Chapter 36: Introduction to the Nervous System PDF

Timby’s Introductory Medical– Surgical Nursing, 13e Chapter 36: Introduction to the Nervous System Copyright © 2018 Wolters Kluwer Health | Lippincott Williams & Wilkins Nervous System Anatomy and P...

Timby’s Introductory Medical– Surgical Nursing, 13e Chapter 36: Introduction to the Nervous System Copyright © 2018 Wolters Kluwer Health | Lippincott Williams & Wilkins Nervous System Anatomy and Physiology o Categories Central nervous system (CNS) Peripheral nervous system (PNS) o Motor neurons—dendrites and axons Impulses—travel along neurons by means of synapses Neurotransmitters—excite or inhibit neurons Myelin—fatty substance covering axons Copyright © 2022 Wolters Kluwer · All Rights Reserved Central Nervous System #1 Brain Parts o Cerebrum—cortex; responsible for movement; motor and sensory neurons Loading… Pyramidal and extrapyramidal motor pathways o Cerebellum—controls and coordinates muscle movements o Brain stem—respirations, heartbeat, vasomotor activity Midbrain, pons, medulla oblongata Copyright © 2022 Wolters Kluwer · All Rights Reserved Central Nervous System #2 Cerebrum consists of two hemispheres; each hemisphere has four lobes: o Frontal o Parietal o Temporal o Occipital Corpus callosum Copyright © 2022 Wolters Kluwer · All Rights Reserved Central Nervous System #3 Skull: rigid bones Meninges o Membranes Dura mater Arachnoid Loading… Pia mater Subarachnoid space Copyright © 2022 Wolters Kluwer · All Rights Reserved Central Nervous System #4 Ventricles o Manufacture and absorb cerebrospinal fluid (CSF) o Functions of CSF Protects structures Maintains constant intracranial pressure Copyright © 2022 Wolters Kluwer · All Rights Reserved Question #1 Which part of the brain controls breathing? A) Medulla B) Cerebellum C) Cerebrum D) Thalamus Copyright © 2022 Wolters Kluwer · All Rights Reserved Answer to Question #1 A) Medulla Rationale: Medulla oblongata transmits motor impulse from the brain to the spinal cord and sensory impulses from the peripheral sensory neurons to the brain. The medulla contains vital centers concerned with respiration, heartbeat, and vasomotor activity. Copyright © 2022 Wolters Kluwer · All Rights Reserved Central Nervous System #5 Spinal Cord o Meninges o Vertebrae (vertebral column) o Functions Provides centers for reflex action Pathway for impulses to and from the brain Copyright © 2022 Wolters Kluwer · All Rights Reserved Peripheral Nervous System Structures: cranial nerves, spinal nerves, sympathetic and parasympathetic nerves o Cranial nerves—12 pairs Types: I to XII o Spinal nerves—31 pairs Doral (sensory) and ventral (motor) roots Dermatomes—spinal nerve root innervates a specific area Copyright © 2022 Wolters Kluwer · All Rights Reserved Autonomic Nervous System Function: stimulating or inhibiting smooth muscle Types o Sympathetic nervous system: released during stressful situations, emotions, severe illness Loading… Catecholamines: epinephrine, norepinephrine, dopamine o Parasympathetic nervous system: slowing heart rate, digesting food, eliminating body wastes Acetylcholine: acetylcholinesterase See Table 36-1 Copyright © 2022 Wolters Kluwer · All Rights Reserved Question #2 Which of the following responses indicates sympathetic nervous system activation? A) Tachycardia, dilated pupils B) Increased peristalsis, abdominal cramping C) Hypoglycemia, headache D) Pupil constriction, bronchoconstriction Copyright © 2022 Wolters Kluwer · All Rights Reserved Answer to Question #2 A) Tachycardia, dilated pupils Rationale: The autonomic nervous system regulates the expenditure of energy and secretes epinephrine and norepinephrine. Copyright © 2022 Wolters Kluwer · All Rights Reserved Nervous System #1 Assessment o History—trauma, drug history, family medical history o Speech patterns o Mental status o Intellectual functioning: reasoning ability o Extremity strength and movement Copyright © 2022 Wolters Kluwer · All Rights Reserved Nervous System #2 Physical Examination o Mini-Mental Status Examination o Evaluate body posture o Cranial nerves—assessment techniques o Motor function—large muscle atrophy; equality of size and strength Gait—movement and balance; Romberg test Copyright © 2022 Wolters Kluwer · All Rights Reserved Nervous System #3 Impaired Cerebral Function Decorticate posturing: arms flexed, fists clenched, legs extended Decerebrate posturing: stiff and rigid extremities Flaccidity: no motor response Copyright © 2022 Wolters Kluwer · All Rights Reserved Nervous System #4 Sensory Function o Sensitivity to heat, cold, touch, and pain Level of Consciousness o Classifications: conscious, somnolent, stuporous, semicomatose, comatose Glasgow Coma Scale See Box 36-1 and Evidence-Based Practice 36-1 o Parts—eye opening, verbal response, motor response Rancho Los Amigos Scale See Box 36-2 Copyright © 2022 Wolters Kluwer · All Rights Reserved Nervous System #5 Pupil Assessment o Size o Equality—unequal, dilated, or pinpoint o Reaction to light of pupils—failure to respond o See Box 36-2 Neck—stiffness or abnormal position, rigidity Vital signs—sudden increase or decrease—CNS disorders Copyright © 2022 Wolters Kluwer · All Rights Reserved Nervous System #6 Diagnostic Tests o Computed tomography (CT): radiopaque dyes allergy o Magnetic resonance imaging o Position emission tomography (PET)—metabolic activity of body structures o Single-photon emission computed tomography (SPECT) Brain’s cerebral blood flow, status of receptors Alzheimer and Parkinson diseases Copyright © 2022 Wolters Kluwer · All Rights Reserved Nervous System #7 Lumbar puncture (spinal tap) o Presence of pathogenic microorganism o Normal: clear and colorless, pressure of 80 to 180 mm H2O Copyright © 2022 Wolters Kluwer · All Rights Reserved Nervous System #8 Contrast studies o Cerebral angiography: detects distortion of cerebral arteries and veins; aneurysms Myelogram: to demonstrate abnormalities of the spinal canal Electroencephalogram (EEG): electrical impulses generated in the brain Nerve conduction studies: nerve injury and compression o Carpal tunnel syndrome, peripheral neuropathy Echoencephalography Copyright © 2022 Wolters Kluwer · All Rights Reserved Question #3 The nurse is assisting the client to prepare for a lumbar puncture. Which of the following actions should the nurse take first? A) Administer enemas until clear. B) Remove all metal jewelry. C) Position the client on his or her side. D) Remove the client’s denture. Copyright © 2022 Wolters Kluwer · All Rights Reserved Answer to Question #3 C) Position the client on his or her side. Answer: The client is positioned on his or her side to expose the spinal column for puncture. Copyright © 2022 Wolters Kluwer · All Rights Reserved Nursing Care Plan: Neurologic Testing Nursing Diagnosis: Knowledge deficit related to unfamiliarity with diagnostic testing process o Describe the procedure and preparation for diagnostic test. o Inform client of discomfort from procedure. Diagnosis: meningeal irritation or CNS changes o Observe for neurologic abnormalities or diminished LOC. o Report headache or sudden pain. o Position client flat for 3 hours after lumbar puncture. Copyright © 2022 Wolters Kluwer · All Rights Reserved