The
Nervous
System
Diseases, Conditions, and
Syndromes of the Nervous System
2003-2004
Overview
 The Nervous System controls and
coordinates all the functions of the
body.
 The Nervous System consists of two
main sub-divisions:


Central Nervous System (CNS)
Peripheral Nervous System (PNS)
• The Peripheral Nervous System is
divided into two sub-divisions:


Somatic- voluntary
Autonomic- involuntary
Regents Biology
2003-2004
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http://inside.salve.edu/walsh/cns_pns.jpg
2003-2004
Structure and Function of the Neuron
 Neuron is the scientific name for a Nerve
Cell.
 Neurons consist of 3 basic structures:



Cyton, or cell body.
Dendrites- receive messages, impulses, and
send them to the cell body.
Axons- send messages away from the cell
body.
• Nerve impulses travel from one neuron to
another across synapses, or spaces in
between the cells.
• The “jumping across” the synapse is
facilitated (helped) by chemicals called
Neurotransmitters.
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2003-2004
Parts of the Cell
 Dendrites – Branched
 A Neuron
parts of a neuron that
receive impulses from
other neurons.
 Cyton- Contains
cytoplasm and the
nucleus. Impulses pass
through here to the
axon.
 Axon- Single long fiber
that carries impulses
away from the cell body.
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2003-2004
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2003-2004
Types of Brain Injury
Altered Consciousness

Definition: condition of being less responsive to and aware of
environmental stimuli (Smeltzer & Bare, 2004).
Unconsciousness

Definition: physiological state in which the client is
unresponsive to sensory stimuli and lacks awareness of self and
the environment (Hickey, 2003)


Can be brief, lasting a few second to a few hours or
longer.
To produce unconsciousness a disorder must:
1. Disrupt the RAS which extends up to the thalmus.
2. Significantly disrupt the function of both cerebral
hemispheres
3. Metabolically depress overall brain function
Coma
Coma is a prolonged state of unconsciousness in which the client
is unaware of self or the environment for sustained periods
of time from hours to months. (Hickey, 2003)
Because of:
-disorders that affect BOTH cerebral hemispheres
- disorders that affect any part of the RAS
- direct compression on parts responsible for conciousness
ie: hemorrhage, tumors
- metabolic disorders (hypoglycemia, hypoxia)
- toxins
** Duration of coma is associated with mortality &
outcome****
Reduction in level of consciousness may be caused
by extracranial or intracranial causes.
Assessment



Glasgow Coma Scale
Mini-mental
Diagnostic Tests
– CT and MRI
– Lumbar Puncture
– EEG
– Laboratory Tests

Tests for Abnormal Reflexes
– Oculocephalic Reflex Response
– Oculovestibular Reflex Response
GLASGOW COMA SCALE SCORE (GCS)
Eyes
Motor
1 Closed at all times
2 Opens to pain
3 Opens to voice command
4 Open spontaneously
1 No response
2 Extension (decerebrate)
3 Flexion posturing (decorticate)
4 Flexion withdrawal
5 Localizes painful stimulus
6 Obeys commands
Verbal 1 No response
2 Incomprehensible sounds
3 Inappropriate words
4 Disoriented and converses
5 Oriented and converses
A score of 10 or
less indicates a
need for emergency
attention
15 (top score)
A score less than 7
is interpreted as
coma
Diagnostic Tests




CT or MRI: data on structural causes such
as tumor or hemmorhage.
-Metabolic – will be unremarkable
LP: infection or bleeding (cloudy or
bloody)
EEG: structural or metabolic, seizure
activity
Lab tests: LFTs, kidney function, glucose
levels, toxicology, ABGS
Types of Head Injury



Scalp injury: minor injury
resulting in laceration, abrasion
& hematoma
Skull injury: may occur with
or without damage to brain.
Brain injury
Head Injuries

Closed or blunt: blunt object damages
the brain and its coverings without actually
perforating the skull or dura.
 Penetrating: when the skull and brain
are directly lacerated by an object such as a
bullet, or piece of bone.

Coup-Contrecoup Injuries: same
blow causes injury on opposite sides
of the brain.
Skull Fractures
Otorrhea

Linear Skull Fracture: is a break in the continuity of the
bone, appear as thin lines on X-ray.

Depressed Skull Fracture - The broken piece of skull
bone is pressed towards or embedded in the brain.

