Chapter 10 Nervous System Copyright © 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved.

1 The Nervous System Central Nervous System Brain Spinal Cord Peripheral Nervous System Cranial Nerves Spinal Nerves Autonomic Nervous System Sympathetic Nerves Parasympathetic Nerves

2 Introduction Nervous system:  Complex: 10 billion nerve cells  Voluntary and involuntary functions  Nerves carry electrical messages  External and internal receptors

3 Introduction (cont’d.) Nerve cells:  Microscopic  Collected into macroscopic nerves  Carry electrical messages all over the body

4 Nervous System Two major divisions:  Central nervous system Brain Brain Spinal cord Spinal cord  Peripheral nervous system cranial nerves cranial nerves spinal nerves spinal nerves

5 General Structure of the Nervous System (cont’d.)  Cranial and spinal nerves Sensory nerves carry messages toward the brain. Sensory nerves carry messages toward the brain. Motor nerves carry messages from the brain. Motor nerves carry messages from the brain. Mixed nerves carry both sensory and motor fibers. Mixed nerves carry both sensory and motor fibers.  Sensory receptors

6 General Structure of the Nervous System (cont’d.) Autonomic nervous system:  Carries impulses from the central nervous system to organs.  The autonomic nervous system contains a large group of nerves that function automatically.  It controls heart, blood vessels, glands, and involuntary muscles like intestines, and hollow organs such as stomach and urinary bladder.

7 Automomic Nervous System  Sympathetic nerves stimulate body under stress.  Parasympathetic nerves balance sympathetic system. Slow heart rate Slow heart rate Lower blood pressure Lower blood pressure

8 Divisions of the Central and Peripheral Nervous System – page 346

9 Neurons, Nerves, and Glia Neuron = individual nerve cell  Dendrite – branching fibers of neuron  Cell nucleus

Neurons, Nerves, and Glia  Axon – carry impulses away Myelin sheath – fatty tissue that covers the axon giving it a white color (white matter) Myelin sheath – fatty tissue that covers the axon giving it a white color (white matter) Gray Matter – cell bodies of neurons not covered with a myelin sheath. Gray Matter – cell bodies of neurons not covered with a myelin sheath. 10

11 Neurons, Nerves, and Glia  Synapse – space where nervous impulse jumps from one neuron to another  Terminal end fibers - (secrete neurotransmitters)  Neurotransmitters - transfer impulse across synapse  Ganglia - small clusters of nerve cell bodies outside the brain and spinal cord.

12 Neurotransmitters – chemicals that control the transfer of an impulse across the synapse  Acetylcholine  Norepinephrine  Epinephrine  Dopamine  Serotonin  Endorphins

13 Image shows the parts of a neuron. Review the path of a nervous impulse.

14 Neurons, Nerves, and Glia (cont’d.) Glia cells:  Maintain health of nervous system  Do not transmit impulses

15 Four Types of Glial Cells – p. 348  Astrocytes (astroglial cells) – transport H20 and salts  Microglia (microglial cells) – protect neurons in response to inflammation  Oligodendroglia (oligodendroglial cells) – form myelin sheath.  Ependymal –line membranes in the brain and spinal cord.

Glial cells 16

17 The Brain p. 348– Controls body activities, weighs about 3 lbs

18 The Cerebrum Largest section of brain Largest section of brain Surface has nerve cells called cerebral cortex. Surface has nerve cells called cerebral cortex. Manages speech, vision, smell, movement, hearing, and thought Manages speech, vision, smell, movement, hearing, and thought

19 Cerebrum – page 350  Spaces in the middle of the cerebrum are called ventricles.  Ventricles contain cerebrospinal fluid (CSF). This fluid cushions the brain.  CSF can be removed for testing or relief of pressure on the brain.

20 The Brain

21 The Brain  Cerebellum Coordinates voluntary movements Coordinates voluntary movements Maintains balance Maintains balance

22 The Brain  Thalamus Integrates and monitors impulses from skin (pain) Integrates and monitors impulses from skin (pain)

23  Hypothalamus Controls body temperature, sleep, appetite, sexual desire, and emotions Controls body temperature, sleep, appetite, sexual desire, and emotions Regulates release of hormones from pituitary gland Regulates release of hormones from pituitary gland Monitors sympathetic and parasympathetic nervous systems Monitors sympathetic and parasympathetic nervous systems

24 The Brain The Brainstem  Pons Bridges cerebrum and cerebellum with rest of the brain Bridges cerebrum and cerebellum with rest of the brain Houses nerves for face and eyes Houses nerves for face and eyes

