Powerpt Mosby Book


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Powerpt Mosby Book

  1. 1. Nervous System<br />Anatomy and Physiology Review<br />Neurological Assessment<br />
  2. 2. Anatomy and Physiology<br />
  3. 3. Neurons <br />The basic and functional unit <br />Central Nervous System<br />The spinal cord and brain<br />Peripheral Nervous System<br />The nerves and nerve ganglia<br />Autonomic Nervous System<br />Sympathetic and parasympathetic<br />
  4. 4. Neurons<br />
  5. 5. Types<br />Sensory (Afferent) neurons: transmit impulses to spinal cord or brain<br />Motoneurons(efferent) : transmit impulses away from brain or spinal cord to muscles or glands<br />Interneurons: transmit impulses from sensory neurons to motoneurons<br />
  6. 6. Structure<br />Cell Body: contains a nucleus and other cytoplasmic matter<br />Axon: carries impulse away from cell body<br />Dendrites: carry impulses toward cell body<br />Myelin: multiple, dense layers of membrane around an axon or <br />dendrite; myelinated nerve fibers transmit nerve impulses more rapidly than nonmyelinatedfibers<br />Synapse<br />Point of contact between axon of one cell and dendrite of another<br />Neuroglia: support, defend, and nourish<br />
  7. 7. Brain<br />
  8. 8. Brain Stem<br />Medulla: conducts impulses between the cord and brain<br />Pons: conducts impulses between the cord and various parts of the brain<br />Midbrain<br />Integrates and analyzes sensory input from ears, eyes and various regions of the cerebral cortex<br />Cerebellum: exerts synergic control over skeletal muscles <br />
  9. 9. Diencephalon<br />Thalamus: crudely translates sensory impulses into sensations but does not localize them<br />Hypothalamus: makes ADH and oxytocin, which are secreted by the posterior pituitary<br />Optic chiasm: the point of crossing over (decussation) of optic nerve fibers<br />
  10. 10. Cerebral Cortex<br />Frontal lobe: influences abstract thinking, sense of humor, and uniqueness of personality<br />Parietal lobe: Interpret sensations; provide appreciation of size, shape, texture, and weight<br />Temporal lobes<br />Translate nerve impulses into sensations of sound and interpret sounds (Wernicke’s area; usually in dominant hemisphere)<br />Occipital lobe<br />Translates nerve impulse into sights and interprets sights<br />
  11. 11. Brain and Cord Fluid Spaces<br />Subarachnoid space around the brain and cord, extending into the fourth and fifth lumbar vertebrae<br />Central canal inside the cord<br />Ventricles and cerebral aqueduct inside the brain; four cavities known as first, second, third, fourth ventricles<br />Cerebrospinal fluid (CFS) formed by plasma filtering from network of capillaries (chronoid plexus) in each ventricle<br />CFS circulates throughout ventricles, brain and subarachnoid space and returns to blood via venous sinuses of brain<br /> <br />
  12. 12. Autonomic Nervous<br />System<br />
  13. 13. Two Divisions<br />Sympathetic: adrenergic fibers secrete norepinephrine; influences smooth muscle of blood vessels, hairs, and sweat glands<br />Parasympathetic: cholinergic fibers secrete acetylcholine, influences digestive tract and smooth muscle to promote digestive gland secretion, peristalsis, and defecation; influences the heart to decrease rate and strengthen contractility<br />
  14. 14. DIAGNOSTIC<br />PROCEDURES<br />
  15. 15. NEUROLOGIC ASSESSMENT<br />Definition: systematic evaluation of the cranial nerves, motor and sensory functioning, and mental status to detect neurologic abnormalities<br />
  16. 16. Cranial Nerves<br />
  17. 17. Olfactory (I)<br />ability to identify familiar odors such as mini or alcohol with eyes closed and one nostrils occluded at a time<br />
  18. 18. Optic (II) <br />visual acuity measured by use of Snellen chart or by gross estimation with reading material; gross comparison of visual fields with those of examiner; color perception<br />
  19. 19. Oculomotor (III), Trochlear (IV) and Abducens(VI)<br />ability of the pupils to react equally to light and to accommodate to varying distances<br />
  20. 20. Trigeminal (V)<br />sensation of the face evaluated by lightly stroking cotton across forehead, chin, and cheeks while the client’s eyes are closed; ability to clench the teeth (jaw closed)<br />
  21. 21. Facial (VII)<br />symmetry of the facial muscles as the client speaks or is asked to make faces<br />
