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CredibleWaterfall4552

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Beal University

Tobi Ajayi

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stress response nervous system cortisol physiology

Summary

This document discusses stress and coping mechanisms, distinguishing between the central and peripheral nervous systems and comparing the sympathetic and parasympathetic nervous systems. It also explores drug use in modifying autonomic nervous system functions, the three phases of stress response, the role of cortisol, and behavioral/emotional responses to stress.

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Tobi Ajayi Stress and Coping Distinguish between functions of the central and peripheral Learning outcomes nervous system. Compare and contrast the actions of the sympathetic and parasympathetic nervous systems, and the...

Tobi Ajayi Stress and Coping Distinguish between functions of the central and peripheral Learning outcomes nervous system. Compare and contrast the actions of the sympathetic and parasympathetic nervous systems, and their physiological effects. Discuss how drugs are used to modify functions of the autonomic nervous system. Understand the 3 phases of stress response, as well as the role of Cortisol and the Hypothalamus-Pituitary-Adrenal Axis. Understand the behavioral and emotional responses to stress, and associated areas of the brain. Stress What is Stress? Any physical (e.g. injury or illness)or psychological stimuli (e.g. fear or anxiety) that disrupts homeostasis. Acute stress: results from immediate stressors. (e.g. increased heart rate). This type of stress is adaptive, helping the body Stress Response & Adaptation fight, cope with, or flee from stressor. The body responds to stressors by Chronic stress: occurs when the stressor producing actions to maintain persists over an extended period. Prolonged homeostasis. exposure to chronic stress is maladaptive, Alarm Stage and can lead to cumulative physiological and Resistance Stage psychological effects. Exhaustion stage. Central Nervous System Consists of Brain & Spinal Cords. review of nervous system Process and integrate information about environmental changes Receives and processes information from PNS. Plans and initiates response or action. Peripheral Nervous System Consists of Cranial nerves & Spinal nerves. Recognizes changes in the internal and external environment. Sensory neurons = Messages to the CNS. Motor neurons = Messages from the CNS to carry out responses. Motor =Somatic component (voluntary) or Autonomic component (involuntary) Sensory Neurons Specialized receptors and nerves that recognize Neurons of pns changes in the environment and coverts Touch Pain Heat Body position Light Sound Composition of body fluids Motor Neurons Respond to changes by contracting muscles or secreting chemicals. Somatic nervous system: voluntary control over skeletal muscles Autonomic nervous system: involuntary control over vital functions of the cardiovascular, digestive, respiratory, and genitourinary systems. structures of the autonomic nervous system Sympathetic NS: Flight or Flight. Parasympathetic NS: Rest and Digest. Most organs and glands receive inputs from the 2 branches of the ANS They have opposing functions, therefore the activity of organs/glands depend on which branch’s signal is more active. Homeostasis is achieved by changing tone of one or both branches. Tone is altered by: -Increasing or decreasing the firing of sympathetic/parasympathetic nerves structures of the autonomic nervous system effects of the autonomic nervous system Target Tissue Sympathetic Parasympathetic Brain Increases alertness Pupil Dilates Constricts Salivary glands Decreases secretion Increases secretion Heart Increases HR, contractility Decreases HR Lungs Dilates bronchi, increases RR Constricts bronchi, decreases RR GI Decreases motility and secretions Increases motility and secretions Pancreas Increases release of glucagon Increases secretion of insulin Adrenal Increases epinephrine secretion medulla Relaxes bladder muscles, decreases urine Urinary Contracts bladder muscles, Increases production urine production Sex Inhibits Stimulates Organs Integumentary Increases perspiration synaptic transmission Neurons communicate through synapses. Pre-synaptic Neuron initiates signal that is received by the post-synaptic Neuron. Presynaptic neurons (originating inside of CNS) contain neurotransmitters (stored in vesicles) that are released into the synaptic cleft when stimulated by action potential. Binding of neurotransmitters to receptors on post-synaptic neuron (outside CNS) or target tissues at neuroeffector junction induces response (activate or inhibit AP) synaptic tranmission Over 50 neurotransmitter in the body! Norepinephrine and Acetylcholine are the main neurotransmitters of the Autonomic nervous system. synaptic transmission Termination of the neurotransmitter action Neurotransmitter separates from receptor, returning it to baseline activity Neurotransmitter is removed from synapse through: * Reuptake back into presynaptic neuron * Degradation in synaptic cleft by enzymes -Acetylcholine degraded by acetylcholinesterase (AchE) –Norepinephrine degraded by Monoamine Oxidase (MAO) or catechol-o-methyl transferase (COMT) in synapse Autonomic Nervous System Drugs Alter synthesis of the neurotransmitter in the preganglionic nerve. Prevent storage of the neurotransmitter in vesicles within the preganglionic nerve. Influence release of the neurotransmitter from the preganglionic nerve. Bind to the neurotransmitter receptor site on the postganglionic nerve. Prevent the normal destruction or reuptake of the neurotransmitter. ANS Receptors Cholinergic Receptors (Respond to Ach) Nicotinic –Found on postganglionic neurons in ANS *Promotes sympathetic and parasympathetic Adrenergic Receptors