CNS Flashcards
Norep and epinephrine action
catecholamines released by nerves in the sympathetic branch of the ANS
Dopamine action
involved in coordination of impulses and responses
absence of dopamine leads to ?
parkinsons
Gamma aminobutyric acid (GABA)
inhibits nerve activity and is important in preventing overexcitability or stimulation such as SEIZURE ACTIVITY
serontonin function
important in the arousal and sleep and in preventing depression and promoting motivation
role of nervous system
controls functions of human body
analyzes incoming stimuli
integrates internal and external responses
function of nervous system
allow movement
allow realization of various sensations
provide response to internal/external stimuli
stimulate learning thinking and emotions
afferent fibers
nerve axons that run from peripheral receptors into CNS
efferent fibers
nerve axons that carry nerve impulses from CNS to periphery and stimulate muscles or glands
dendrite
carries information from one neuron to the next
how is Ach inactivated
cholinesterase
how is norep inactivated
by reuptake
how is serotonin inactivated
reuptake and monoamine oxidase breakdown MAO
dopamine inactivated by?
reuptake or MAO breakdown monoamine oxidase
GABA inactivated by?
enzymatic breakdown
hindbrain controls
breathing
BP
swallowing/vomiting
reticular activating system
Midbrain components
thalamus, hypthalamus, limbic system
thalamus function
sends direct information into the cerebrum to transfer sensations
hypothalamus functions
major sensor of activity in the body temp regulation water balance appetite endocrine function
limbic system action
controls expression of emotions
contains high levels of NT - epinephrine, norep, serotonin
forebrain actions
receives and sends nerve impulses, coordinates speech, communication and facilitates learning.
made up of 2 cerebral hemispheres joined together by corpus callosum
sensory fiber of the spinal nerve is located?
what does it do?
dorsal root
brings the information into the CNS from the periphery
motor fiber of spinal nerves is located and does what?
ventral root
causes movement or reaction
R brain is for
artistic
L brain is
analytical
affect of stress on brain
facilitates learning
increased stress inhibits learning
limbic system role
role in learning
emotions associated with memory and the present have an impact on stimulus response
R sided CVA affects
paralysis on L spatial perceptual deficits quick impulsive behaviors performance memory deficits unable to name items L side visual prob
L side CVA affects
R side paralysis communication language deficits slow cautious behaviors language memory deficits R side visual provs
anxiety definition
state of apprehension tension or uneasiness
stems from anticipation of danger
unknown, unrecognized source of danger
generalized anxiety (GAD)
most common, difficult to control, lasting more than 6 months
situational anxiety
occurs when experiencing daily events in the environment
often does not require pharmacotherapy
panic
characterized by intense feeling of immediate apprehension, impending doom
phobias
fearful feelings attached to situation or object
obsessive compulsive disorders
repetitive behaviors that interfere with normal activities
PTSD
developed in response to reexperience
limbic system functions
also includes anxiety, fear, anger, aggression, remorse, depression, sex drive, euphoria
hypothalamus functions
responsible for unconscious response to extreme stress
connects with reticular formation
associated with fight or flight response
how is insomnia controlled
reticular formation - network of neuron, found along the entire length of brain stem.
reticular activating system is responsible for sleeping and wakefullness; performs an alerting function for the cerebral cortex
how does eeg work
is dx procedure used to examine brain wave patterns
id’s types of sleep -
1. non REM
2. has 4 stages of sleep
3. linked to repair and restoration of physical body
4. if deprived of nREM sleep, may get depressed, fatigue, apathy
REM sleep
rapid eye movement
stage where dreaming occurs
called paradoxical sleep
when deprived, may experience a sleep debt
what happens when one experiences a sleep debt
becomes -
- frightened
- irritable
- paranoid
- emotionally disturbed
insomnia and causes
sleep disorder may be caused by anxiety, stress, cffeine, nicotine, room temp, light, snoring, sleep apnea.
long term may be psychological and physiological
meds used for anxiety and insomnia
anxiolytics
cns depressants
sedatives
hypnotics
benzodiazepines action
bindins with gaba receptor Cl channel molecule, instensify the effects of gaba
barbiturates action
sedative/hypnotic
general CNS depressant
anxiolytic/hypnotic drugs
include choral hydrate, ambien, lunesta, antihistamines (benedryl, phenergan)
benzodiazepine characters
librium, valium
drug of choice for general anxiety and insomnia - onset 30 min
binds with gaba receptor Cl channel molecule
natural receptor, found throughout entire brain
classified as schedule IV drug
some affect REM
may develop tolerance that prolongs use
is CNS depressant
what is valium reversed by
flumazenil (romazicon)
CNS depressant character
sedative hypnotic drug with ability to produce calming effect at low dose, and have sleep inducing effect at high doses
similar to hypnosis - deep sleep
can cause physical, psychological dependence
dose adjustment for children, elderly and african americans.
