PATHO 370 Midterm Exam & Study Guide

Chapter 2 Homeostasis and Adaptive Responses to Stressors Homeostasis- state of equilibrium Allostasis- Ability to successfully adapt to changes Stress: a state manifested by a specific syndrome of the body developed in response to any stimuli that made an intense demand on it. Influenced by genetics, socioeconomic status, prior susceptibilities, pre-existing health status, allostatic state and ability to manage stress General Adaptation Syndrome (GAS): Involves 3 STAGES: • Alarm stage: stimulation of the SNS, resulting in release of catecholamines & cortisol • Resistance stage: body selects the most effective and economic channels of defense; cortisol levels present in first stage drop b/c they are no longer needed • Exhaustion stage: resources are depleted & signs of “wear & tear” or systemic damage appear Acute versus Chronic Stress: • Acute stress: associated with the ANS, the fight or flight response; persons with preexisting heart disease can have complications with acute stress response that can lead to arrhythmias; in healthy individuals acute stress response can redirect attention from behaviors that promote health and interrupt compliance with medication regiments & exercise programs • Chronic stress: it has been linked to health disorders including diseases of the cardiovascular, gastrointestinal, immune, & neurological systems; sympathetic activity & cortisol are elevated Physiological stress & psychosocial stress: • Physiological stress: stress-induced changes in body functions; detected by body’s normal regulatory sensors; the body alters function to restore normal balance; when normal balance is restored, negative feedback stops the reaction • Psychosocial stress: Directly affects central nervous system; turns on the stress responses, even when the body’s internal sensors have not detected an imbalance Adaptation & Coping Mechanisms: Adaptation: the ability to respond to challenges of physical or psychological homeostasis & to return to a balanced state. • Influenced by previous learning, physiologic reserve, time, genetic endowment, age, health status & nutrition, sleep-wake cycles, & psychosocial factors. Coping Mechanisms: • Guided Imagery: scene visualization • Music therapy: listening to music to ease anxiety or stress • Massage therapy: manipulation of soft tissues to promote relaxation & relief of muscle tension • Biofeedback: technique in which individual leans to control physiologic functioning Catecholamines Epinephrine: Released from the adrenal medulla. • Increases heart rate, BP and cardiac output bronchodilation. • Increases glycogenolysis and elevates blood glucose levels • Supplementation and prolongation of fight or flight response, pupil dilation, dry mouth, increased blood coagulability. Norepinephrine: Released from postganglionic fibers. • Constricts blood vessels and raises blood pressure. • Reduces gastric secretions. • Increases night and far vision Adrenal Cortical hormones Cortisol: Primary glucocorticoid, found in adrenal cortex • Alteration in glucose, fat, and protein metabolism; • Suppression of inflammatory & immune responses Aldosterone: Primary mineralocorticoid • reabsorption of sodium and water • Increases blood pressure Chapter 4 Cell Injury, Aging, and Death Cellular response to Stress/Adaptation to stress: cells may adapt by undergoing changes in size, number, and type. These changes may lead to atrophy, hypertrophy, hyperplasia, metaplasia and dysplasia. Cellular stresses also include intracellular accumulations & storage of products in abnormal amounts. Reversible Cell Injury: Hydropic swelling: water accumulation. Malfunction of Na-K pump with accumulation of Na+ within the cell. Any injury that results in loss of energy (ATP) will also result in swelling. Generalized swelling of cells in organs can lead to increase in size and weight; “megaly” Intracellular Accumulations: Excess accumulations of substances in cells. Leads to cellular injury due to: toxicity, immune response and taking up cellular space. Ex. Fatty liver Cellular changes