Exam 1 Pathophysiology Notes : Modules 1, 2, & 3 ALL ANSWERS 100% CORRECT FALL-2021 SOLUTION AID GRADE A+

Chapter 2: Homeostasis, Allostasis, and Adaptive Responses to Stressors Homeostasis & Allostasis Homeostasis: Remaining stable while staying the same A state in which all systems are in balance A state of equilibrium An ideal “set point” despite alterations within the body Allostasis: Ability to successfully adapt to challenges Intricate regulatory processes orchestrated by the brain A dynamic process that maintains or re-establishes homeostasis in light of environmental and lifestyle changes Stress As A Concept Physical, chemical, or emotional factor resulting in tension of body or mind Actual physical and mental state that tension produces Real or perceived threat to homeostasis Direct consciously or indirect unconsciously sensed threat to the stability of the organism Physical, chemical, or emotional factor resulting in tension of body or mind Actual physical and mental state that tension produces Real or perceived threat to homeostasis Direct consciously or indirect unconsciously sensed threat to the stability of the organism General Adaptation Syndrome (GAS) (Selye) Three stages: Alarm, resistance/adaption, and exhaustion Alarm stage: fight-or-flight response as the result of stressful stimulus ▪ Hypothalamic-pituitary-adrenal (HPA) axis Resistance/adaptation: activity of the nervous and endocrine systems in returning the body to homeostasis ▪ Allostatic state: activity of various systems attempting to restore homeostasis Exhaustion: point where body can no longer return to homeostasis ▪ Allostatic overload: “cost” of body’s organs and tissues for an excessive or ineffectively regulated allostatic response; effect of “wear and tear” on the body Stressors Agents or conditions that can produce stress; endanger homeostasis ▪ May be external or internal • External examples: school, work, life event (wedding) • Internal examples: cancer, child birth/pregnancy ▪ Physical, chemical, biological, social, cultural or psychological • Physical: hand injury • Social: standing in front of a class • Cultural: acceptance/ability to practice ▪ Vary in scope, intensity, and duration ▪ Reactions to stress vary depending upon genetic constitution, gender, past experiences, cultural influences, developmental stage, and age • Past experience: a child afraid of a playground b/c he was previously abused there ▪ Can include both negatively and positively perceived events Risk Factors: Not stressors, but conditions or situations that increase the likelihood of encountering a stressor; there is some control over our stressors Neurohormonal Mediators of Stress & Adaption Catecholamines ▪ Play an integral role in allostasis ▪ Symphathico-adrenal system response mediates the fight or flight response ▪ Examples: Norepinephrine and epinephrine Norepinephrine ▪ Constricts blood vessels and raises blood pressure ▪ Reduces gastric secretions Epinephrine ▪ Enhances myocardial contractibility, increases heart rate, and increases cardiac output ▪ Causes bronchodilation ▪ Increase the release of glucose from the liver (glycogenolysis) and elevates blood glucose levels Adrenocortical Steroids ▪ Critical to maintenance of homeostasis ▪ May synergize or antagonize effects of catecholamines • Examples: Cortisol and aldosterone ▪ Cortisol • Primary glucocorticoid • Affects protein metabolism • Promotes appetite and food-seeking behaviors • Had anti-inflammatory effects • Too much cortisol over time can lead to pro-inflammatory effects ▪ Aldosterone (secreted by the adrenal cortex) • Primary mineralocorticoid • Promotes reabsorption of sodium and water • Increases blood pressure Endorphins and Enkephalins ▪ Endogenous opioids (body’s natural pain relievers) • Raise pain threshold • Produce sedation and euphoria; (reason athletes are able to play with injuries) Immune Cytokines ▪ Secreted by macrophages during stress response • Enhance immune system response • Prolonged stress can suppress immune functioning (makes you more susceptible to viruses) ◆ Example: Interleukin-1 Sex Hormones ▪ Affect stress responses, thus influencing allostasis ▪ May help gender responses during stress • Examples: Estrogen, testosterone, and dehydroepiandrosterone Other Hormones: ▪ Growth hormone- can increase during stress to enhance immune function ▪ Prolactin: similar to structure of growth hormone; role in immune response ▪ Oxytocin: produced during childbirth and lactation; associated w/bonding and social attachment; though to moderate stress response and produce a calming effect Adaption, Coping, & Illness Individual stress responses: change with time and circumstances Effects of stress response is influenced by: ▪ Genetics ▪ Socioeconomic status ▪ Prior susceptibilities ▪ Preexisting health status ▪ Allostatic state ▪ Ability to manage stress Adaption: biopsychosocial process of change in response to new or altered circumstances, internal or external in origin Coping: behavioral adaptive response to a stressor using culturally based coping mechanisms Adaption and coping: terms used interchangeable Distress: perceived inability to cope with a stressor Adaption methods for stress: habitation and desensitization (biofeedback, visualization, and meditation) Allostatic overload: inadequate adaption mechanisms or excessive allostatic load; results in inability to maintain homeostasis Leads to various illness and disorders, both physical & emotional Chemical mediators from the stress response contribute to various illnesses: cortisol, catecholamines, and cytokines Module 1 Chapter 3: Cell Structure & Function Plasma Membrane Membrane Structure All cells enclosed by a barrier composed primarily of protein and lipid Highly selective filter than shields internal cell context from external environment Plasma Membrane’s Functions Transport nutrients & waste products Generate membrane potentials Cell recognition & communication Growth regulation Sensor of signals that enable cell to respond & adapt to changes in environment Lipid Bilayer Related to special properties of lipid molecules that cause them to arrange in bilayers 3 types of membrane lipids: Cholesterol, phospholipids, glycolipids All 3 types are amphipathic (able to form bilayers in aqueous solutions) ▪ Hydrophilic: water loving ▪ Hydrophobic: water fearing Membrane Proteins Approximately 50% of typical cell membranes mass: protein Type of membrane protein in cell depends on cell’s primary functions Type of protein varies with cell type and environmental conditions ▪ Transmembrane proteins extend across bilayer & have contact with interal and external environments ▪ Functions • Transport charged & polar molecules in & out of cells • Transduction of extracellular signals into intracellular messages Some membrane proteins need tight junctions ▪ Act like a fence to confine some proteins ▪ Connect neighboring cells Organization of Cellular Compartments Cytoskeleton Organized protein network that prevents eukaryotic cell’s organelles from free floating Functions: ▪ Maintains cell’s shape