Pathophysiology Unit 2 | Chapter 6 (Porth 5th Edition) Flashcards
Homeostasis
The maintenance of a stable internal environment despite external changes, crucial for normal physiological functioning.
Constancy of the Internal Environment
A principle of homeostasis where the body regulates variables like temperature, pH, and electrolyte balance within narrow limits.
Control Systems
Biological mechanisms (e.g., nervous and endocrine systems) that monitor and adjust physiological processes to maintain homeostasis.
Negative Feedback
A regulatory mechanism where a system’s output reduces or inhibits the process, maintaining stability (e.g., insulin lowering blood glucose).
Positive Feedback
A mechanism that amplifies a response (e.g., oxytocin during childbirth), often leading to an endpoint.
Stress
A state of threatened or perceived disruption to homeostasis, triggering physiological and psychological responses.
Stress Response
The body’s adaptive reaction to stressors, involving neuroendocrine and immune system activation.
General Adaptation Syndrome (GAS)
Hans Selye’s three-stage model (alarm, resistance, exhaustion) describing the body’s response to prolonged stress.
Alarm Stage
Initial phase of GAS, characterized by fight-or-flight activation via the SAM axis and HPA axis.
Resistance Stage
Second phase of GAS, where the body attempts to adapt and restore homeostasis using sustained cortisol release.
Exhaustion Stage
Final phase of GAS, resulting in resource depletion, immune suppression, and vulnerability to disease.
Neuroendocrine Responses
Stress-induced activation of the HPA axis (cortisol) and SAM axis (adrenaline/noradrenaline).
HPA Axis
Hypothalamic-Pituitary-Adrenal axis: CRH → ACTH → cortisol release, regulating metabolism and immune function during stress.
SAM Axis
Sympathetic-Adrenal-Medullary axis: Activates the sympathetic nervous system, releasing adrenaline and noradrenaline for immediate stress response.
Cortisol
Glucocorticoid hormone released during stress; suppresses inflammation, increases blood glucose, and modulates immune function.
Catecholamines
Adrenaline and noradrenaline; enhance alertness, heart rate, and energy mobilization during acute stress.
Immune Responses to Stress
Stress alters immune function via cortisol (suppression) and cytokines (pro-inflammatory signals).
Psychoneuroimmunology
Study of interactions between psychological processes, the nervous system, and immune function during stress.
Cytokines
Signaling proteins (e.g., IL-6, TNF-α) released during stress; can promote inflammation or immune suppression.
Allostasis
The process of achieving stability through physiological or behavioral change in response to stressors.
Allostatic Load
The cumulative physiological wear and tear from chronic stress, leading to health risks (e.g., hypertension, diabetes).
Coping Mechanisms
Strategies (problem-focused or emotion-focused) to manage stress, such as planning, social support, or avoidance.
Adaptation
Successful adjustment to stress, restoring homeostasis without long-term physiological or psychological harm.
Maladaptation
Ineffective coping leading to chronic stress, dysfunction, or disorders (e.g., anxiety, cardiovascular disease).
Resilience
The ability to recover from stress, influenced by genetics, upbringing, and social support.
Acute Stress Effects
Short-term responses: increased heart rate, heightened senses, and energy mobilization via SAM axis activation.
Chronic Stress Effects
Long-term consequences: hypertension, immunosuppression, gastrointestinal issues, and mental health disorders.
Posttraumatic Stress Disorder (PTSD)
A disorder following trauma, characterized by flashbacks, hypervigilance, and emotional numbness.
Hyperarousal
PTSD symptom involving exaggerated startle response, irritability, and difficulty sleeping.
Fight-or-Flight Response
Immediate physiological reaction to threat, mediated by the SAM axis to prepare for action.
Immune Suppression
Reduced immune function due to chronic cortisol exposure, increasing infection and cancer risk.
Psychosomatic Disorders
Physical illnesses (e.g., ulcers, asthma) exacerbated or caused by psychological stress.
Cognitive Behavioral Therapy (CBT)
A treatment for stress disorders, focusing on changing maladaptive thought patterns and behaviors.
Mindfulness-Based Stress Reduction (MBSR)
Therapeutic approach using meditation and awareness to manage stress and improve adaptation.
SSRIs
Selective serotonin reuptake inhibitors; antidepressants used to treat chronic stress and PTSD by modulating serotonin levels.
