Cranial Nerves Nursing Lecture Slide Transcript
Slide 1: NURSING OF ADULTS 111 Introduction to Neurological Nursing
Slide 2: NERVOUS SYSTEM lCENTRAL NERVOUS SYSTEM BRAIN q SPINAL CORD q lPERIPHERAL NERVOUS SYSTEM CRANIAL NERVES---12 pairs q SPINAL NERVES---31 pairs q • 8 CERVICAL • 12 THORACIC • 5 LUMBAR • 5 SACRAL • 1 COCCYGEAL AUTONOMIC NS q • SYMPATHETIC • PARASYMPATHETIC
Slide 3: CENTRAL NERVOUS SYSTEM l 1. Spinal cord (automatic motor responses—pathways for messages to and from the brain) l 2. Lower brain (control of B.P., resp, equilibrium, muscular movements, primitive emotions) -basal ganglia, thalamus, hypothalamus, midbrain, pons, medulla & cerebellum l 3. Higher brain (cortical function – memory, reasoning, speech, vision, hearing, sensation, abstraction & patterns of responses, ) cerebral cortex
Slide 4: 2. Peripheral Nervous System = 12 Cranial & 31 Spinal Nerves 1. Central Nervous System = Brain & Spinal Cord 3. Autonomic Nervous System = Hypothalamus (part of CNS) Sympathetic Nervous System – important in emergency situations –”fight or flight” response--increase in heart rate, dilatation of bronchioles, dilatation of pupils, vasoconstriction of skin & skeletal muscles, slowing peristalsis, secretion of nor/epinephrine Parasympathetic nervous system – brings about responses assc. With restful activites--constriction of pupil, promotes digestion, slows heart rate l
Slide 5: The Brain l Centre of our thought l Interpreter of our external environment l Origin of control over conscious (voluntary) and unconscious (involuntary) movement
Slide 6: FUNCIONAL AREAS OF THE CEREBRAL CORTEX Sensory area (pain, touch, etc.) Motor cortex Visual interpretation area Written speech Parietal Lobe Frontal Lobe Occipital Lobe Motor Temporal Lobe speech Visual receiving area Brain Stem Auditory receiving area Cerebellum Auditory interpretation area
Slide 7: Functions of the cerebral cortex: l Frontal lobe – “personality” also contains the motor cortex – controls voluntary motor activity. l Prefrontal areas controls Concentration 1. Motivation 2. Ability to formulate or select goals 3. Ability to plan 4. Ability to initiate or terminate actions 5. Ability to self monitor 6. Ability to use feedback 7.
Slide 8: Cerebral Cortex (cont.) Parietal lobes – have primary receptive areas for tactile sensations i.e. temperature, touch, pressure. Also has association areas – spatial orientation and awareness of size & shape & body position (proprioception). Occipital lobe – visual receptive & association area. Visual memories are stored in this lobe – helps visually recognize & understand our environment.
Slide 9: Cerebral Cortex (cont) l Temporal lobes – auditory receptive area & secondary auditory association area. Language memories are stored on the left side. On the right side all other sound memories that are not memories q Animal sounds, train whistles, automobile horn etc. l Damage to Wernicke’s area causes the inability to understand spoken or written language or recognize music.
Slide 10: Cognitive Function Each area of the brain controls particular activities. Generally the outer and forward areas share more advanced function; the inner structures determine basic metabolic processes. Each side of the brain receives the sensory impressions and activates the muscles of the opposite side of the body.
Slide 11: WHAT PROTECTS THE BRAIN? l SKULL 8 bones encase the brain protecting it (frontal, temporal, parietal, occipital) fuse in q childhood in junctions called sutures. l MENINGES Fibrous connective tissue covering the brain the spinal cord providing protection, q support, and nourishment • Dura Mater, Arachnoid, Pia Mater l CSF Clear, colorless fluid 100-160 mls circulate b/w the subarachnoid spaces & the q ventricles. Approx. 500 mls produced per day, most is reabsorbed by the bld. Consider pressure on the brain, if not reabsorbed. Cushions and Shock Absorber q l BLOOD-BRAIN BARRIER Blocks macromolecules and many compounds from dyes and medications from q reaching the neurons. Helps keep a stable env. for neurons by regulating ion movement. q
Slide 12: l Neurons (specialized cells), make NEURONS complex connections with one another to send and receive messages in the brain and spinal cord. l The brain and spinal cord is like a computer, the neurons are like the switches and circuitry that make it work.
