NR 340 Exam 3 Studyguide, Chapter 13 to 20, (Latest 2021) 100% Correct Study Guide

NR340 Exam 3 Chapters: 13, 14, 17, 8, 20 Page 1 of 43




NR 340 Exam 3

Nervous System Alterations
 Anatomy and Physiology
o Cells of the nervous system
 Neurons
 Basic functional unit
 Neuroglia
 Supportive structures
o Transmission of impulses
 Dendrites
 Axon
 Synaptic knob
 Releases neurotransmitters
 Bind to receptors on nerve or muscle cell to continue trasmission
o Cerebral circulation
 Receives 15% to 20% of cardiac output
 Circle of Willis joins anterior and posterior circulation
 Assures blood is evenly distributed through brain
 Carotid arteries (anterior circulation)
 Vertebral arteries (posterior circulation)
 Cerebral veins empty into venous sinuses to jugular then into Superior venacava to right atrium
 LOC good indicator of adequate blood flow
o Brain metabolism
 Neurons cannot store glucose/ O2 – needs constant supply
 Cerebral glucose < 70 mg/dL = confusion
 Cerebral glucose < 20 mg/dL = damage
 Varies from person to person
o Cerebral blood flow
 Auto regulation
 Ability for cerebral blood vessels to change in diameter to control blood volume
 Changes in pressure
 Changes in CO2
 CO2 most potent agent
 CO2↑45 (hypoventilate) causes vessels to dilate -- ↑ICP
 CO2↓35 (hyperventilate) causes vessels to constrict
o Blood-brain barrier
 Protects the brain by being selectively permeable to substances
 Does not allow things to pass into brain and CSF
o Brain

,NR340 Exam 3 Chapters: 13, 14, 17, 8, 20 Page 2 of 43
 Cerebrum
 Right and Left Hemisphere
 5 Lobes
 Frontal: Conscious thoughts, abstract thinking, judgement, voluntary movement, affect, memory,
concentration
 Parietal: Processing, association and interpretation of sensory information
 Temporal: Processing, association and interppration of autidtory information, memory and social
behavior
 Occipital: Visual processing and interpretation
 Basal ganglia: Motor control of fine body movements
 Diencephalon:
 Connects brain stem and cerebrum and midbrain
 4 Regions: thalamus, hypothalamus, subthalamus and epithalamus
 Thalamus integrates all sensations except smell
 Brainstem
 Controls vital functions
 3 major divisions:
 Midbrain
 Pons
 Medulla
 Regulates basic rhythm of respiration, rate and strength of pulse, and vasomotor activity
 Reflexes: Sneezing, swallowing, coughing and vomitting
 Cerebellum
 Fine movements
 Equilibrium
 Muscle tone
 Balance and Coordination
 Limbic System
 Primitive control of emotional responses and arousal
 Reward and Fear stimuli
 Long term memory
 Attention and Cognition
 Sleep wake cycle
 Decreased arousal – coma
o Cranial Nerves
Assessing Cranial Nerves in Critically Ill
 I –Olfactory: Smell
-Pupils react to light? (2 & 3)
 II – Optic: Visual Acuity -Dolls Eyes (4 & 6)
 III – Oculomotor: Movement of eyes, Pupillary Constriction -Corneal Reflex (5 & 7)
and Accommodation -Cold Chloric (8)
-Suction elicits Gag Reflex (9 & 10)
 IV – Trochlear: Movement of eyes
 V – Trigeminal: Chewing, Sensation of scalp, face and teeth
 VI – Abducens: Movement of Eyes
 VII – Facial: Facial expression, Lacrimation, Salvation, Taste (anterior tongue)
 VIII – Auditory: Hearing and Equilibrium
 IX – Glossopharyngeal: Swallowing, Taste (posterior tongue)

,NR340 Exam 3 Chapters: 13, 14, 17, 8, 20 Page 3 of 43
 X – Vagus: Swallowing and Laryngeal control
 XI – Spinal Accessory: Movement of head and shoulders
 XII – Hypoglossal: Movement of tongue




o Spinal Nerves
 Sympathetic Nervous System
 Origninating in thoracic and lumbar regions
 Neurotransmitter – Norepinephrine
 Vasoconstriction in skin and viscera
 Vasodilation in muscles
 Fight/Flight
 Parasmpathetic Nervous System
 Originating in crainosacral region
 Neurotransmitter – Acetylcholine
 Returns to normal state of functioning
 Rest/Digest
 Dermatomes
 Inervation of skin from each spinal nerve
 Sensory function of skin
 7 areas arise from 7 nerves
 Intracranial Pressure (ICP)
o Normal ICP: 0 – 15 mmHg
o Composed of Blood, Brain and CSF
o Normal CPP (Cerebral Profusion Pressure): 60 – 100 mmHg
 Calculated by: MAP – ICP = CPP
 MAP: (Systolic + 2(Diastolic)) / 3
o Increased Intracranial Pressure
 Associated with many problems
 Monro-Kellie Doctrine
 Increase in any component requires reduction in one or both other components to sustain
normal ICP
 Changes in LOC is first sign of Increased ICP
 Complications:
 Herniation
 Occurs when ICP is sustained at 20 mmHg or higher for 5 minutes or longer
 Cause depends on underlying issue
 Interventions
 ↑HOB
 Promote Oxygenation
 Causes of ↑ICP
 Increased Brain Volume
 Cytotoxic: Intracellular swelling or Hypoxia/Hypoosmality
 Vasogenic: Increased capillary permeability or Tumors/Meningitis

, NR340 Exam 3 Chapters: 13, 14, 17, 8, 20 Page 4 of 43
 Increased Blood Volume
 Loss of Autoregulation
 Decreased Oxygenation, Hypercapnia (Vasodilation)
 Increased metabolic Demands
 Obstruction of venous outflow

 Increased CSF
 Hydrocephalus – Blockage of normal flow, obstruction of normal reabsorption or excess
production
 Goal: ↓ICP and Profuse Brain
 Keep ICP between 0 – 15 mmHg
 Keep CPP ≥ 70 (Normal between 60 – 100)
 Intracranial Pressure Monitoring
o Indications
 GCS score 3-8 (comatose)
 Assess consciousness and arousal
 Not always accurate GCS
 Looking for motor response
 Worse Score: 3 Best Score: 15
 Get one point for “showing up”
 Hard to assess ICP
o Purpose
 Assess response to therapy
 Augment neurological assessment
o Transducer system
 Fluid filled
 Normal saline – no preservatives
 No pressurized flush system
 Assess ICP
 Microchip
 Advanced computer technology
 Fiberoptic catheter
 Don’t want to damage neurons
 COMPLICATIONS
 Infection
 Meningitis
 Hematoma
 Bleeding
o Cerebral Oxygenation Monitoring
 Jugular Oxygen Saturation (Jugular vein SvO2)
 Monitored via a fiberoptic catheter
 More accurate than CPP
 Internal jugular vein/jugular venous bulb
 Normal value 60%-70%
 Does not insure adequate profusion to brain