Chapter 43 Assessment Of The Nervous System Flashcards
Peripheral nervous system consists of
12 cranial nerves
31 pairs of spinal nerves
Sympathetic
Parasympathetic
Central nervous system consists of
Brain and spinal cord
Role of neurons
Motor (efferent): carry impulses away from CNS
Sensory (afferent): carry impulses towards CNS
Process information
Retain information
Myelin sheath
White lipid covering
Speeds transmission of impulses
White matter
Non-myelinated
Gray matter
Synaptic knob
Distal end of each axon
Manufacture, store, and release neurotransmitter
Neuroglial cells provide:
Protection Structure Nutrition Part of blood brain barrier Help regulate CSF
Meninges
Cover brain and spinal cord
Three layers all made of connective tissue
Dura mater
Outermost meninges
Very tough
Arachnoid
Middle meninges
Cobweb in appearance
Pia mater
Innermost meninges
Very thin and delicate
Tightly bound to brain and spinal cord
Subarachnoid space
Layer between arachnoid and pia mater
Contains CSF and blood vessels
Cerebrospinal Fluid (CSF)
Clear fluid derived from blood stream
Adds additional protection and lubricates the spinal cord and brain
Contains nutrients needed by the brain and spinal cord
Also contains waste products that will be brought to the blood stream and excreted by the body
Cerebrum
Outer other part of the brain
Left and right hemispheres
Hemispheres divided by longitudinal fissure
*LARGEST PART OF THE BRAIN
*Controls intelligence, creativity, and memory
Frontal lobe
Anterior most lobe
Primary motor area for muscular contraction
Personality, behavior, emotion, intellectual function, *judgement
Parietal lobes
Sensation
Occipital lobes
Vision
Temporal lobe
Hearing (does not cross sides: right side=right ear)
Smell
Gustatory area
Located in these parietal lobes where it is overlapped by the temporal lobes
Usually located on left side
Broca’s area
Motor speech: the act of physically talking
If a pt is damaged, they may know what they want to say but different words will come out
Gnostic area
Stores complex memory patterns
Wernicke’s area
Language COMPREHENSION
Which part of the brain makes us human?
Central cortex
Thalamus
Receives all sensory information and sends it to the appropriate lobe
Brain stem contains:
~Midbrain-voluntary motor nerve cells, visual and auditory reflex centers, narrow channel for CSF
~Pons-helps to regulate breathing movements
~Medulla oblongata-cardiac center, vasomotor center, respiratory center
Cerebellum
~Another motor area of the brain
~Subconscious contractions of skeletal muscles to maintain: coordination, posture, balance
~Impulses from inner ear sent here: equilibrium
Spinal cord nerves have 2 main functions
Conduction of impulses going to and from brain
Reflex center
Spinal cord location
Begins at foramen magnum and ends at the first lumbar vertebrae
Voluntary nervous system
Goes to skin and muscles
Involved in conscious activities
Autonomic nervous system
~Automatically takes care of body functions
~Sympathetic nervous system (fight for flight)
~Parasympathetic nervous system (active under ordinary relaxed conditions)
Nerve impulse: conduction
Sending a message
It all works with potassium and sodium
The resting membrane of a nerve cell
DOES NOT allow potassium or sodium to diffuse across it
Minimum threshold
The minimum amount of stimulus to cause an action potential
Refractory period
Is small amount of time necessary to restore the cell back to its resting membrane
Cannot respond to the second stimuli until this is done
All or none principle
If the stimulus is strong enough to cause an action potential:
- The action potential will go out one speed
- A stronger stimuli cannot speed up the process
Saltatory conduction
Deals with nerve cells that have myelin
Greatly speeds up the process
Acetylcholine
Work on skeletal muscles
Norepinephrine
Smooth and cardiac muscle
Epinephrine
Behavior and mood
Dopamine
Emotional responses and has an effect on the cardiac and circulatory system
Serotonin
Regulates temperature, sensory perception, mood, and onset of sleep
GABA
Slows everything down
~inhibits the excessive discharge of neurons
Endorphins
Inhibits the release of sensory pain neurotransmitters
Hypoactive deep tendon reflexes and loss of vibration sense
Can impair balance: need to look at their feet placement as they walk
A change that happens with age
Some changes with aging
- Changes in pain perception
- Changes in sleep patterns: require less sleep, but more frequent rest periods
- Increased risk for infection
A change in the LOC is usually the first indication of
A decline in central neurological function
A complete neurological assessment is done three times:
Laying, sitting, standing
One issue with glaucoma medication:
It may dilate the eye and slow the pupil response
When testing the patient’s memory function
Ask questions regarding their date of birth, city of birth, or anything that can be verified
Higher levels of cognition
Favorite hobbies, current events, name of last few presidents
Abstract reasoning: meaning of Proverbs
Judgment: rational decisions in dealing with symptoms
Romberg’s test
Patient stands with eyes closed
Loss of balance is positive Romberg’s sign (difficulty with proprioception)
Patients with decreased sensation are instructed to
Look at their feet when they walk
Hyperactive reflexes
Upper motor neuron disease, tetanus, hypocalcemia
Hypoactive reflexes
Lower motor neuron disease, DM with nerve damage, hypothyroidism, hypokalemia
Decortication
Arms wrists and fingers are flexed
Internal rotation and plantar flexion of feet
Corticospinal pathways are interrupted (lesions on the spinal cord)
Decerebration
Extension of arms and legs
Pronation of arms and plantar flexion
Obsithotonos (body spasm in which body is bowed forward)
Seen with disfunction of brainstem
Glasgow coma scale
The higher the score the better
Cerebral angiography: post procedure:
Circulation of extremity: both at site, and downstream from site
PET scan
No alcohol, caffeine, and tobacco 24 hours prior to test
NPO 4 to 12 hours before test
No glucose solution 4 to 12 hours before the test
Follow up: increase fluid intake
Contraindicated in women who are breast-feeding
What is important to have before getting a lumbar puncture?
Signed informed consent
Normal total proteins
15-45 mg/dL (up to 70 mg/dL in older adults)
Immune gamma globulin (IgG)
- The most important protein
- Normal: 3% to 12% of total protein
- More than 12% of total protein: multiple sclerosis, neurosyphilis, or viral infection
Normal glucose
50-75 mg/dL or 60% to 70% of blood glucose level
Less than 50 mg/dL : usually accompanied by the presence of pathologic organisms
Electroencephalography (EEG)
Graphically records electrical activity of cerebral hemispheres
Patient must be sleep deprived before procedure
Anticonvulsants may be withheld
Hyperventilation during the test: cerebral vasoconstriction and can induce seizure activity