avoid ETOH, antidepressants, narcotics
Ach action
neurotransmitter that communicates between nerves and muscles
consideration for choral hydrate
taper dose
consideration for paraldehyde
avoid plastic
consideration for rozerem
stay in bed 8 hrs. monitor for depression
nursing considerations for anxiety/insomnia drugs
assess need drug hx hypersensitivity use of ETOH and other CNS depressants ID coping mechanisms client teaching re: drug therapy
MAO inhibitors action
inhibit MAOs
increase biogenic amines at synaptic cleft
TAD action (tricyclic antidepressants)
reduces reuptake of serotonin and norep at synaptic cleft
selective serotonin reuptake inhibitors action
blocks the reuptake of serotonin at synaptic cleft
depression
an emotional disorder/state that is characterized by changes in mood that cause subjective distress and inability to function in age appropriate roles
s/s of depression
low energy
sleep disturbance
lack of appetite
limited libido
inability to perform activities of daily living
overwhelming feelings of sadness, despair, hopelessness, disorganization
types of depression
major dysthymia bipolar as a component of physical illness as a s/e of some drugs - ETOH, antianxiety, non selective anti HTN
neurotransmitters involved in depression
serotonin 5 HT
dopamine DA
norep NE
epinephrine E
which NT’s are biogenic amines
serotonin 5HT and E
etiology of depression and mania
alteration in neuronal and synaptic catecholamine concentrations of norep, DA, and E + serotonin
phenelzine (nardil)
monoamine oxidase inhibitor
used for resistant depression
MAO inhibitor action
inhibits MAO, inhibits breakdown of NE, DA 5HT
allows them to accumulate at synaptic cleft
results in increased stimulation of post synaptic receptor
helps relieve depression
MAOI s/s
tachycardia circulatory collapse seizure coma cerebral hemorrhage
sign of toxicity of MAOI
h/a is 1st sign of OD
what can cause MAOI hypertensive crisis
tyramine (food product) - releases norep. is metabolized in LV and intestinal tract
how does tyramine create hypertensive crisis
by releasing norep - norep is not biotransformed so it BUILDS UP at synaptic cleft.
what other drugs can result in increased norep
OTC cold and flu meds, ie psuedoephedrine
8% of MAOI experience
MAOI food and drink to avoid
aged mature cheese smoked pickled meat fish or poultry aged fermented meats fish or poultry yeast extract red wine italian broad beans
nursing for MAOIs
avoid if cardiac disease due to accum of norep
avoid other sympathetics
monitor LV enzymes
Gi disturbance
combined with insulin or others -> hypoglycemia
tricyclic antidepressant actions
decrease s/s of major depression esp if characterized by anxiety and sleep disturbance childhood enuresis OCD adjunctive analgesics trigeminal neuralgia prophylaxis of migraines
s/e of tricyclics
based on receptors
muscarinic (block) - dry mouth, constip, urin hesistancy, blurred vision, tachycard
histaminergic (block)- sedation, weight gain, hypotension
alpha adrenergic (block)- orthostatic hypotension, smooth musc dilation
serotonergic (effect) - erectile and ejaculatory dysfx, anorgasmia in female
s/s of tricyclic toxicity
seizures
arrhythmia
70-80% die before reaching hospital
tricyclics and elderly
poor choice due to anticholinergic and cardiac effects
time for maoi and tricyclics to kick in
2-4 weeks
tricyclics and SSRI combo effect
dangerous cardiac complications
time takes to clear MAOIs from system
2 weeks
maoi consideration
has many interactions with drugs. need to washout before starting another drug.
strong anticholinergic effect - not for elderly
2nd generation antidepressant
considered superior in terms of s/e but not in terms of efficacy
aka selective serotonin reuptake inhibitors - SSRI
fluoxetine - prozac
special action
preferred for kids with OCD
not fatal in OD
uses of prozac
depression obesity oCD panic attacks social phobia premenstrual dysphoria menopausal sx
where is serotonin found
90% in intestines
what time to take serotonin
in morning - may cause insomnia
other SSRIs
citaloprma - celexa paroxetine - paxil fluvoxamine - luvox sertraline - zoloft escitalopram - lexapro
SSRI s/e
h/a, dizzy, tremor, insomnia, risk for suicide increase
N, diarr, constip, dry mouth
decrease sex fx (paxil) - usually reason for non compliance
interactions of SSRI
increase serotonin with St john’s wort - severe sx include HTN, tachycardia, leading to shock and death
SSRI benefits
better tolerated in elderly
fewer anticholinergic s/e
approved for anxiety and depression
less lethal
bupropion - wellbutrin actions
monocyclic norep, DA reuptake inhibitor (NDRI)
trazodone - desyrel action
serotonin antagonist/reuptake inhibitor (SARI)
has alpha adrenergic effects
chemically unrelated to other groups
venlafaxine - effexor and effexor XR
bicyclic agent
selective 5HT and norep reuptake inhibitor (SNRI)
mirtazapine - remeron action
tetracyclic
noreadrenergic/specific serotonergic antidepressant
antimanic drugs actions
inhibits the release of norep and da
doesn’t inhibit serotonin
LITHIUM
CNS stimulants action
may increase release of cathecholamines from presynaptic neurons
RITALIN
antipsychotics action
DA receptor blockers
THORAZINE
atypical antipsychotics action
block dopamine and serotonin receptors
CLOZAPINE - clozaril
bipolar/mania characteristics
mania - period of extreme over activity and excitement
bipolar - extreme of depression follow by hyperactivity and excitement
may be due to biochem imbalance followed by overcompensation by neurons to re establish stability
narcolepsy definition
daytime sleepiness and sudden periods of loss of wakefullness
due to probs with stim of brain by RAS - reticular activating system
and probs with response to that stim
ADD characteristics
inability to concentrate on one activity for longer than a few minutes
state of hyperkinesia
usually dx in school age children but can also occur in adults
