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Nervous System Chapter 14 Medical Terminology. Nervous System System of conducting tissues (nerves) that receive information from the environment and.

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Presentation on theme: "Nervous System Chapter 14 Medical Terminology. Nervous System System of conducting tissues (nerves) that receive information from the environment and."— Presentation transcript:

1 Nervous System Chapter 14 Medical Terminology

2 Nervous System System of conducting tissues (nerves) that receive information from the environment and control both voluntary and involuntary functions of the body and consciousness

3 Cellular Anatomy Two types of cells: –Neurons Transmit impulses (conduct) –Sensory neurons (afferent) –Motor neurons (efferent) –Mixed (both afferent and efferent) –Neuroglia Supporting cells

4 Neurons: Structure Cell body –Nucleus, cytoplasm, organelles Dendrites –Projections of the cell body –Receive and carry impulses Axons –Single, long projections from cell body –Also transmit impulses

5 Neurons: Structures Myelin sheath –Covering outer layer of axon –Lipid layer –White color –Makes up the white matter in CNS –Acts as an insulator –Speeds up impulse transmission in the axon

6 More about myelin Unmyelinated structures –Appear gray, gray matter –CNS and spinal column Peripheral nerve (PNS) –Schwann cell = myelin sheath –Neurilemma/neurolemma = this thin layer –Node of Ranvier = space between Schwann cells

7 Neurons: Other terms Synapse –Space between neurons –Between axon terminal and dendrites of adjacent neurons Axon terminal Neurotransmitter

8 Neuroglia: Four Types Astrocytes star shaped support cells for neurons form capillary sheaths (BBB) Oligodentrocytes help in CNS myelin development Microglia: phagocytes

9 Neuroglia: Four Types Ependyma –Ciliated cells –Line cavities in CNS (ventricles) –Help CSF circulation

10 Nervous System Anatomy Central Nervous System (CNS) –Brain –Spinal Cord Peripheral Nervous System (PNS) –12 pairs of cranial nerves (CN I-XII) From basilar surface of brain –31 pairs of spinal nerves From spinal cord

11 CNS Anatomy: Brain Meninges three protective membranes around CNS Cerebrum corpus callosum structures connecting hemispheres gyri (gyrus) = folds or convolutions sulci (sulcus) =fissues, furrows

12 CNS Anatomy: Brain Lobes of the brain: –Frontal –Parietal –Temporal –Occipital –Insula

13 Brain Anatomy Cerebral Cortex –Thin outer layer –Gray matter due to millions of cell bodies –Rest of cerebrum is myelinated axons (white) Cerebrum: Functions –Sensory perception, interpretation –Voluntary movement, language, memory –Emotional aspects of behavior

14 Other Structures in the Brain: Cerebellum –Posterior aspect –Coordinates and refines movement –Balance and equilibrium

15 Other Brain Structures Diencephalon (interbrain) –Thalamus Receives & transmits all sensory info except smell to the cerebrum Transmits impulses from cerebrum to efferents –Hypothalamus Coordinates autonomic impulses Temperature regulation Control of endocrine system

16 Other Brain Structures: Brainstem: control of respiration, cardiac activity Pathway between brain and spinal column –Midbrain (mesencephalon) –Medulla (oblongata) –pons

17 CNS structures: Spinal Cord Ascending tracts –Bring sensory input to CNS Descending tracts –Send impulses to muscles, end organs Cross-section: –Gray matter-inner part of cord –White matter—outer part of cord Spinal cavity –Spinal nerves exit from intervertebral spaces –Cauda equina

18 CNS: Meninges Dura –Outermost, very fibrous –Subdural space: filled with serous fluid Arachnoid –Thinner, looks like a spider web –Subarachnoid space: contains CSF Pia –Innermost layer, also thin –Contains blood vessels and lymphatics

19 Peripheral Nervous System (PNS) Cranial Nerves Spinal Nerves Somatic Nervous system (SNS) Autonomic Nervous system (ANS)

