1. Chapter 14 Medical Terminology
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 Neuroglia
Transmit impulses (conduct)
Sensory neurons (afferent)
Motor neurons (efferent)
Mixed (both afferent and efferent)
Neuroglia
Supporting cells

4. Neurons: Structure Cell body Dendrites Axons
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 Peripheral nerve (PNS)
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 Axon terminal Neurotransmitter
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 Cerebrum: Functions 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 Arachnoid Pia 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 Encephalitis
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 Anticonvulsants
Local & general
Anticonvulsants
Tegretol, Depakote, Lamictal
Antiparkinsonian drugs
Levodopa, Sinemet

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