Medical Terminology

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Medical Terminology

• Nervous System
• Chapter 15

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Nervous System

• Coordinates many activities of the body
• senses changes in internal and external
  environment
• interprets these changes
• coordinates appropriate response in order to
  maintain homeostasis
• When the brain ceases functioning, the body dies

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Structures

• nerve is one or more bundles of impulse carrying
  fibers that connect the brain spinal cord with
  body

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Nervous Tissue

• Neurons - transmit impulses
• sensory (afferent, ascending)
• motor (efferent, descending)
• Neuroglia - support neurons

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Neuron

• dendrites-rootlike structures that receive
  impulses and conduct them to the cell body
• cell body - contains nucleus
• axon-extends away from the cell body and conducts
  impulses away from the nerve cell

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Neuron Anatomy

• Myelin sheath -
• insulation
• accelerates impulse transmission
• appears as white covering
• myelin on axons in brain and spinal cord gives
  white appearance
• unmyelinated fibers, dendrites, and nerve cell
  bodies comprise gray matter of brain and spinal
  cord

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Neuron Anatomy(peripheral nerves)

• Schwann cell
• type of neuroglial cell wrapped around axon
• forms the myelin sheath
• Neurolemma (neurolemmal sheath)
• permits a damaged axon to regenerate
• neurolemma NOT found in Central nerves

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Neurotransmitters

• Synapse- space between two neurons or between a
  neuron and a receptor organ.
• Impulses are passed from one neuron to another at
  a junction called the synapse.
• Electrical current within neuron causes release
  of chemical substance called a neurotransmitter.

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• Neurotransmitter diffuses across the synapse to
  receptor sites on the dendrite of the next
  neuron.
• Generates the next electrical stimulus.
• Terminal ends of the axon release a transmitter
  substance that affects the dendrites of the next
  neuron.
• One way transmission of the impulse is assured
  because only the axons release these chemicals.

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Neuroglia

• gli/o or nerve glue
• neuroglia or glial cells
• astrocytes - blood brain barrier
• oligodendrocytes - facilitate myelin development
• microglia - phagocytic properties
• ependyma - assist in CSF circulation

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Divisions

• Central Nervous System
• brain and spinal cord
• Peripheral Nervous System
• cranial nerves and spinal nerves
• fibers are sensory or motor
• Autonomic Nervous System
• ganglia on either side of the spinal cord
• sympathetic nervous system
• parasympathetic nervous system

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Brain

• Cerebrum
• Cerebellum
• Diencephalon
• Brainstem

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Cerebrum
Cerebrum
Cerebellum
Medulla Oblongata
Two hemispheres divided by a fissure Lobes
frontal, parietal, temporal, occipital Cortex,
gray color
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Lobes

• Frontal
• motor functions
• Parietal
• receives interprets information
• Occipital
• eyesight
• Temporal
• hearing smell

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Cerebellum

• receives incoming messages regarding movement
  within joints, muscle tone, and position of the
  body.
• relay these messages to other parts of brain to
  control skeletal activity
• movement, coordination, balance

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Thalamus

• below the cerebrum
• monitors sensory stimuli by suppressing some and
  magnifying others

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Hypothalamus-a regulator

• Autonomic Nervous System
• emotional responses/behavior
• body temperature
• food intake hunger
• water balance and thirst
• sleep-wake cycles
• endocrine system activity

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Brainstem

• stalk-like portion of the brain
• midbrain - conduction pathways
• pons - nerve cells cross from one side to the
  other
• medulla oblongata - basic life functions
• origin for 10 of 12 cranial nerves
• controls respiration, blood pressure, heart rate

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Spinal Cord

• housed within vertebral column
• continuos with brain stem
• ascending and descending nerve tracts
• protected by CSF and meninges
• gray matter in internal section - not protected
  by myelin sheath
• myelinated white matter in outer area

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Meninges

• dura mater
• epidural
• subdural
• arachnoid
• subarachnoid space
• contains CSF
• pia mater
• blood vessels and lymph

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Bells Palsy

• Facial paralysis
• functional disorder of VII cranial nerve
• asthenia
• keratitis
• dysphasia
• Treatment
• anti-inflammatory drugs

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Cerebrovascular Disease

• Arteriosclerosis
• cerebrovascular accident (CVA, apoplexy)
• ischemia
• transient ischemic attack
• hemiparesis
• hemiplegia
• aphasia
• ataxia

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Seizure Disorders

• Epilepsies
• dysrhythmias in the brain
• etiology brain injury, congenital anomalies,
  metabolic disorders, brain tumors
• Convulsions

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Parkinsons Disease

• Progressive neurological disorder
• deterioration of portion of brain controlling
  movement
• bradykinesia, hypokinesia, tremors, shuffling
  gait.
• Treatment l-dopa

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Multiple Sclerosis

• Progressive degenerative disease of CNS
• Inflammation, hardening, and loss of myelin
  throughout spinal cord and brain
• Impeded transmission of electrical impulses
• tremors, muscle weakness, slowness of movements
• etiology autoimmune, or slow virus

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Alzheimers Disease

• Progressive neurological disorder
• plaques develop in cerebral cortex
• memory loss, cognitive decline, and personality
  changes
• leading cause of senile dementia
• research some meds prevent breakdown of brain
  chemicals

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Oncology

• Intracranial tumors
• primary sites
• metastatic sites
• Signs and Symptoms
• headaches
• papilledema
• personality changes

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• Agnosia
• asthenia
• ataxia
• cerebral palsy
• closed head trauma
• coma
• concussion
• Guillian-Barre syndrome
• herpes zoster (shingles)

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• Huntingtons chorea
• hydrocephalus
• lethargy
• neural tube defect
• paraplegia
• paresis

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• Paresthesia
• poliomyelitis
• quadriplegia
• Reyes syndrome
• sciatica
• syncope
• vasovagal
• transient ischemic attack (TIA)

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• Cerebral angiography
• echoencephalography
• electroencephalography (CCG)
• myelography
• computed tomography (CT scan)

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Surgical and Therapeutic Procedures

• Cryosurgery
• spinal puncture, spinal tap
• trephination
• vagotomy

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Pharmacology

• Analgesics
• \anticonvulsants
• antidepressants
• hyponotics
• opiates
• psychtropic drugs
• sedatives
• tranquilizers

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Abbreviations

• ALS
• ANS
• CNA
• CP
• CSF
• CT scan
• CVA
• CVD

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Abbreviations

• EEG
• ICP
• LP
• MRI
• MS
• R/O
• TIA

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• End
• Chapter 15
• Nervous System