25 The Brainstem (cont’d.)  Medulla oblongata Connects spinal cord to brain Connects spinal cord to brain Nerve tracts from side to side Nerve tracts from side to side Regulates: Regulates: Blood vesselsBlood vessels HeartHeart Respiratory systemRespiratory system

26 Pons and Medulla

27 Thyroid Gland

28 The Spinal Cord and Meninges page 351 Spinal cord

29 Meninges Meninges

30 VOCABULARY-page 353  Acetylcholine – neurotransmitter released at nerve cells  afferent nerves – Carry messages toward brain and spinal cord  Arachnoid membrane – Middle meninges layer

VOCABULARY-page Astrocyte – type of nerve cell that transports water and salts from capillaries autonomic nervous system – controls involuntary body functions

32  Axon – microscopic fiber that carries the nervous impulse along a nerve cell.  blood-brain barrier – capillaires that selectively let certain substances enter brain tissue and keep others out. VOCABULARY- pg 353

33 cauda equina – collection of spinal nerves below the end of the spinal cord. cell body – part of nerve cell that contains the nucleus Brainstem – lower portion brain containing pons and medulla.

VOCABULARY- pg  central nervous system – brain and spinal cord  Cerebellum – posterior part of brain that coordinates muscle movements and maintains balance.  cerebral cortex – outer region of brain;containing sheets of nerve cells; gray matter of the brain

VOCABULARY- pg 353  cerebrospinal fluid (CSF) – Fluid that circulates throughout brain and spinal cord  Cerebrum – largest part of brain responsible for voluntary muscle activity, vision, speech, taste, hearing, thought, and memory. 35

36  Dendrite – microscopic branching fiber of a nerve cell that is the first part to receive the nervous impulse  dura mater – thick, outermost layer of the meninges surround and protecting the brain and spinal cord  efferent nerves – carry messages away from brain and spinal cord. VOCABULARY- pg

37 VOCABULARY – page 354  Hypothalamus –  medulla oblongata –  Meninges – 3 protective layers that surround brain and spinal cord

VOCABULARY – page 354  motor nerves – carry messages away from brain and spinal cord to muscles and organs. (efferent)  myelin sheath – White fatty tissue that surrounds, and insulates the axon of the nerve cell. Myelin speeds conduction along axons 38

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40  Neuron – nerve cells that carries impulses throughout the body  Neurotransmitter – chemical messenger released at the end of a nerve cell that stimulates or inhibits another nerve, muscle, or gland cell. VOCABULARY- page 354

41 VOCABULARY- page 354 parasympathetic nerves – Involuntary, autonomic nerves that regulate normal body functions such as HR, breathings and muscles of GI tract peripheral nervous system – Cranial, spinal, and autonomic nerves, nerves outside the brain and spinal cord.

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43 VOCABULARY – pg 355  pia mater – Thin, delicate inner membrane of meninges  Plexus – interlacing network of nerves  Receptor – organ that receives a nervous stimulation and passes it on to nerves within the body.

VOCABULARY – pg 355  sciatic nerve – nerve extending from the base of the spine down the thigh, lower leg, and foot.  Spinal nerves – 31 pairs of nerves arising from the spinal cord. 44

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47 VOCABULARY- pg 355  sympathetic nerves – Autonomic nerves that influence bodily functions involuntarily in times of stress  Vagus nerve – 10 th crainial nerve. Leaves the lead and wanders into abdominal and thoracic cavitites.  ventricles of the brain – Canals in the brain that contain cerebrospinal fluid

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49 QUICK QUIZ: QUICK QUIZ: 1. A sheet of nerve cells that produces a rounded fold on the surface of the cerebellum A. microglial B. gyrus C. parenchyma D. stroma

50 2. The thin, delicate inner membrane of the meninges A. pia mater B. dura mater C. parenchyma D. stroma QUICK QUIZ: QUICK QUIZ:

51 COMBINING FORMS page 356  cerebell/ocerebellum   cerebr/ocerebrum  dur/odura mater Subdural hematoma Subdural hematoma Combining FormMeaning

52 Nervous System  encephal/obrain Encephalitis Encephalitis Encephalopathy Encephalopathy Anencephaly Anencephaly  gli/oglial cells Glioblatoma – highly malignant tumor Glioblatoma – highly malignant tumor

53 Nervous System

54  lept/othin, slender  mening/omembranes, meninges  my/o muscle  myel/o spinal cord Combining FormMeaning Combining Forms p. 357