Slide 13: CEREBRAL CIRCULATION l Receives 15% of cardiac output l High metabolic demand and does not store nutrients – can be critical with diabetics (glucose) feel shaky, foggy, confused. l Flows against gravity (arteries fill from below and veins drain from above) l Cannot tolerate a decrease in blood flow b/c there is no collateral circulation.
Slide 14: Brainstem - The lower extension of the brain where it connects to the spinal cord. Neurological functions located in the brainstem include those necessary for survival (breathing, digestion, heart rate, blood pressure) and for arousal (being awake and alert). Most of the cranial nerves come from the brainstem. The brainstem is the pathway for all fiber tracts passing up and down from peripheral nerves and spinal cord to the highest parts of the brain.
Slide 15: Anatomy of the Autonomic Nervous System (Brunner 2000, p. 1618) What impact on body re SC injury?
Slide 16: EFFECTS ON AGING l Loss of nerve cells therefore slower to receive and send messages l Learning , memory and reasoning decline Memory loss for recent events q l Takes longer to process thoughts and put them into action No change in intelligence but it takes longer to learn q l Decreased ability to hear, see certain colors, decreased peripheral vision, sense of smell l Reduced taste buds and sense of touch in fingers and toes
Slide 17: Cognitive and Perceptual Disorders lAssessment of the Neurologic System
Slide 18: Neurologic System: History l Biographical and Demographic Data (is the data reliable) l Current Health (what brought them to seek care) l Past Health History q Childhood & Infectious Diseases – meningitis, herpes q Major Illnesses & Hospitalizations –diabetis, CVA, liver failure q Medications – prescribed, OTC, herbal q Growth and Development – duration of problem l Family Health History- ALS, MD, Huntington’s l Psychosocial History – personality changes, sleep patterns, stressors, exposure to chemicals, pesticide (Agent Orange)
Slide 19: Neurologic System: Physical Exam l Cervical spinal cord injury can exhibit dec. B/P, P & T – (loss of sympathetic nervous system) l Vital Signs – note changes l Mental Status – note changes Level of Consciousness q Orientation q Memory – long & short term q Mood and Affect- aggression & euphoria q Intellectual Performance – knowledge/calculation q Judgment and Insight – assess reasoning q Language and Communication – fluent & appropriate q
Slide 20: Neurologic System: Physical Exam l Head, Neck, and Back Inspection – q – raccoon’s eyes – basal skull fx (look for CSF from nares) – Battle’s sign – middle basal skull fx – bruising over mastoid process (look for CSF from ears) Palpation q – Nodules, boggy skull, nuchal rigidity Percussion q – Gentle percussion – watch for pain response Auscultation q – Major neck vessels – turbulent - ? High risk for CVA
Slide 21: Neurologic System: Physical Exam l Cranial Nerves Olfactory Nerve (CNI): Smell q Optic Nerve (CN II): Vision q Oculomotor (CNIII),Trochlear (CNIV), Abdocens (CNVI): Eye control q Trigeminal Nerve (CNV): Sensations of the face, movement of the mouth q Facial Nerve (CNVII): Facial muscles q Acoustic Nerve (CNVIII): Hearing q Glossopharyngeal (CNIX), Vagus (CNX) Nerves: Palate, Uvula q Spinal Accessory Nerve (CNXI): Muscles of the Shoulders and Neck q Hypoglossal Nerve (CN XII): Tongue q
Slide 22: Neurologic System: Physical Exam l Motor System Muscle Size- symmetrical q Muscle Strength - symmetrical q Muscle Tone – rigid/flaccid/normal q Muscle Coordination – repetitive movement q Gait and Station- proprioception q Movement – fine & gross motor q Motor Testing of Unconscious Patients – to test response q to pain – sternal rub, pressure on nail bed, orbit of the eye.