effects –Found at neuromuscular junction of skeletal (Responds to Epinephrine and muscle cells. Epinephrine) Alpha and Beta subtypes Muscarinic –Found on target tissues of sympathetic –Found on parasympathetic target tissues *Promotes parasympathetic effects nervous system *Promotes sympathetic effects ANS Receptors ANS Receptors Receptor Selected Effects Neurotransmitter Receptor Location Postganglionic neurons in both SNS Mix of sympathetic and parasympathetic Ach Nicotinic and PNS effects Constricts pupils, decreases HR, constricts Muscarinic Target tissues in PNS bronchi, increases GI motility and secretions NE Alpha- 1 Target tissues in SNS Constricts arterioles, dilates pupils Alpha- 2 Decreases tone of SNS Beta- 1 Increases HR and force of contraction of heart Dilates bronchi, dilates arterioles to skeletal Beta- 2 muscles Overview of nervous system regulation of autonomic function. Higher Brain Centers Autonomic functions can be modified by higher brain centers. The hypothalamus can link emotional states from the limbic system to physiological responses (e.g. rage = increased HR & RR, depression = decrease in BP). By reducing anxiety and promoting relaxation, anxiolytics (e.g. benzodiazepines) may indirectly modulate activity of the hypothalamic-pituitary-adrenal (HPA), reducing sympathetic nervous system activation. stress response Resistance/Adaptation Alarm Reaction Persistent stress activates the Hypothalamus-Pituitary- Stressor = Activation of sympathetic NS (Fight Adrenal(HPA) axis which promotes the secretion of or Flight). adrenocorticotropic hormone (ACTH) by stimulates pituitary gland. ACTH stimulates adrenal cortex to make Cortisol. SNS = Norepinephrine and Epinephrine released (from adrenal medulla) Cortisol helps the body deal with long-term stress by Result in increased Symapthetic NS functions increasing blood sugar, enhancing metabolism, and suppressing non-essential functions like digestion and and decrease in parasympathetic innervation immune response. Exhaustion HPA axis may become dysregulated Sustained elevation of BP and HR may lead to cardiovascular diseases. Prolonged inhibition of digestive & urinary functions = gastrointestinal and renal disorders. Chronic stress weakens the immune system. Decreased muscle mass and fat = Weight loss cortisol “Stress Hormone” Helps body deal with stress by increasing energy supply Liver: promotes metabolism of glycogen to glucose. Muscle: reduces glucose uptake/consumption, and promotes breakdown of muscle proteins into amino acids to produce energy. Fat cell: promotes lipid breakdown for additional energy. Pancreas: decreases insulin and increases glucagon to increase blood glucose. Others: -Increases BP by increasing promoting vasoconstriction. -Reduces inflammation and suppresses immune system behavioural and emotional responses to stress Hippocampus and Prefrontal cortex are the 2 areas of the brain with the most glucocorticoid receptors, therefore they are highly sensitive to Cortisol. Both areas atrophy with longterm stress. *Hippocampus: associated with learning and memory. *Prefrontal cortex: responsible for impulse control, judgment, planning, and reasoning. Amygdala: processes emotions, particularly fear and pleasure, and plays a crucial role in the formation of emotional memories. Long-term stress can lead to structural and functional changes in the amygdala, resulting in heightened emotional sensitivity, increased anxiety and fear responses, and an overall greater risk of developing mood disorders. Chronic stress may lead to an increase in the size of the amygdala and affect its connectivity with other brain regions involved in emotional regulation. behavioural and emotional responses to stress. Depression Addiction Learned helplessness Alcohol, tobacco, illicit drugs. Anhedonia Poor coping mechanism. May be related to the prefrontal Compounded by impairment to frontal cortex’s decreased production cortex and sensitivity to serotonin with prolonged stress. Anxiety Fear = “Flight” in fight. Chronic stress can lead to changes in Anger how memories are formed and Stress initaites fight or flight recalled in the amygdala, often reponse, and anger naturally heightening the recollection of ccompanies the “fight” negative experiences. Coping with Stress Perceived control Optimism Social Support Managing Stress Exercise Coping with stress Mindfulness and Meditation Cognitive flexibility Faith Professional help. nursing considerations When addressing stress responses in patients, nurses should consider the following: Assessment: Regularly assess the patient’s stress levels, coping mechanisms, and emotional state using standardized tools or open- ended questions. Education: Provide education about stress management techniques, such as deep breathing exercises, mindfulness, and relaxation techniques. Supportive Environment: Create a calm and supportive environment to help reduce anxiety and promote relaxation. Encourage Communication: Foster open communication, allowing patients to express their feelings and concerns without judgment. Holistic Approach: Consider the patient's physical, emotional, social, and spiritual needs in developing care plans. Promote Healthy Lifestyle: Encourage regular exercise, balanced nutrition, and adequate sleep, which can help mitigate stress effects. Involve Family: Engage family members in care discussions and stress management strategies to provide additional support. Monitor for Symptoms: Be vigilant for signs of chronic stress or anxiety, such as changes in appetite, sleep disturbances, or withdrawal from social activities. Referral: When necessary, refer patients to mental health professionals for further support or therapy. Self-Care: Model and encourage self-care practices for both patients and nursing staff to prevent burnout and improve overall well- being.

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