Mental Health Chapter 2 PDF

Chapter 2 Biological Implications Copyright ©2023 F.A. Davis Company Introduction § Recently, a greater emphasis has been placed on the study of the biological foundations of Cognitive processes Emotional processes Behavioral processes § This area of study is called psychobiology. Copyright ©2023 F....

Chapter 2 Biological Implications Copyright ©2023 F.A. Davis Company Introduction § Recently, a greater emphasis has been placed on the study of the biological foundations of Cognitive processes Emotional processes Behavioral processes § This area of study is called psychobiology. Copyright ©2023 F.A. Davis Company A Review of the Nervous System § The Brain Forebrain ‒ Cerebrum ‒ Diencephalon Midbrain ‒ Mesencephalon Hindbrain ‒ Pons ‒ Medulla ‒ Cerebellum Copyright ©2023 F.A. Davis Company A Review of the Nervous System (continued_1) § The forebrain consists of the cerebrum and the diencephalon. Cerebrum ‒ It is the largest part of the brain. ‒ It consists of right and left hemispheres separated by corpus callosum. ‒ Each hemisphere contains frontal, parietal, temporal, and occipital lobes. Copyright ©2023 F.A. Davis Company Cerebrum: forebrain § The cerebrum consists of a right and left hemisphere, connected by a deep groove, which houses a band of 200 million neurons (nerve cells). This is called the corpus callosum. The surface of the cerebrum consists of gray matter and is called the cerebral cortex. These gray matter cell bodies are thought to be the actual thinking structures of the brain. Another pair of masses of gray matter called basal ganglia is found deep within the cerebral hemispheres. They are responsible for certain subconscious aspects of voluntary movement, such as swinging the arms when walking. Each hemisphere of the cerebral cortex is divided into the frontal lobe, parietal lobe, temporal lobe, and occipital lobe. Frontal Lobes: Control voluntary body movement through impulses and may also play a role in emotional experiences. Parietal Lobes: Manage sensory input including touch, pain, taste, etc. Temporal Lobes: Manage auditory functions and smell and play a role in the expression of emotions. Occipital Lobes: Primary area of visual reception and interpretation. Copyright ©2023 F.A. Davis Company Diencephalon: forebrain § The diencephalon connects the cerebrum with lower structures of the brain. The major components of the diencephalon include the thalamus and the hypothalamus, which are part of a neuroanatomical loop of structures known as the limbic system. Thalamus: Integrates sensory input (except smell) to help interpret the whole picture. Also helps block minor sensations. Hypothalamus: Regulates the pituitary gland, visceral responses during emotional states, appetite, temperature, blood pressure, thirst, and circadian rhythms. Limbic System: Includes the thalamus and hypothalamus as well as other minor structures. Called the “emotional brain,” it is associated with feelings of fear and anxiety; anger, rage, and aggression; love, joy, and hope; and with sexuality and social behavior. Copyright ©2023 F.A. Davis Company A Review of the Nervous System (continued_2) § The forebrain consists of the cerebrum and the diencephalon. Diencephalon ‒ Connects cerebrum with lower structures of the brain ‒ Consists of thalamus and hypothalamus, which are part of a loop of structures known as the limbic system Copyright ©2023 F.A. Davis Company Practice Question 1. A nursing student is learning about the human limbic system. Which student statement demonstrates that teaching about the function of the limbic system has been effective? 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.” Copyright ©2023 F.A. Davis Company Practice Answer Correct Answer: A The limbic system is the “emotional brain” and can help in stabilizing emotional behavior. Copyright ©2023 F.A. Davis Company Mesencephalon § The mesencephalon is located in the midbrain. Extends from the pons to the hypothalamus Responsible for integration of visual, auditory, and righting reflexes § The mesencephalon is responsible for integration of various reflexes: Visual reflexes: automatically turning away from a dangerous object when it comes into view Auditory reflexes: automatically turning toward a sound that is heard Righting reflexes: automatically keeping the head upright and maintaining balance Copyright ©2023 F.A. Davis Company Hindbrain § The hindbrain consists of the pons, medulla, and cerebellum. § Pons Part of the brainstem that transmits messages between parts of the nervous system Contains centers for respiration and is associated with sleep Copyright ©2023 F.A. Davis Company Hindbrain (continued) § Medulla Connects the spinal cord and pons Responsible for heart rate, respiration, and reflexes like sneezing swallowing, sneezing, coughing, and vomiting. § Cerebellum Connects to the brainstem through bundles of fiber tracts Concerned with involuntary movement Copyright ©2023 F.A. Davis Company Neurons § Neurons are composed of Cell body: contains the nucleus of the neuron Axons: transmit impulses away from