Chapter 10 Nervous System Copyright © 2008, 2005 by Saunders, an imprint of Elsevier Inc. All rights reserved. The Nervous System Central Nervous System Brain Spinal Cord Peripheral Nervous System Cranial Nerves Spinal Nerves Autonomic Nervous System Sympathetic Nerves Parasympathetic Nerves 1 Introduction Nervous system: Complex: 10 billion nerve cells Voluntary and involuntary functions Nerves carry electrical messages External and internal receptors 2 Introduction (cont’d.) Nerve cells: Microscopic Collected Carry into macroscopic nerves electrical messages all over the body 3 Nervous System Two major divisions: Central nervous system Brain Spinal cord Peripheral nervous system cranial nerves spinal nerves 4 General Structure of the Nervous System (cont’d.) Cranial and spinal nerves Sensory nerves carry messages toward the brain. Motor nerves carry messages from the brain. Mixed nerves carry both sensory and motor fibers. Sensory receptors 5 parasympathetic and sympathetic nerves 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 Lower blood pressure https://www.youtube.com/watch?v=H8ItFuDgYKw 8 Divisions of the Central and Peripheral Nervous System – page 346 9 Neurons, Nerves, and Glia Neuron = individual nerve cell Dendrite Cell – branching fibers of neuron nucleus 10 Neurons, Nerves, and Glia Axon – carry impulses away 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. 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 (astroglial cells) – transport H20 and salts Astrocytes (microglial cells) – protect neurons in response to inflammation Microglia (oligodendroglial cells) – form myelin sheath. Oligodendroglia –line membranes in the brain and spinal cord. Ependymal These are the supportive, protective, and connective cells of the central nervous system. 16 Glial cells 17 The Brain p. 348– Controls body activities, weighs about 3 lbs 18 The Brain The brain is divided into right and left hemispheres. The brain consists of four major lobes, including the frontal lobe, parietal lobe, temporal lobe, and occipital lobe. http://study.com/academy/lesson/parts-of- the-brain.html 19 The Cerebrum Largest section of brain Surface has nerve cells called cerebral cortex. Manages speech, vision, smell, movement, hearing, and thought 20 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. 21 The Brain 22 The Brain Cerebellum Coordinates voluntary movements Maintains balance 23 The Brain Thalamus Integrates and monitors impulses from skin (pain) 24 Hypothalamus Controls body temperature, sleep, appetite, sexual desire, and emotions Regulates release of hormones from pituitary gland Monitors sympathetic and parasympathetic 25 nervous systems The Brain The Brainstem Pons Bridges cerebrum and cerebellum with rest of the brain Houses nerves for face and eyes 26 The Brainstem (cont’d.) Medulla oblongata Connects spinal cord to brain Nerve tracts from side to side Regulates: • Blood vessels • Heart • Respiratory system 27 Pons and Medulla 28 Thyroid Gland 29 The Spinal Cord and Meninges page 351 Spinal cord 30 Spinal Cord The spinal cord is the column of nervous tissue from the medulla oblongata to second lumbar vertebra. It serves as a pathway for impulses to and from the brain. The inner section of the cross-section of the spinal cord is gray matter. The outer section of the cross-section of the spinal cord is white matter. 31 Meninges Meninges: Meninges are the three layers of connective tissue membranes that surround the brain and spinal cord. 32 Meningitis https://www.youtube.com/watch?v=FHLW nlrmKNg 33 VOCABULARY-page 353 Acetylcholine – neurotransmitter released at nerve cells afferent nerves – Carry messages toward brain and spinal cord Arachnoid membrane – Middle meninges layer 34 VOCABULARY-page 353 Astrocyte – type of nerve cell that transports water and salts from capillaries autonomic nervous system – controls involuntary body functions 35 VOCABULARY- pg 353 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. 36 VOCABULARY- pg 353 Brainstem – lower portion brain containing pons and medulla. cauda equina – collection of spinal nerves below the end of the spinal cord. cell body – part of nerve cell that contains the nucleus 37 VOCABULARY- pg 353 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 38 VOCABULARY- pg 353 fluid (CSF) – Fluid that circulates throughout brain and spinal cord cerebrospinal – largest part of brain responsible for voluntary muscle activity, vision, speech, taste, hearing, thought, and memory. Cerebrum 39 VOCABULARY- pg 353-354 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. 