Biological Implications in Psychiatric Mental Health Nursing

Introduction

• Recent emphasis on studying biological foundations of:

  • Cognitive processes

  • Emotional processes

  • Behavioral processes

• This study area is called psychobiology.

A Review of the Nervous System

The Brain

• Divided into three main regions:

  • Forebrain

  • Cerebrum

    • Largest part of the brain

    • Comprises right and left hemispheres separated by the corpus callosum

    • Each hemisphere contains:

    • Frontal lobe

    • Parietal lobe

    • Temporal lobe

    • Occipital lobe

  • Diencephalon

    • Connects cerebrum with lower brain structures

    • Contains thalamus and hypothalamus, part of the limbic system.

  • Midbrain

  • Also known as mesencephalon

  • Extends from the pons to the hypothalamus

  • Responsible for integration of visual, auditory, and righting reflexes

  • Hindbrain

  • Composed of:

    • Pons

    • Part of the brainstem

    • Centers for respiration and associated with sleep

    • Medulla

    • Connects the spinal cord and pons

    • Controls heart rate, respiration, and reflexes such as sneezing

    • Cerebellum

    • Connects to the brainstem via fiber tracts

    • Involved in involuntary movement

Clicker Question 1

• Question: A nursing student is learning about the human limbic system. Which statement demonstrates effective teaching?

  • A) "The limbic system helps stabilize emotional behavior."

  • B) "The limbic system functions to assist with symbolic thinking."

  • C) "The limbic system aids in analytical thinking."

  • D) "The limbic system helps modulate motor coordination."

Answer to Clicker Question 1

• Correct Answer: A

  • Explanation: The limbic system is often referred to as the "emotional brain" and is primarily involved in stabilizing emotional behavior.

Neurons

• Composition:

  • Cell body

  • Axons

  • Dendrites

• Classes of neurons:

  • Afferent neurons

  • Efferent neurons

  • Interneurons

The Autonomic Nervous System

Divisions

• Sympathetic division

  • Dominant during stressful situations

• Parasympathetic division

  • Dominant during relaxed situations

Autonomic Nervous System Functions

Parasympathetic Effects

• Stimulates secretion of saliva

• Slows heartbeat

• Constricts bronchi

• Stimulates peristalsis and secretion

• Stimulates release of bile

• Contracts bladder

Sympathetic Effects

• Dilates pupils

• Inhibits saliva flow

• Accelerates heartbeat

• Dilates bronchi

• Inhibits peristalsis and secretion

• Converts glycogen to glucose

• Secretion of adrenaline and noradrenaline

• Inhibits bladder contraction

Clicker Question 2

• Question: A client diagnosed with panic-level anxiety. Which biological system is responsible?

  • A) Parasympathetic system

  • B) Sympathetic system

  • C) The cerebral cortex

  • D) The cerebellum

Answer to Clicker Question 2

• Correct Answer: B

  • Explanation: The sympathetic division of the autonomic nervous system is dominant during stress, preparing the body for a "fight or flight" response, thus relating to the client's panic anxiety symptoms.

Neurotransmitters

• Cholinergics:

  • Acetylcholine

• Monoamines:

  • Norepinephrine

  • Dopamine

  • Serotonin

  • Histamine

• Amino Acids:

  • Inhibitory amino acids

  • Excitatory amino acids

• Neuropeptides:

  • Opioid peptides

  • Substance P

  • Somatostatin

The Neuroendocrine System

• Definition: Neuroendocrinology studies the interactions between the nervous system and the endocrine system, examining how hormones affect cognitive, emotional, and behavioral functioning.

The Pituitary Gland

Posterior Pituitary

• Hormones produced:

  • Antidiuretic hormone

  • Oxytocin

Anterior Pituitary

• Hormones produced:

  • Growth hormone

  • Thyroid-stimulating hormone

  • Adrenocorticotropic hormone

  • Prolactin

  • Gonadotropic hormones

  • Melanocyte-stimulating hormone

Circadian Rhythms

• Follow a near 24-hour cycle

• Might influence various regulatory functions

• Potential role in psychopathology

Genetics

• Genetics: Study of biological transmission of traits (physical and/or behavioral) from parents to offspring.

  • Genotype: Genetic constitution of an individual

  • Phenotype: Observable characteristics or traits

Genetic Contributions to Psychiatric Disorders

• Studies have determined both genetic and environmental contributions to psychiatric disorders

• Identification of potential genetic links to various psychological disorders

Psychoneuroimmunology

• Definition: Psychoneuroimmunology studies the relationship between the immune system, nervous system, and psychological processes.

• Research has investigated implications of the immune system in psychiatric illnesses.

Components of the Immune Response

• Normal Immune Response:

  • Nonspecific immune reactions

  • Specific immune mechanisms

  • Cytokines

Implications of the Immune System in Psychiatric Illness

• Increased susceptibility to illness following exposure to stressful stimuli

• Effects of hormones and neurotransmitters on immune response

Psychopharmacology and the Brain

• Emphasizes the need for understanding biological mechanisms of psychoactive drugs

• While nonmedical treatments exist, psychopharmacology remains a primary intervention for mental disorders

Implications for Nursing

• Shift from psychosocial to biopsychosocial focus in psychiatric nursing

• Integration of new science and technology into practice, education, and research

Specialized Knowledge Required for Psychiatric Nurses

• Understanding of:

  • Neuroanatomy and neurophysiology

  • Neuronal processes

  • Neuroendocrinology

  • Circadian rhythms

  • Genetic influences

  • Psychoneuroimmunology (PNI)

  • Trauma

  • Psychopharmacology

  • Diagnostic technology