Nervous System Flashcards
Define consciousness and list it’s compartments
It is the state of awareness of yourself and your environment, as well as being able to orient new stimuli
2 compartments: arousal and awareness
Define arousal (wakefulness)
Maintained by the Reticular Activating System (RAS)
Loss if consciousness indicated injury directly to RAS or to both hemispheres
Injury to one hemisphere and not to RAS has no loss of consciousness
Which parts of the brain are involved with the RAS
The brain stem, medulla, thalamus, and functioning cerebral cortex
Describe Awareness (content and cognition)
Includes all cognitive functions:
Awareness of self and environment, moods, reasoning, judgement
What are the 3 main cognitive functions of awareness and what do they mean
Selective attention: ability to select specific info to process
Memory: ability to store and retrieve info
Executive attention: ability to maintain attention, remember instructions, self control, etc
What are the 5 levels of consciousness? Which are levels vs symptoms?
Coma (completely out)
Stupor (arousable to pain)
Obtundation (lower arousal level, sleepy)
Delirium (restless, hallucinations, delusions)
Confusion (disoriented, fuzzy, poor response)
Describe the Glasgow coma scale and the 3 responses
Scale used to determine level of consciousness
Eye opening, verbal response, and motor response
<8 is severe head injury while 15 is normal
Define brain death
Irreversible loss of brain function
Homeostasis cannot be maintained
Recovery not possible
Which criteria determines brain death?
Underlying pathology
Deep coma with no motor reflexes
No brain stem reflexes
Cannot breathe on their own
Lack of other causes
What is a persistent vegetative state
Complete unawareness of self or environment
Sleep wake cycles are present
Brain stem reflexes work
Describe a minimally conscious state
One may follow simple commands, gesture, or speak, but are not consistent
Describe locked in syndrome
Complete paralysis except for eye movement
Fully conscious, cannot communicate
What is cheyne strokes breathing
Alternating apnea and tachypnea due to co2 levels in blood
What is neurogenic hyperventilation
> 40 breaths per minute when there is an Injury to the midbrain
How do pupils change with light? What can this tell us?
Pupil response can range in combination of fixed, dilated, pinpoint, and unequal
Can help determine location and extent of brain damage
Describe the Dolls Eye response
If you turn the head, the eyes should stay looking straight.
It is abnormal if the eyes follow the head or move independently
What are the 3 manifestations of deteriorating brain function
Patterns of breathing, pupillary changes, oculomotor response, and motor responses
What are the main 2 motor responses seen in comatose patients? Describe them and their causes
Decorticate - upper extremities are flexed up, lower extremities are extended
Occurs with severe cerebral hemisphere damage
Decerebrate - extended extremities, clenched jaw, extended neck
Occurs with brain stem lesions
Define seizure disorders. What do they involve?
A sudden, explosive, disorderly discharge of cerebral neurons
Involves motor, sensory, autonomic, or psychic manifestations
What do minor vs major seizures look like? How are they caused?
Minor
Manifests as staring spells, no body shaking, may go unnoticed
Major
Produce convulsions: jerky, muscle contraction - relaxation cycles
Accused by cerebral lesions, biochemical disorders, cerebral trauma, or epilepsy
Define data processing deficits
Problems with recognizing and processing sensory information
Define agnosia, hemineglect, and dysphasia.
Failure to recognize the form of objects, usually affects one sense (eg. Can recognize by feel but not by looking)
Inability to attend to/react to stimuli from side with damage. Won’t track, orient, or reach to that side.
Understanding and use of symbols is wrong or lost. Using wrong words, not understanding proper meaning
What are the causes of agnosia, hemineglect, and dysphasia?
Caused by damage to a specific part of the brain
Injury to one side of the brain
Caused by dysfunction in left hemisphere
Describe Aphasia and differentiate between Broca’s and Wernike’s
Aphasia is the inability to communicate. It’s used interchangeably with dysphasia
Broca’s: expressive
Difficulties finding the correct word
Caused by damage in language section of the brain
Wernike’s: Receptive
Individual uses nonsense words in long sentences
Caused by damage to part of brain responsible for language comprehension
What does it mean when there is a disruption of neuromotor functions?
There is a disruption of any area in the NS that influences movement
What are the 3 alterations in neuromotor function?
Alterations in muscle tone
Alterations in movement
Alterations in complex motor function
Describe muscle tone and how alterations are caused
Muscle tone is the normal state of muscle tension which allows for controlled movement and posture maintenance.
Alterations can be caused by injury to any section of the motor pathway: peripheral nerve, NMJ, spinal cord, or brain
What are the symptoms of muscle tone alterations?
Depends where damage is
UMN injuries cause rigidity
LMN injuries cause flaccidity
Rigid vs flaccid
Define paresis
Muscle weakness due to alteration in how motor units are activated
Describe paralysis and how it occurs
Loss of motor neuron function so muscle groups cannot overcome weight of gravity (total movement loss)
Caused by lesions in upper and/or lower motor neurons
Describe the types of paresis and paralysis based on lesion location