20 PNS: Cranial Nerves Exit mostly from base of the brain Named and denoted by I through XII Mostly involve facial, eye, mouth movement and sensation and the special senses of hearing, taste, sight Are afferent, efferent, and mixed nerves

21 PNS: Spinal Nerves Exit from spinal cord and go to muscles and organs Each has two attachments to spinal cord: –Anterior root: motor fibers –Posterior root: sensory fibers

22 Somatic Nervous System (SNS) Voluntary functions Mostly supplies skeletal muscles

23 Autonomic Nervous System (ANS) Supplies nerves (ennervates) involuntary functions Ennervates glands, smooth & cardiac muscles, etc Sympathetic system –Fight or flight Parasympathetic system –Functions that are the opposite, resting

24 Medical Word Elements Cerebro: cerebrum Cranio: cranium or skull Encephalo: brain Kinesio: movement Ganglio: knot or mass (a ganglion) Narco: sleep, stupor Neuro: nerve

25 Medical word elements: Radiculo: nerve root (radiculopathy) Theco: sheath (intrathecal) Tono: tension (tonometry, dystonic)

26 Medical Word Elements Others are from anatomic structure names Ventriculo: ventricles Thalamo: thalamus Myelo: spinal cord or bone marrow Meningo: meninges Glio: neuroglial tissue Dentro: treee-like

27 Suffixes: Neuro -algia or algesia: pain -asthenia or –paresis: weakness, disability -esthesia: feeling -kinesia: movement -lepsy: seizure (epilepsy, narcolepsy) -phasia: speech -plegia: paralysis

28 Suffixes: Neuro -plexy: stroke -taxia: coordination (ataxia) -trophy: development

29 Prefixes: Neuro Contra- = against/opposite Pachy- = thick Para- = near Syn- = together, joined

30 Neurological Pathology Common symptoms: –Pain (head, neck, back, periphery) –Abnormal movements –Gait abnormalities –Disturbances of special senses –Speech abnormalities –Altered level of consciousness –Focal weakness –seizures

31 Bell’s Palsy Facial paralysis (unilateral usually)) Involves CN VII Herpes viral infection Usually transient Facial weakness and numbness, problems with blink reflex and speech

32 Cerebrovascular Disease Cerebrovascular accident (CVA) or stroke –Focal loss of function due to loss of blood supply –Lasts more than 24 hours –Causes: Ischemic: due to thrombus or carotid emboli (75%) Hemorrhagic (25%) Extrinsic compression of blood vessel (rare)

33 Cerebrovascular Disease Typical CVA symptoms: Anterior stroke: –Hemiparesis or hemiplegia –Aphasia or dysphasia –Partial loss vision/ visual field Posterior stroke: –Balance problems, ataxia, vertigo

34 Cerebrovascular Disease Transient Ischemic Attack (TIA) –Focal symptoms like a CVA, lasting less than 24 hours –Typical symptoms: weakness or clumsiness of upper extremity, visual field loss, hemiparesis of the face, paresthesias of upper extremities –Indicates risk of CVA within next year

35 Seizure Disorders Nerve conduction dysrhythmias Epilepsy = chronic seizure disorder Generalized Sz (gran mal, tonic clonic) –Movements of entire body –unconsciousness Partial Sz (focal) (Jacksonian) Petit mal (absence Sz)

36 Seizure Disorders: Causes Congenital anomalies Brain injury Metabolic disease Brain tumors Genetic disorders Vascular anomalies

37 Seizures: Are often the symptom of the disease Status epilepticus –Life-threatening –Lengthy or muliple Sz Electroencephalography Magnetoencephalography Rx: antiepileptic meds

38 Parkinson Disease Parkinsonism also A movement disorder Progressive neurological disease affected the movement control centers of the brain Deficiency of dopamine, a neurotransmitter in the brain Rx: L-dopa administration

39 Parkinson Disease Symptoms: Bradykinesia or hypokinesia Uncontrollable shaking of head Shuffling gait, pill rolling of fingers Tremors Some stiffness, Mask-like facial expressions