Slide 23: Neurologic System: Physical Exam l Sensory Function Superficial Sensations q • Touch and Pain Mechanical Sensations q • Vibration – tuning fork • Proprioception Discrimination – stereognosis – distinguish objects, q graphism – trace letters on palm of hand
Slide 24: Neurologic System: Physical Exam l Abnormal Reflexes Rooting Reflex q Babinski’s Reflex q Sucking Reflex q Jaw Reflex q Grasp Reflex q Palm-Chin Reflex q Chewing Reflex q Clonus q Snout Reflex q
Slide 25: Posturing l Abnormal flexion (decorticate) internal rotation of the arms & wrists l Abnormal extension (decerebrate) extension & external rotation of arms & wrists – more serious than abnormal flexion - midbrain
Slide 26: Neurologic System: Physical Exam l Normal Reflexes Superficial (cutaneous) Reflexes q Abdominal Reflex q Plantar Reflex q Corneal Reflex q Pharyngeal Reflex - gag q Cremasteric Reflex q Anal Reflex – check with MVA q Deep Tendon Reflexes q
Slide 27: Neurologic System: Physical Exam l Autonomic Nervous System Cannot be examined directly q Clinical Manifestations q • Increase/Decrease Heart Rate • Vasoconstriction/Dilatation Peripherally • Bronchoconstriction/Dilatation • Increase/Decrease Peristalsis • Pupil Constriction/Dilatation
Slide 28: Neurologic System: Physical Exam l Functional Assessment l Clinical Applications l Diagnostic Tests-Noninvasive Skull and Spinal X-Ray Studies q Computed Tomography q Magnetic Resonance Imaging q Positron Emission Tomography q
Slide 29: Neurologic System: Diagnostic Tests lInvasive Lumbar Puncture q Myelography q Cisternal Puncture q Cerebral Angiography q Cerebral Perfusion Studies q
Slide 30: Neurologic System:Diagnostic Tests l Noninvasive Tests of Function Electroencephalogram q Evoked Potential Studies q Neuropsychological Testing q l Invasive Tests of Function Caloric Testing q Peripheral Nerve Studies q Muscle Biopsy q Cellular Assessment q
Slide 31: CONSCIOUSNESS … is a state of general awareness of oneself and environment. Consciousness has two components: 1. Arousal (wakefulness): concerned with the person’s wakefulness (Controlled by Cerebral Cortex Function + Upper Brain Stem) 2. Content/cognition/awareness (cognitive + affective function or awareness of self): the sum of cerebral mental functions (Controlled by Cerebral Cortex Function).
Slide 32: AROUSAL The mediator of arousal and sensory stimulation is the RETICULAR ACTIVATING SYSTEM (RAS). The RAS is located in the Brain Stem and contains projections between the Thalamus and the Cortex. A network of neurons in the RAS monitors ascending and descending stimuli. Nerve cells run through the medulla, pons, midbrain, thalamus, and hypothalamus. RAS maintains muscle tone, keeps the higher brain in a state of alert wakefulness, and filters incoming messages.
Slide 33: HOW UNCONSIOUSNESS OCCURS l Disruption of the ascending reticular activating system (extending from the length of the brain stem into the thalamus) l Disruption in the function of one or both cerebral hemispheres l Metabolic depression of the brain (i.e.-----as with drug overdose)
Slide 34: DISORDERS PRODUCING UNCONSCIOUSNESS l Structural lesions in the brain placing pressure on the brain stem or other structures Brain tumors q Head trauma q Cerebral hemorrhage q l Metabolic disorders and diffuse lesions Hypoxia/Ischemia q Liver, lung and kidney disorders q Toxins, hypoglycemia, fever, infections, fluid/electrolyte q imbalance, acid-base imbalance l Psychogenic causes Catatonia and Hysteria q
Slide 35: l Why is it important to assess LOC? l How do we do this?
