Biologic PPT

1,425
-1

Published on

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
1,425
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
26
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Biologic PPT

  1. 1. The Biologic Foundations of Psychiatric Nursing Chapter 8
  2. 2. Biological Basis of Behavior • Most human behaviors have a biological basis. • Symptom expression = behavioral symptoms = brain dysfunction
  3. 3. Foundation of Biological Basis of Behavior • Animal modeling – Resembles humans in structure, function or genetics – Can induce disorders – Usually rats, mice • Genetics – Populations genetics – Risk factors
  4. 4. Risk Factors • Increased risk for developing a disorder • May be genetic, biological, psychologic or social
  5. 5. Current Approaches to Studying Neuroanatomy and Neurophysiology • Comparative – compared with other life forms • Developmental – changes in nervous system throughout the life span • Cytoarchitectonic – distribution and arrangement of cells within various parts of brain • Chemoarchitecture – identification of neurotransmitters or chemicals • Functional – localization of functioning
  6. 6. Plasticity • Ability of the brain to change • Compensates for loss of function in specific area • Nerve signals may be rerouted. • Cells learn a new function. • Nerve tissues may be regenerated.
  7. 7. Structural Neuroimaging • Allows for visualization of the brain • Commonly used techniques – Computed tomography (CT) • X-rays and computers • Iodinated contrast materials administered IV – Magnetic resonance imaging (MRI) • Place patient in long tube with magnets • Can reconstruct three-dimensional structures • More costly and complicated than CT
  8. 8. Functional Neuroimaging • Measurement of physiologic activities • Two primary imaging procedures (Both require administration of radioactive materials.) – Positron emission tomography (PET) – Single photon emission computed tomography (SPECT) – Patient can perform functions during this time.
  9. 9. Neuroanatomy of the CNS • Cerebrum • Left and right hemispheres • Lobes of the brain – Frontal – Parietal – Temporal – Occipital – Association Cortex
  10. 10. Neuroanatomy Subcortical Structures • Basal ganglia • Limbic system • Hippocampus • Thalamus • Hypothalamus • Amygdala • Limbic midbrain nuclei
  11. 11. Neuroanatomy Other Important CNS Structures • Extrapyramidal system • Pineal body • Locus ceruleus • Cerbebellum
  12. 12. Autonomic Nervous System (Fig. 8.7) • Neurons of ANS – Efferent or motor system nerves (nerves moving away from CNS) – Afferent or sensory (nerves moving toward CNS) • Sympathetic • Parasympathetic
  13. 13. Neurons and Nerve Impulses (Fig. 8.8) • Soma – cell body – nucleus – ribosomes – endoplasmic reticulum – Golgi apparatus – vesicles – lysomes – mitrochodria • Axons – conducts impulses • Dendrites – receives impulses
  14. 14. Synaptic Transmission • Neurotransmitters - Small molecules directly or indirectly responsible for opening or closing ion channels • Neuromodulators - Chemical messengers that make the cell membrane more or less susceptible to effects of primary neurotransmitter • Influx of CA++ into the neuron stimulates release of neurotransmitters into synapse. • Receptors - Proteins for specific neurotransmitter, “lock and key”
  15. 15. Fate of Neurotransmitter After Action • Removed by natural diffusion • Reuptake into presynaptic terminal
  16. 16. Receptors • Sensitivity can change, developing either a greater or lesser response to the neurotransmitter. • Receptor subtypes – Each major neurotransmitter has several different subtypes for the chemical, allowing for different effects on the brain. – Each major neurotransmitter has several different subtypes (e.g., Dopamine, D1, D2, etc.).
  17. 17. Neurotransmitter Criteria • Synthesized inside the neuron • Present in the presynaptic terminal • Released into the synaptic cleft, causing a particular effect on the postsynaptic receptors • An exogenous form of the chemical is administered as a drug causes identical action. • Chemical is removed from the synaptic cleft by a specific mechanism.
  18. 18. Neurotransmitters • Excitatory – causes activity to occur • Inhibitory – causes activity to decrease
  19. 19. Cholinergic Neurotransmitter Acetylcholine (ACh) • Primary neurotransmitter of parasympathetic nervous system • Part of sympathetic system • Excitatory neurotransmitter • Follow diffuse projections throughout the cerebral cortex and limbic system • ACh involved in higher intellectual functioning and memory
  20. 20. Cholinergic Receptor • Muscarinic receptors – Many psychiatric medications block the muscarinic receptors (anticholinergic). – Blocking the effects causes common side effects, including: • dry mouth, blurred vision constipation, urinary retention, and tachycardia • Nicotinic receptors
  21. 21. Biogenic Amines • Synthesized from tyrosine – Dopamine – Norepinephrine – Epinephrine • Synthesized from tryptophan – Serotonin • Synthesized from histidine – Histamine
  22. 22. Neurotransmitters • Acetylcholine – High intellectual functioning • Dopamine – Mesocortical and Mesolimbic • Cognition, memory, emotion, auditory reception – Nigrostriatal • Influences extrapyramidal system • Subserve voluntary movement • Allows involuntary movement – Tuberoinfundibular • Endocrine functions
  23. 23. Dopamine (DA) • Excitatory neurotransmitter • Involved in cognition, motor and neuroendocrine functions • Decreased in Parkinson’s, increased in schizophrenia • Pathways (Figure 8.11) – Mesocortical, mesolimbic – Nigrostriatal – Tuberoinfundibular
  24. 24. Dopamine Receptors • Five subtypes • D1 and D5 - cortex, hippocampus and amygadala • D2 found in nigrostriatal system • D4 found mainly in cortex
  25. 25. Norepinephrine • Widely distributed in the peripheral nervous system • Excitatory neurotransmitters play a major role in mood states. • Decreased NE associated with depression, increased NE associated with mania • Pathways are named “noradrenergic” and are less delineated than dopamine pathways. • Pathways in locus cereulus so involve in sleep, wake
  26. 26. Neurotransmitters • Norepinephrine (Fig. 8.12) – Sympathetic nervous system functions – Sleep, wakefulness – Reinforce learning • Serotonin (5-HT) (Fig. 8.13) – Sleep, wakefulness – Control of food intake, hormone secretion, sexual behavior, mood and emotion, thermoregulation
  27. 27. Serotonin (5-HT) • Excitatory neuron distributed within the cerebral cortex, limbic system, an basal ganglia, hypothalamus and cerebellum. • Involved in regulation of emotion, cognition, sensory perceptions, sleep and appetite. • Involved in control of food intake, hormone secretin, sexual behavior, thermoregulation and cardiovascular regulation • Numerous subtypes of receptors
  28. 28. Histamine • Recently identified as a neurotransmitter • Originates in hypothalamus and projects to all major structures in cerebrum, brain and spinal cord • Functions not well known • Blocking produces side effects, such as sedation, weight gain and hypotension.
  29. 29. Aminobutyric Acid (GABA) • Inhibitory transmitter • Pathways almost exclusive in CNS, hypothalamus, hippocampus, basal ganglia, spinal cord and cerebellum • Receptors: – GABAA – GABAB
  30. 30. Neurotransmitters • Histamine – Autonomic and neuroendocrine regulation – Blocking – causing sedation and weight gain • GABA – Control of neuronal excitement – Inhibitory • Glutamate – Excitatory • Neuropeptides
  31. 31. New Fields of Study • Psychoendocrinology • Psychoimmunology • Chronobiology • Diagnostic Approaches
  32. 32. Neurophysiologic Procedures • Electroencephalography (EEG) • Polysomnography • Others

×