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Chapter 4
Biological Basis for Understanding
Psychopharmacology
Psychiatric illness
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Biological basis related to number of factors
-Genetics, neurodevelopment, drugs, infections,
psychosocial experience; there will eventually be an
alteration in cerebral function that accounts for
disturbances in pt’s behavior and mental experience
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Psychiatric Mental Health Nursing
-Goal is to understand biological basis of normal and
abnormal brain function and apply this understanding
to care of individuals treatment with drugs
Brain structures and functions
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Composed of interconnected specialized nerve cells
called neurons
Cerebrum: mental activities, conscious sense of being,
conscious perception of external world, emotional status,
memory, voluntary motor ability, language and ability to
communicate
4 major lobes
-Frontal: motor strip, supplemental motor area, Broca
area (voluntary movement and language) + prefrontal
cortex (goal directed activities
-Parietal: sensory and motor
-Occipital: vision
-Temporal: auditory, memory processing and emotion
Brain structures and functions
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Subcortical structures
-Basal ganglia (4)
Striatum, pallidum, substantia nigra + subthalmic
nucleus
 Gray matter nuclei allows for smooth integration of
emotions, thoughts + physical movement
 Play a role in motor responses via extrapyramidal
motor system which relies on neurotransmitter
dopamine to maintain proper muscle tone and
motor stability
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Brain structures and functions
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Thalmus
-Major sensory relay station to cortex
Hypothalmus
-Maintains homeostasis (temp, BP, perspiration, sex drive, hunger,
thirst, circadian rhythms)
-Send instructions to the autonomic nervous system which is
divided into sympathetic and parasympathetic systems
-Sympathetic: increases HR, RR, BP to prepare for “fight or
flight.” Highly activated by amphetamines and cocaine,
withdrawal from alcohol, benzodiazepines and opiates
-Parasympathetic: decreases HR +begins digestion
Brainstem: made up of midbrain, pons + medulla
-Controls vital life functions
Cerebellum (located posterior to brainstem)
-Controls balance and smooth muscle movement
Neuroimaging of brain structures
and functions

Measure structure, function and chemistry in
brain
-CT scan: series of x-rays to view brain structure
-MRI: uses magnetic field and radio waves-higher
resolution than CT and can visualize smaller brain
lesions
-PET: uses radioactive material to assess regional brain
glucose and to secure images brain function (use in
schizophrenia, depression and OCD)
-SPECT: similar to PET, poor resolution, less cost
-fMRI: relies on magnetic properties , use is similar to
PET, higher resolution than PET.
Cellular composition of the brain
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Neurons (nerve cells)
-Brain is composed of 100 billion
-Essential feature of neurons is ability to conduct
electrical impulse from one end of cell to other
(neurotransmission)
-Electrical signals within neurons are converted at
synapse into chemical signals through release of
molecules called neurotransmitters, which elicit
electrical signals on other side of synapse, which
enable information processing in the brain
Neurotransmitters
Chemical messengers between neurons by which one
neuron triggers another
-4 major groups in brain
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Monoamines
-Dopamine, norepinephrine, serotonin, histamine
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Amino Acids
-GABA, glutamate
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Cholinergics
-Acetylcholine
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Peptides
-Substance P, somatostatin, neurotensin
How psychotropics work
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Produce effects through alteration of synaptic
concentrations of neurotransmiters (dopamine,
acetylcholine, norepinephrine, serontonin,
histamine, GABA or glutamate)
Changes results from receptor antagonists
(interfering with an action), agonists (mimicking
an action), interference with neurotransmitter
reuptake, enhancement of neurotransmitter
release, or inhibition of enzymes
Standard or typical antipsychotics
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Typical (Neuroleptics):
-Cause significant neurological effects
-Also known as dopamine receptor antagonists (DRA)
because they bind to D2 receptors and reduce
dopamine transmission
-D2 blockade can cause extrapyramidal side effects
(dystonia, akathesia, tardive dyskinesia and
neuroleptic malignant syndrome)
 Chlorpromazine (Thorazine) low potency
 Haloperidol (Haldol) high potency
 Fluphenazine (Prolixin) high potency
Atypical antipsychotics

Known as serotonin dopamine antagonists
(SDA’s) because they have higher ratio of
serotonin type D2 receptor blockade than typical
DRA’s
-Clozapine (Clozaril): one of 1st, not used due to
agranulocytosis
-Olanzapine (Zyprexa): causes weight gain and
necessitates metabolic monitoring (wt, BMI, waist
circumference, fasting glucose, lipid profile)
-Risperidone (Risperdal): can cause low BP/sedation