the cell body Dendrites: transmit impulses toward the cell body § Classes of neurons Afferent: carry impulses from receptors in the periphery to the CNS where they are interpreted into various sensations Efferent: carry impulses from the CNS to the periphery such as muscles that respond by contracting Interneurons: make up 99% of all nerve cells. Carry sensory or motor impulses or serve as pathways between afferent and efferent neurons. Account for thinking, feeling, learning, language, and memory. Copyright ©2023 F.A. Davis Company The Nervous System: Review § Synapse: the junction between two neurons. The small space between the axon terminals of one neuron and the cell body or dendrites of another is called the synaptic cleft. § Neurotransmitters: chemical stored in the axon terminal of neurons. An electrical impulse causes the release of neurotransmitters into the synaptic cleft. The neurotransmitter is diffused and combines with receptor sites in the postsynaptic neuron. This combination determines whether another impulse is generated, or if the transmission is terminated. Copyright ©2023 F.A. Davis Company Autonomic Nervous System § The sympathetic division Dominant in stressful situations § The parasympathetic division Dominant in relaxed situations Copyright ©2023 F.A. Davis Company Autonomic Nervous System (continued) Copyright ©2023 F.A. Davis Company Practice Question 2. A client is brought to the emergency department and diagnosed with a panic level of anxiety. What biological system domination would be responsible for this diagnosis? A. Parasympathetic system B. Sympathetic system C. The cerebral cortex D. The cerebellum Copyright ©2023 F.A. Davis Company Practice Answer Correct Answer: B The sympathetic division of the autonomic nervous system is dominant in stressful situations and prepares the body for “fight or flight.” In the situation presented, the client is experiencing panic anxiety; therefore, the sympathetic system dominates. Copyright ©2023 F.A. Davis Company Neurotransmitters Cholinergic § Cholinergics Acetylcholine: Significant in the transmission that occurs at the junctions of nerves and muscles. Functions include sleep, arousal, pain, perception, coordination of movement, and memory retention. May have some role in disorders of motor behavior and memory such as Parkinson’s and Alzheimer’s diseases. Copyright ©2023 F.A. Davis Company Neurotransmitters monoamines § Monoamines Norepinephrine: Produces activity at the postsynaptic nerve terminals in the autonomic nervous system, resulting in fight or flight. Functions include regulation of mood, cognition, perception, cardiovascular functioning, and sleep. Implicated in mood disorders such as depression and mania, anxiety states, and schizophrenia. Dopamine: Functions include regulation of movements and coordination, emotions, and voluntary decision-making ability. Increased levels are associated with mania and schizophrenia. serotonin: May play a role in sleep and arousal, libido, appetite, mood, aggression, and pain perception. Implicated in certain psychopathological conditions including anxiety states, mood disorders, and schizophrenia. Histamine: Plays a role in medicating allergic and inflammatory reactions and is associated with sustaining wakefulness. Some data suggest a role in depressive illness. Copyright ©2023 F.A. Davis Company Neurotransmitters Amino acid § Amino Acids Inhibitory amino acids: Includes gamma-aminobutyric acid (GABA) and glycine. Prevents postsynaptic excitation, interrupting the progression of electrical impulse at the synaptic junction. GABA has been implicated in anxiety disorders, movement disorders, and forms of epilepsy. Glycine has been implicated in certain types of spastic disorders. excitatory amino acids: : Includes glutamate and aspartate. Function in the relay of sensory information and regulation of motor and spinal reflexes. Implicated in the etiology of certain neurodegenerative disorders, such as Huntington’s disease, temporal lobe epilepsy, and spinal cerebellar degeneration. Copyright ©2023 F.A. Davis Company Neurotransmitters Neuropeptides § Neuropeptides Opioid peptides: Thought to have a role in pain modulation. May have some implication in schizophrenia. substance P: Plays a role in sensory transmission and regulation of pain. Elevated levels are found in cerebral spinal fluid of people with depression and post-traumatic stress disorder. Somatostatin: Acts as a neuromodulator for serotonin in the hypothalamus. High concentrations of somatostatin have been reported in brain specimens of clients with Huntington’s disease, and low concentrations in those with Alzheimer’s disease. Copyright ©2023 F.A. Davis Company The Neuroendocrine System § Neuroendocrinology is the study of the interaction between the nervous system and the endocrine system, and the effects of various hormones on cognitive, emotional, and behavioral functioning. Copyright ©2023 F.A. Davis Company Pituitary Gland § Posterior pituitary Antidiuretic hormone Oxytocin § Anterior pituitary Growth hormone Thyroid-stimulating hormone