Comminuted and Compound Skull Fracture - The scalp
is cut and the skull is splintered, multiple fractures.

Basilar Skull Fracture
The skull fracture is located at the base of the skull and
may include the opening at the base of the skull
Stroke
 Occurs when
there is not
enough oxygen
going to the
brain.
Regents Biology
2003-2004
Autism
Overview
Autism is a developmental disorder that appears in the first 3 years of life,
and affects the brain's normal development of social and communication
skills.
Symptoms
Most parents of autistic children suspect that something is wrong by the
time the child is 18 months old and seek help by the time the child is age 2.
Children with autism typically have difficulties in:
•Pretend play
•Social interactions
•Verbal and nonverbal communication
Some children with autism appear normal before age 1 or 2 and then
suddenly "regress" and lose language or social skills they had previously
gained. This is called the regressive type of autism.
People with autism may:
•Be overly sensitive in sight, hearing, touch, smell, or taste (for example,
they may refuse to wear "itchy" clothes and become distressed if they are
forced to wear the clothes)
•Have unusual distress when routines are changed
•Perform repeated body movements
•Show unusual attachments to objects
Polio
 Viral disease of the central nervous
system that can cause paralysis.
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2003-2004
Meningitis
 Is an inflammation
of the membranes
that surround the
brain and spinal
cord.
 Disease is caused
by bacteria, or a
virus.
 Symptoms – Very
bad headache
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2003-2004
Cerebral Palsy
 Congenital
disease
 (born with)
 Disturbance of
motor functions
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2003-2004
Herniated Disk
 Disk in vertebra
moves up
against the
spinal nerves.
Very painful
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2003-2004
Alzheimer's Disease
Parkinson’s disease
Multiple Sclerosis (autoimmune)
Guillain-Barre Syndrome (autoimmune)
Alzheimer’s disease is an irreversible,
progressive brain disease that slowly destroys
memory and thinking skills.

AD is the most common cause of dementia among people age 65 and older

For every 5-year age group beyond 65, the percentage of people with AD doubles.

In 2006, there were 26.6 million sufferers worldwide.

The annual cost of Alzheimer’s disease care in the U.S. is more than $100 billion

Age
Apoe E4 Gene
Family History
Down Syndrome
Head Injury
mild cognitive impairment(MCI)

Education Level

Gender





The brains of people with AD have an abundance of two
abnormal structures:


beta-amyloid plaques, which are dense deposits of protein and
cellular material that accumulate outside and around nerve cells
neurofibrillary tangles, which are twisted fibers that build up
inside the nerve cell
An actual AD plaque
An actual AD tangle




Signs of AD are first noticed in the cortex,
then proceed to the hippocampus.
Affected regions begin to shrink as nerve
cells die.
Changes can begin 10-20 years before
symptoms appear.
Memory loss is the first sign of AD.
PARKINSON’S DISEASE
Imbalance of dopamine and
acetylcholine in Parkinson's disease.
PARKINSON'S DISEASE
Cellular degeneration of
dopamine-producing
cells in the part of the
basal ganglia called the
substantia nigra, results
in depletion of
neurotransmitter
Dopamine.
Often presence of “Lewey
Bodies”
Classic symptoms
CHARACTERISTICS
 Slowly progressive regardless of treatment
 "Shaky palsy" tremor/ rhythmic tremor
(1st symptom)
 Usually idiopathic
 150 per 100,000
 After age 50
 LE 25 yrs post onset
MULTIPLE
SCLEROSIS
Multiple Sclerosis
 Chronic demylinating disease that affects the
myelin sheath of neurons in the CNS
 Plaque develops on myelin causing
inflammation, edema and eventual scarring.
 Clinical course is unpredictable combinations
of sensory, motor, & coordinative disfunctions
followed by exaserbations followed by partial or
complete remission.
Manifestations








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Clinical manifestations vary according to area of
demyelination and affected body system.
About 20% have a mild form with only a few mild
attacks that do not result in progression
80% of clients lead active & productive lives
Most clients are able to live a normal life span
Cause of death is usually infection.
Weakness/fatigue or tingling sensations of one or more
extremities (involvement of cerebrum or spinal cord)
Diplopia
Incoordination (cerebellar involvement)
Bowel/bladder dysfunction (spinal cord)
Constipation
Depression and/or euphoria, emotional instability (disease or
reaction?)