Chapter 7: Biological Foundations of Psychiatric Nursing

Cerebrum

largest brain region

cortex (gray matter) is 80% of mass

Structure

Two hemispheres connected by the corpus callosum for rapid info exchange 

Left hemisphere

Dominant in 95% of people

Controls speech and analytical processing

Right Hemisphere

Controls nonverbal communication and spatial orientation 

Frontal Lobe

Primary Functions: motor, speech, personality, executive function

Key areas: prefrontal cortex, broca area

Parietal Lobe

Primary Functions: sensory, spatial direction, calculation 

Key areas: post central gyrus (somasensory

Temporal Lobe

Primary Functions: auditory/olfactory processing, memory, mood

Key areas: Wernicke area, hippocampus

Occipital Lobe

Primary Functions: visual integration, facial recognition

Key areas: primary visual area

Limbic System

Modulates emotions, drives, and instincts

Basal Ganglia

Motor control, dysfunction causes involuntary movements

Extrapyramidal Motor System

Controls muscle tone and reflexes

Brain Stem

Source of neurochemicals (serotonin); mediates emotional dysfunction symptoms

Cerebellum

Controls movement and posture

Neuroplasticity

Brain’s ability to adapt, reroute signals, and learn 

Highest in infancy/childhood; decreases w/age

Synaptic Transmission Process

Stimulus Ca+ ion channels to open

Release: neurotransmitters released from presynaptic neuron 

Binding: lock and key binding to postsynaptic receptors  

Termination: activation ends via reuptake or enzymatic degradation

Major Neurotransmitters

acetylcholine

Dopamine

Norepinephrine

serotonin

GABA

Glutamate

Acetylcholine

cholinergic

Function: memory, wakefulness, rest and digest

Dopamine

Biogenic Amine

Function: motor, mood, reward system

Norepinephrine

biogenic amine

Function: learning fight for flight

Serotonin

biogenic amine

Function: appetite, sleep, mood, pain

GABA

amino acid

Function: inhibitory, controls anxiety/seizures

Glutamate

amino acid

Function: excitatory, sensory organs

Polygenic Nature

Psychiatric disorders involve multiple genes working together

Genetic Susceptibility

Predisposition + Environmental influence (stress, infection, trauma)= Disorder development 

Ex. when mother is carrying

Epigenetics

How environment changes gene expression w/o altering DNA code

Family Studies

1st and 2nd degree relatives

twin studies

concordance in monozygotic vs dizygotic twins

Adoption Studies

impact of different environments

Psychoneuriummunology (PNI)

Relationship between immune, nervous, and endocrine systems

Stress affects NK cells → increased disease susceptibility

Gut-Brain Axis

Enteric Nervous System (ENS): Communicates w/CNS via the vagus nerve

Microbiota: Produce dopamine/serotonin; influence neurogenesis and disorders (anxiety, autism)

EEG

neurophysiological Test

measures cortical electrical activity (seizures, metabolic issues)

Polysomnography

neurophysiological Test

sleep EEG (identifies REM latency/delta sleep issues in depression)

Evoked Potentials

neurophysiological Test

electrical response to sensory stimuli

Structural Brain Imaging

MRI, CT

view anatomy/injury

Functional Brain Imaging

fMRI, PET, SPECT

view blood flow/processing

Routine Lab Tests

Thyroid, electrolytes, hepatic enzymes (rule out physical mimics)

Challenge Lab Tests

include symptoms (lactate/caffeine) to study panic

Executive Functioning

Frontal lobe impairment requires nurse to adjust care schedules and assist w/complex tasks

Sleep Hygiene

Understanding that norepinephrine activations (anxiety) physiologically prevents rest

Patient Education

Explaining neuroplasticity to encourage therapy engagement 

Discussing role and limitation of biological markers