Slide 36: Stages of decreasing LOC l ALERT l CONFUSION l DISORIENTATION l LETHARGY l OBTUNDATION l STUPOR l COMA
Slide 37: SUSTAINED UNCONSIOUSNESS l COMA A STATE OF SUSTAINED UNCONSIOUSNESS IN q WHICH THE PATIENT DOES NOT RESPOND TO VERBAL STIMULI, MAY HAVE VARYING RESPONSES TO PAINFUL STIMULI, DOES NOT MOVE VOLUNTARILY, MAY HAVE ALTERED RESPIRATORY PATTERNS, MAY HAVE ALTERED PUPILLARY RESPONSES TO LIGHT, AND DOES NOT BLINK. (Black, 5th edition)
Slide 38: BREATHING IN THE UNCONSCIOUS CLIENT l Respiration controlled by cerebrum, pons and medulla l Airway obstruction and aspiration common complications Obstructed airways causes§CO2 retention§ q vasodilation§cerebral edema§increased ICP Reduced O2 levels§less oxygen to brain§ q increased ICP
Slide 39: UNCONSCIOUS CLIENT l CN responsible for eye movement exit thru the brain stem. If compressed eye movement is impaired. l Normally gaze straight ahead and track together l In comatose client they are uncoordinated, and pupillary response is abnormal. (Eyes movements can be dysconjugate, ocular bobbing, roving, nystagmus).
Slide 40: PUPILLARY CHANGES IN THE UNCONSCIOUS CLIENT l Nuclei of CN11 and 111 located below cerebrum and in mid-brain l Assessed for size, equality, reaction, responsive l Fixed and dilated late signs of herniation and severe hypoxia l Other causes Hypothermia, Medications, Lesions q
Slide 41: MOTOR RESPONSES SEEN IN UNCONSCIOUSNESS l POSTURING Decorticate q Decerebrate q Flaccidity (Unilateral or Bilateral) q l OTHER MOTOR SIGNS Primitive sucking or snout reflexes q Strong reflexive hand grasps q Restlessness q Resistance to passive movements q Hemiplegia q Hemiparesis q Seizures q
Slide 42: CHANGES IN VITAL SIGNS l Wide variations may be seen with various levels of consciousness and some changes directly related to the cause of the unconsciouness l Cushings (Triad) may develop with increased ICP Decreased pulse q Increased systolic BP with same or slightly higher q diastolic resulting in a widened Pulse Pressure Slow respirations q
Slide 43: ASSESSING CONSCIOUSNESS l
Slide 44: The Glasgow Coma Scale (GCS) Universally used Measures eye, verbal, and motor response Excellent scale to measure Arousal. Know the difference b/t content & arousal
Slide 45: GLASGOW COMA SCALE SCORE (GCS) Eyes 1 Closed at all times 2 Opens to pain 3 Opens to voice command 4 Open spontaneously Motor 1 No response A score of 10 or less 2 Extension (decerebrate rigidity) indicates a need for 3 Flexion posturing emergency attention 4 Flexion withdrawal 15 (top score) 5 Localizes painful stimulus 6 Obeys commands A score less than 7 is Verbal 1 No response interpreted as coma 2 Incomprehensible sounds 3 Inappropriate words 4 Disoriented and converses 5 Oriented and converses
Slide 47: CONTENT Besides orientation to time, place and person the following cognitive abilities should also be assessed: •Attention and vigilance •Memory – short, intermediate, long term •Language – understanding of spoken and written word •General fund of information •Construction ability •Sequencing activities •Problem solving •Abstraction •Insight and judgement The Mini Mental Status Exam is an example of a test for cognitive function.
Slide 48: Any process that results in ↑ will ICP produce impairment of content and arousal. ***Remember restless and other changes in behavior frequently precede changes in vital signs, However, changes in LOC will occur first.
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