Combining Forms  neur/o nerve  pont/opons  radicul/o nerve root 55

56  thalam/othalamus  thec/osheath (refers to meninges)  vag/ovagus nerve Combining FormMeaning COMBINING FORMS p

57  alges/o, algesia  algia  caus/o Sensitivity to pain PainBurning Combining Form Meaning page

Combining Forms  comat/o  esthesi/o,  esthesi/a  kines/o, -kinesia Deep sleep Feeling, nervous sensation movement 58

59  -kinesis, kinetic  -lepsy  lex/o  (bradykinesia)(epilepsy)(dyslexia) Combining Form Meaning – word use COMBINING FORMS page

Combining Forms Combining Form  -paresis  -phasia Meaning – word use (hemiparesis)(aphasia) 60

61  -plegia  -praxia  -sthenia ParalysisActionStrength Combining Form Meaning page

Combining Forms Combining Form  syncop/o  tax/o Meaning – word use cut off order, coordination 62

63 QUICK QUIZ: QUICK QUIZ: 3. Which term means nerve pain? A. cephalgia B. analgesia C. hypalgesia D. neuralgia

64 QUICK QUIZ: QUICK QUIZ: 4. Which type of hematoma occurs between the skull and the dura as a result of a ruptured meningeal artery, usually after a fracture of the skull? A. subdural B. epidural C. intracerebral

65 Pathologic Conditions – p 361  Hydrocephalus  Spina bifida Spina bifida cystica Spina bifida cystica Spina bifida occulta Spina bifida occulta

66 Meningomyelocele

Degenerative, Movement, and Seizure Disorders p  Alzheimer disease (AD)  Amyotrophic lateral sclerosis (ALS)  Epilepsy  Huntington disease  Multiple sclerosis (MS)  Myasthenia gravis (MG)  Palsy  Parkinson disease  Tourette syndrome 67

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69 Bell Palsy

70 Infectious Disorders – page 366  Herpes zoster (shingles)  Meningitis  Human immunodeficiency virus (HIV) encephalopathy

71 Neoplastic Disorders page 367

72 Traumatic Disorders – page 367  Cerebral concussion: Temporary brain dysfunction after injury, usually clears within 24 hours Temporary brain dysfunction after injury, usually clears within 24 hours

Cerebral Contusion Bruising of brain tissue through direct trauma to head Neurological deficits persist longer than 24 hours Neurological deficits persist longer than 24 hours 73

74 CVA cerebral vascular accident – page 368 CVA cerebral vascular accident – page 368  Thrombotic — blood clot in artery leaving to the brain  Embolic — dislodged clot that travels to cerebral arteries  Hemorrhagic — a blood vessel, such as the cerebral artery breaks, and bleeding occurs

75 Vascular Disorders

76 Clinical Procedures – page 371 X-ray Tests Cerebral angiography Cerebral angiography Computed tomography (CT) of the brain Computed tomography (CT) of the brain Myelography Myelography

Clinical Procedures – page 371 MRI - Magnetic resonance Imaging MRI - Magnetic resonance Imaging MRA - Magnetic resonance angiogram MRA - Magnetic resonance angiogram PET - Positron emission scan PET - Positron emission scan EEG - Electroencephalography EEG - Electroencephalography 77

78 Lumbar Puncture (LP)  A needle is inserted in the spinal cord for removal of CSF.

79 MRA and MRI

80 MRI

81 CT Scan

82 PET scan reveals the cellular level metabolic changes occurring in an organ or tissue.

83 PET Scan - Positron Emission Tomography  The red color shows the highest level of glucose utilization, yellow represents less utilization and blue shows the least.

84 Abbreviations page 374 Abbreviations page 374 Abbreviations  AD  AFP   ALS   AVM Alzheimer disease alpha-fetoprotein amyotrophic lateral sclerosis arteriovenous malformation

Abbreviations – page 374 CNS central nervous system CTcomputed tomography CVAcerebrovascular accident CSFcerebrospinal fluid 85

86  EEG  GABA  ICP  LP Electroencephalogram gamma-aminobutyric acid intracranial pressure lumbar puncture Abbreviations Abbreviations

Abbreviations  MAC  MG   MRA  MRI monitored anesthetic care myasthenia gravis magnetic resonance angiography magnetic resonance imaging 87

88  1/2 P  PET   Sz  TBI  Hemiparesis  positron emission tomography  Seizure  traumatic brain injury Abbreviations Abbreviations

Abbreviations  TENS  TIA  tPA  transcutaneous electrical nerve stimulation  transient ischemic attack  tissue plasminogen activator 89