40 VOCABULARY – page 354 Hypothalamus medulla – oblongata – – 3 protective layers that surround brain and spinal cord Meninges 41 VOCABULARY – page 354 nerves – carry messages away from brain and spinal cord to muscles and organs. (efferent) motor sheath – White fatty tissue that surrounds, and insulates the axon of the nerve cell. Myelin speeds conduction along axons myelin 42 43 VOCABULARY- page 354 – nerve cells that carries impulses throughout the body Neuron – chemical messenger released at the end of a nerve cell that stimulates or inhibits another nerve, muscle, or gland cell. Neurotransmitter 44 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. 45 46 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. 47 48 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. 49 50 51 VOCABULARY- pg 355 nerves – Autonomic nerves that influence bodily functions involuntarily in times of stress sympathetic nerve – 10th crainial nerve. Leaves the lead and wanders into abdominal and thoracic cavitites. Vagus of the brain – Canals in the brain that contain cerebrospinal fluid ventricles 52 53 QUICK QUIZ: 1. A sheet of nerve cells that produces a rounded fold on the surface of the cerebellum A. B. C. D. microglial gyrus parenchyma stroma 54 QUICK QUIZ: 2. The thin, delicate inner membrane of the meninges A. B. C. D. pia mater dura mater parenchyma stroma 55 COMBINING FORMS page 356 Combining Form cerebell/o Meaning cerebellum cerebr/o cerebrum dur/o dura mater Subdural hematoma 56 Nervous System encephal/o Encephalitis Encephalopathy Anencephaly gli/o brain glial cells Glioblatoma – highly malignant tumor 57 Nervous System 58 Combining Forms p. 357 Combining Form Meaning lept/o thin, slender mening/o membranes, meninges my/o muscle myel/o spinal cord 59 Combining Forms neur/o nerve pont/o pons radicul/o nerve root 60 COMBINING FORMS p. 357-358 Combining Form Meaning thalam/o thalamus thec/o sheath (refers to meninges) vag/o vagus nerve 61 page 358-359 Combining Form alges/o, algesia Meaning Sensitivity to pain algia Pain caus/o Burning 62 Combining Forms Deep sleep comat/o esthesi/o, esthesi/a Feeling, nervous sensation kines/o, movement -kinesia 63 COMBINING FORMS page 359 - 360 Combining Form Meaning – word use -kinesis, (bradykinesia) kinetic -lepsy (epilepsy) lex/o (dyslexia) 64 Combining Forms Combining Form Meaning – word use -paresis (hemiparesis) -phasia (aphasia) 65 page 360-361 Combining Form Meaning -plegia Paralysis -praxia Action -sthenia Strength 66 Combining Forms Combining Form Meaning – word use syncop/o cut off tax/o order, coordination 67 QUICK QUIZ: 3. Which term means nerve pain? A. B. C. D. cephalgia analgesia hypalgesia neuralgia 68 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 69 Pathologic Conditions – p 361 Hydrocephalus Spina bifida Spina bifida cystica Spina bifida occulta 70 Meningomyelocele 71 Degenerative, Movement, and Seizure Disorders p. 363-364 Alzheimer disease (AD) Amyotrophic lateral sclerosis (ALS) Epilepsy Huntington disease Multiple sclerosis (MS) Myasthenia gravis (MG) Palsy Parkinson disease Tourette syndrome 72 73 Bell Palsy 74 Infectious Disorders – page 366 Herpes zoster (shingles) Meningitis Human immunodeficiency virus (HIV) encephalopathy 75 Neoplastic Disorders page 367 76 Traumatic Disorders – page 367 Cerebral concussion: Temporary brain dysfunction after injury, usually clears within 24 hours 77 Cerebral Contusion Bruising of brain tissue through direct trauma to head Neurological deficits persist longer than 24 hours 78 CVA cerebral vascular accident – page 368 Thrombotic — blood clot in artery leaving to the brain — dislodged clot that travels to cerebral arteries Embolic — a blood vessel, such as the cerebral artery breaks, and bleeding occurs Hemorrhagic 79 Vascular Disorders 80 Clinical Procedures – page 371 X-ray Tests Cerebral angiography Computed tomography (CT) of the brain Myelography 81 Clinical Procedures – page 371 MRI - Magnetic resonance Imaging MRA - Magnetic resonance angiogram PET - Positron emission scan EEG - Electroencephalography 82 Lumbar Puncture (LP) A needle is inserted in the spinal cord for removal of CSF. 83 MRA and MRI 84 MRI 85 CT Scan 86 PET scan reveals the cellular level metabolic changes occurring in an organ or tissue. 87 PET Scan - Positron Emission Tomography The red color shows the highest level of glucose utilization, yellow represents less utilization and blue shows the least. 88 Abbreviations page 374 Abbreviations AD Alzheimer disease AFP alpha-fetoprotein ALS amyotrophic lateral sclerosis AVM arteriovenous malformation 89 Abbreviations – page 374 CNS central nervous system CT computed tomography CVA cerebrovascular accident CSF cerebrospinal fluid 90 Abbreviations EEG Electroencephalogram GABA gamma-aminobutyric acid ICP intracranial pressure LP lumbar puncture 91 Abbreviations MAC monitored anesthetic care MG myasthenia gravis MRA MRI magnetic resonance angiography magnetic resonance imaging 92 Abbreviations 1/2 P PET Hemiparesis positron emission tomography Sz Seizure TBI traumatic brain injury 93 Abbreviations TENS TIA tPA transcutaneous electrical nerve stimulation transient ischemic attack tissue plasminogen activator 94