Adrenocorticotropic hormone Prolactin Gonadotropic hormones Melanocyte-stimulating hormone Copyright ©2023 F.A. Davis Company Pituitary Gland (continued) § Circadian rhythms follow a near 24-hour cycle and may influence a variety of regulatory functions. § These rhythms may play a role in psychopathology. Copyright ©2023 F.A. Davis Company Genetics § Genetics is the study of the biological transmission of certain characteristics (physical and/or behavioral) from parent to offspring. Genotype Phenotype Copyright ©2023 F.A. Davis Company Genetics (continued_1) § Studies have been conducted to determine genetic and environmental contributions to psychiatric disorders. § Possible genetic links to various psychological disorders have been discovered through these studies. Copyright ©2023 F.A. Davis Company Genetics (continued_2) § Twin studies examine the genetic vulnerability in the etiology of disorder by examining the frequency of a disorder in Monozygotic (genetically identical) twins Fraternal (nongenetically identical) twins § Twin studies examine the frequency of a disorder in genetically identical and fraternal twins. Appearance of a disorder in two genetically identical twins is strong evidence of genetic involvement. Disorders in which twin studies have suggested a possible genetic link include alcoholism, schizophrenia, major depressive disorder, bipolar disorder, anorexia nervosa, panic disorder, and obsessive-compulsive disorder. Copyright ©2023 F.A. Davis Company Genetics (continued_3) § Adoption studies allow comparisons to be made between the influences of genetics and environment. § Adoption studies show the influence of genetics versus the influence of the environment on the development of psychiatric disorders. These studies compare disorders of adopted children to those of their birth and adoptive parents. Disorders in which adoption studies have suggested a possible genetic link include alcoholism, schizophrenia, major depression, bipolar disorder, attention deficit-hyperactivity disorder, and antisocial personality disorder. Copyright ©2023 F.A. Davis Company Psychoneuroimmunology § Psychoneuroimmunology is the study of the relationship between the immune system, the nervous system, and psychological processes. § Studies have been conducted to determine the implications of the immune system in psychiatric illnesses. Copyright ©2023 F.A. Davis Company Psychoneuroimmunology Cont’d § Normal Immune Response Nonspecific immune reactions Specific immune mechanisms Cytokines § Implications of the Immune System in Psychiatric Illness Increased susceptibility following exposure to a stressful stimulus Effects of hormones and neurotransmitters Copyright ©2023 F.A. Davis Company Psychopharmacology and the Brain § Research increasingly demonstrates opportunities and benefits of nonmedical interventions for psychological illnesses. § Psychopharmacology remains a primary treatment modality for mental disorders. It is essential to understand the biological mechanisms at work in psychoactive drugs. Copyright ©2023 F.A. Davis Company function of psychotropic drugs Reuptake inhibitors drugs block reuptake of neurotransmitters, resulting in elevated levels. Drugs that inhibit catabolic enzymes promote excess buildup of the neurotransmitter at the synaptic site. Some drugs cause receptor blockade, thereby resulting in a reduction in transmission and decreased neurotransmitter activity. These drugs are called antagonists. Drugs that increase neurotransmitter activity by direct stimulation of the specific receptors are called agonists. Copyright ©2023 F.A. Davis Company Implications for Nursing § Psychiatric nursing emphasizes a smooth transition from a psychosocial approach to a biopsychosocial focus. § New science and technology must be incorporated into nursing practice, education, and research. Copyright ©2023 F.A. Davis Company Implications for Nursing (continued) § Psychiatric nurses must have a specialized knowledge about Neuroanatomy and neurophysiology: the structure and functioning of the various parts of the brain and their correlation to human behavior. Neuronal processes: the various functions of the nerve cells, including the role of neurotransmitters, receptors, synaptic activity, and informational pathways. Neuroendocrinology: the interaction of the endocrine and nervous systems, and the role that the endocrine glands and their respective hormones play in behavior. Circadian rhythms: the regulation of biochemical functioning over periods of rhythmic cycles and its influence in predicting certain behaviors. Genetic influences: the hereditary factors that predispose individuals to certain psychiatric disorders. Psychoneuroimmunology (PNI): the influence of stress on the immune system and its role in the susceptibility to illness. Psychopharmacology: the increasing use of psychotropic drugs in the treatment of mental illness. Diagnostic technology: the importance of keeping informed about the latest in technological procedures for diagnosing alterations in brain structure and function. Copyright ©2023 F.A. Davis Company