical Manifestations

• Symptoms include headaches, fever, nuchal rigidity
• Confusion, seizures, sensitivity to light , ataxia abnormal sleep patterns

Encephalitis: Nursing management

• Monitor vital signs, neurological assessments, comfort reduce stress
• injury prevention is important

Seizures

• Sudden abnormal excessive, electrical discharges from the brain, can change autonomic functions, consciousness or sensitization

Seizures: Simple Partial

• Does not lose consciousness
• symptoms are confined to 1 hemisphere

Seizures: Complex Partial

• Psychomotor syndrome
• Lose consciousness

Seizures: Etiologic factors-

• Traumatic brain injury
• Vascular Disease
• chemical poison or drug alcohol withdrawal

Myasthenia Gravis

• Defect in transmission of nerve impulse with increased destruction of acetylcholine

Myasthenia Gravis: Causes

• Autoimmune
• Unknown

Myasthenia Gravis: Clinical manifestations

• Dysthria General weakness or respiratory paralysis

Myasthenia Gravis: Diagnostic test

• Fast acting acetylchonlinesterase inhibitor, ptosis five minutes

Cholinergic Crisis

• Caused by overmedication Weakness

Multiple Sclerosis

• Demyelination of fiber and has exacerbations
• Charcot's triad includes scanning speech
• Intentional Tremors Nystagmus

Multiple Sclerosis: Causes

• post viral infection
• unknown

Multiple Sclerosis: Diagnostic test

MRI, EEG

Multiple Sclerosis: Managing Symptoms

• Use warm packs
• Stationary bicycling for spasticity
• eye patch

Guillain barre syndrome description

• auto immune attack of peripheral nerve

Guillain Barre: Causes

• Post Viral Infection
• Unkown
• Auto Immune

Guillain Barre: Sign and Symptoms

• Paralysis of diaphragm
• Respiratory Depression
• Dysphagia

Guillain Barre Diagnostic:

• EMG, CSF, ECG

Parkinson's disease:

• slowly progressive neurologic movement
• Excessive and un controlled sweating, rigidity leading to disability

Parkinson's disease: cause

• Idiopathic degenerated viral infection or head Trauma

Pathophysiology

• Tremor rigidity bradykinesia

Treatment interventions

• Drug interventions or surgical treatments (brain implants)

Parkinson's Disease drug complications

• Mental confusion -renal failure

Amylotrophic Lateral Sclerosis ALS

• progressive with a degenerative condition that affects motor control

ALS: symptoms

• Fatigue
• Dysphagia, and overall difficulty

ALS: medical management

• anti-spasticity meds mechanical ventilation to maximize functional communication

ALS: diagnostic testing

• emg, muscle biopsy, EEG

Spinal cord Injury description

• Loss of sensory loss
• decrease/ loss of sensory motor function in lower injury

Spinal cord Injuries: cause

• motor vehicle and falls
• Gun Shot
• sports injuries

Spinal Cord Injury: Symptoms

• bowel, bladder, sexual dysfunctions
• respiratory depression

Spinal Cord Injury: complications

• spinal, neurogenic shock
• autonomic dysreflexia
• dvt

Autonomic dysreflexia description

• life threatening

Autonomic Dysreflexia: causes

• bladder distention and bowel

Autonomic Dysreflexia: manifestations

• Pounding headache and profuse sweating

Alzheimer's Disease

• Progressive is reversible degenerative

Alzheimer's Disease: cause

• decrease in acetylcholine

Stages And Signs

cognitive deficits ,personality changes and memory loss in daily environment

Alzheimer's Disease: Diagnostics tests and Interventions

• enhance neurotransmission of Acetylcholine.

BELL' S PALSY signs & description

• Unilateral inflamtion of the seventh cranial nerve resulting in
• paralysis in one side of face.
• Adults is <45 May be linked to Herpes Zoster

BELL' S PALSY Signs and Management

• May cause Ear Pain
• Diagnosed with history and physical exam.
• Administer artificial tears
• Pt should chew food on unaffected side face.

BELL' S PALSY Treatment and Management

Treatment includes:

• Steroids Analgesics
• Antivirals Pt is to protect eyes with the administer meds as ordered.

Huntington diagnosis

• Genetic autosomal

Huntington sign and symptom

• Chorea or changes in personality

Huntington management

• Fowler needs care, counseling
• and providing a safety environment

Trigeminal Neuralgia/tic Douloureux

• is a condition of 5 cranial n involved in face
• 400xs more common with MS
• More of MS cases are men vs women

Trigeminal Neuralgia/tic Douloureux- Signs

• Sudden pain (jabbing and burning)
• Unilateral

Trigeminal Neuralgia/tic Douloureux- Intervention + Management

• Identify the signs that make it occur

Trigeminal Neuralgia/tic Douloureux- Diagnostic

• Anti seizure -history and symptoms