  22. 22. Acoustic or Vestibulocochlear (VIII)<br />hearing acuity determined by watch tick or whispered numbers; Weber’s test may be performed by holding the stem of a vibrating tuning fork at midline of the skull (should be heard equally in both ears)<br />
  23. 23. Glossopharyngeal (IX) and Vagus (X)<br />uvula should hang in midline; swallow and gag reflexes should be intact<br />
  24. 24. Spinal accessory (XI)<br />symmetric ability to turn the head or shrug the shoulders against counterforce of the examiner’s hands<br />
  25. 25. Hypoglossal (XII)<br />ability to protrude the tongue without deviation, to left or right, and without tremors<br />
  26. 26. Motor function <br />Balance<br />Observation of gait<br />Romberg Test: positive if the client fails to maintain an upright position with feet together when the eyes are closed<br />Coordination: ability to touch the finger to the nose when arms are extended or to perform similar tasks smoothly<br />Muscle strength: evaluated by having the client move symmetrical muscle groups against opposition supplied by the examiner<br />
  27. 27. Sensory function : bilateral testing of the response to light touch with cotton, sharp versus dull stimuli, vibration of a tuning fork<br />Mental Status (cerebral functioning)<br />Level of consciousness: determined by the response to stimuli (verbal, tactile or painful)<br />Orientation to person, place, and time: determined by general conversation and direct questioning<br />&gt;Judgment, memory, and ability to perform simple calculations<br />&gt;Appropriateness of behaviour and mood<br />Reflexes<br />Deep tendon reflexes (biceps, triceps, patellar, Achilles) with a reflex hammer; classification from 0 (absent) to 4+ (hyperactive); 2+ is normal<br />Plantar: plantar flexion of the foot when the sole is stroked firmly with a hard object such as tongue blade; abnormal adult response (dorsiflexion of the foot and fanning of the toes) is described as a positive Babinski and is indicative of corticospinal tract disease<br />
  28. 28. GLASGOW COMA SCALE (GCS)<br />Definition : technique of objectifying a client’s level of responses; client’s best response in each are is given a numeric value, and the three values are totalled for a score ranging from 3 (deep coma) to 15 (normal)<br />Eye-opening ability: spontaneous (4); to speech (3); to pain (2); no response (1)<br />Motor response: obeys commands (6); localizes pain (5); withdraws (4); abnormal flexing (3); extension (2); no response (1)<br />Verbal response: oriented (5); confused (4); inappropriate words (3); incomprehensible soundes (2); no response (1)<br />
  29. 29. COMPUTERIZED TOMOGRAPHY (CT)<br />Definition<br />&gt;Cross-sectional visualization of the head or other body cavity determined by computer analysis of relative tissue density as an x-ray beam passes through<br />&gt;Provides three-dimensional information about location and extent of tumors, infracted areas, atrophy, and vascular lesions<br />&gt;May be done with intravenous injection of dye for contrast enhancement<br /> <br />
  30. 30. MAGNETIC RESONANCE IMAGING (MRI)<br />Definition<br />&gt;Uses magnetic fields and radio waves to produce cross-sectional images<br />&gt;Produces accurate images of blood vessels, bone marrow, gray and white brain matter, spinal cord, globe of the eye, heart, abdominal structures, and breast tissue, and can monitor blood velocity<br />
  31. 31. LUMBAR PUNCTURE<br />Definition: involves the introduction of a needle into the subarachnoid space below the spinal cord, usually between L3 and L4 or L4 and L5<br />Purposes<br />&gt;Withdrawal of cerebral spinal fluid for diagnostic purposes or to reduce spinal pressure (normal is 70 to 200 mm H2O)<br />&gt;Measurement of spinal pressure (Queckenstedt’s test involves compression of the jugular veins; normally pressure will rise; but it blockage exists, pressure will not change)<br />&gt;Injection of medication such as anesthetics<br />
  32. 32. POSITRON EMISSION TOMOGRAPHY (PET)<br />Definition<br />&gt;Client is given strong radioactive tracers that emit signals, computer analysis of the emitted gamma rays forms images<br />&gt;Determines blood flow, glucose metabolism, and oxygen extraction<br />&gt;Effective in diagnosis of brain attack, brain tumors, epilepsy; can evaluate progress of &gt;Alzheimer’s disease, Parkinson’s disease, bipolar disorders, and head injuries<br />
  33. 33. All rights reserved<br />©2007<br />