40 Multiple Sclerosis (MS) Progressive demyelinating disease of CNS Impeding nerve conduction Disease of young adults, usually females Autoimmune disease suspected, fatal Symptoms: –Tremors, bradykinesias –Visual disturbances, muscle weakness

41 Alzheimer Disease Progressive, fatal neurological degenerative disease of the elderly Memory loss, cognitive dysfunction, anxiety, decline in social skills and ADL Plaques develop in cerebral cortex Common cause of senile dementia in US Some medications slow progress of disease

42 Mental Illnesses Alterations in behavior, mood, thought Some general terminology: –Phobia –Delusion –Hallucinations –Obsessive compulsive disorders (OCD) –Psychiatrist or clinical psychologist

43 Categories of Mental Illnesses Affective (mood) disorders –Mania –Depression –Manic-depressive disorder (bipolar disorder) Eating disorders –Anorexia nervosa –Bulimia nervosa

44 Categories of Mental Illnesses Anxiety disorders Panic attacks Attention-deficit hyperactivity disorder (ADHD) Schizophrenia (thought disorder)

45 Neuro Oncology Most intracranial neoplasms are primary brain tumors Papilledema = classic sign of intracranial tumor, slowly rising ICP Metastatic tumors to brain –Fairly common, slower growing than their primary tumors, more easily resected than primary CNS tumors

46 Neuro Infections Meningitis –Bacterial = most rapid, meningococcal –Viral or fungal Encephalitis –Usually viral Brain or Spinal Cord abscesses –Usually bacterial –Parasitic also possible

47 Intracranial Hemorrhages Epidural hemorrhage Subdural hemorrhage Subarachnoid hemorrhage Intracerebral hemorrhage

48 Epidural Hemorrhage Arterial bleeding Often involves parietal skull fracture Disrupts the middle meningeal artery Famous “lucid interval” symptoms Usual symptoms: headache, unconsciousness, unilateral weakness or abnormal reflexes

49 Subdural Hemorrhage Venous bleeding from the bridging veins Slower bleed Symptoms: similar to EDH but no lucid interval

50 Subarachnoid Hemorrhage Thin filmy layer of blood around the brain and cord May be spontaneous or due to trauma Symptoms and Signs: –“the worst headache of my life” –Sudden onset –Nuchal rigidity –Photophobia, nausea, vomiting

51 Intracerebral Hemorrhage May also be spontaneous or traumatic Hemorrhage is deep in the CNS tissue Creates raised intracranial pressure (ICP) due to space-occupying mass Like all of these bleeds, may cause herniation.

52 Diagnostic & Symptomatic Terms Agnosia = inability to process sensory input Aura Autism = withdrawal, inability to communicate Cerebral palsy = developmental defects in brain or birth trauma to brain Closed head injury

53 Diagnostic & Symptomatic Terms Coma Concussion Dementia Dyslexia: inability to learn/process written language Guillain-Barre Syndrome Huntington Chorea: inherited movement disorder (also speech & mental symptoms)

54 Diagnostic & Symptomatic Terms Hydrocephalus Lethargy Neurosis Psychosis Spina bifida/ occulta Meningocele myelomeningocele

55 Diagnostic & Symptomatic Terms Paraplegia / quadriplegia Paresthesia Poliomyelitis Reye Syndrome Sciatica Syncope

56 Diagnostic Procedures Electroencephalography (EEG) Electromyography (EMG) Lumbar puncture (LP) Nerve conduction velocity (NVC) CSF analysis –Glucose concentration –Types of blood or other cells present –Culture to grow bacteria

57 Diagnostic Procedures Cerebral angiography Myelography Scans: CT, MRI, PET

58 Pharmacology Analgesics Anesthetics –Local & general Anticonvulsants –Tegretol, Depakote, Lamictal Antiparkinsonian drugs –Levodopa, Sinemet

59 Pharmacology Hypnotics (sedate) –Barbiturates and valium derivatives Antipsychotics –Haldol, Zyprexia, etc Antidepressants –Paxil, Prozac, TCA’s Psychostimulants –Ritalin


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