Beta-Blockers
Medications (e.g., propranolol) that reduce SAM axis effects, alleviating physical symptoms of acute stress.
Social Support
A protective factor against stress, improving coping and reducing allostatic load through emotional and practical assistance.
Feedback Inhibition
Mechanism where end-products (e.g., cortisol) inhibit earlier steps in a pathway (e.g., CRH/ACTH release).
Pro-inflammatory Cytokines
Immune molecules (e.g., IL-1, IL-6) that promote inflammation, often elevated during chronic stress.
Psychogenic Stress
Stress originating from psychological sources (e.g., anxiety, trauma) rather than physical threats.
Eustress
Positive stress that enhances motivation and performance (e.g., preparing for a competition).
Distress
Negative stress causing dysfunction, often overwhelming an individual’s coping abilities.
Hypothalamus
Brain region initiating the HPA axis by releasing CRH in response to stress.
Adrenal Cortex
Produces cortisol in response to ACTH stimulation during the HPA axis activation.
Adrenal Medulla
Releases adrenaline and noradrenaline as part of the SAM axis during acute stress.
Telomeres
Protective DNA caps that shorten with chronic stress, linked to accelerated aging and disease.
Exposure Therapy
Treatment for PTSD involving gradual, controlled exposure to trauma-related stimuli to reduce fear.
Biofeedback
Technique teaching control over physiological stress responses (e.g., heart rate) through real-time monitoring.
Emotion-Focused Coping
Managing stress by regulating emotional reactions (e.g., meditation, seeking support).
Problem-Focused Coping
Addressing stressors directly through planning, problem-solving, or altering the situation.
Oxidative Stress
Cellular damage from reactive oxygen species (ROS), exacerbated by chronic stress and inflammation.
Glucocorticoid Receptors
Proteins that bind cortisol, mediating its effects on metabolism, immune function, and gene expression.
Epigenetics
Changes in gene expression (without altering DNA) due to stress, influencing vulnerability to disorders.
Vasopressin
Hormone released with CRH during stress, enhancing water retention and blood pressure.
ACTH
Adrenocorticotropic hormone; stimulates cortisol release from the adrenal cortex.
CRH
Corticotropin-releasing hormone; triggers ACTH release from the pituitary gland.
Noradrenaline
Neurotransmitter in the SAM axis, increasing alertness and redirecting blood flow during stress.
Sympathetic Nervous System
Activates fight-or-flight responses, increasing heart rate, dilating pupils, and inhibiting digestion.
Parasympathetic Nervous System
Promotes rest-and-digest functions, counterbalancing the sympathetic response post-stress.
Psychophysiological Disorders
Conditions like migraines or hypertension where stress contributes to physical symptoms.
Burnout
A state of emotional exhaustion and reduced performance due to chronic workplace stress.
Acute Stress Disorder
Short-term anxiety and dissociation following trauma, potentially progressing to PTSD if unresolved.
Hypocortisolism
Abnormally low cortisol levels, linked to chronic fatigue and fibromyalgia in some stress-related disorders.
Psychosocial Stressors
Environmental factors (e.g., poverty, discrimination) that induce stress and affect health outcomes.
Neuroplasticity
The brain’s ability to reorganize itself, influenced by stress and adaptive coping mechanisms.
Stress Inoculation
Training individuals to handle stress through gradual exposure and skill-building, enhancing resilience.
Limbic System
Brain region (including amygdala and hippocampus) involved in emotional processing and stress response regulation.
Amygdala
Detects threats and activates the HPA and SAM axes in response to perceived danger.
Hippocampus
Regulates memory formation and cortisol feedback; atrophy occurs with chronic stress.
Type A Behavior Pattern
Personality trait (competitiveness, urgency) linked to higher stress and cardiovascular risk.
Type B Behavior Pattern
Personality trait (relaxed, patient) associated with lower stress reactivity.
Telomerase
Enzyme that lengthens telomeres; reduced activity under chronic stress accelerates cellular aging.
Stress-Related Cardiomyopathy
Heart dysfunction (e.g., Takotsubo syndrome) triggered by extreme emotional stress.
Gastrointestinal Stress Effects
Symptoms like irritable bowel syndrome (IBS) or ulcers due to altered gut motility and microbiota.
Psychogenic Fever
Elevated body temperature caused by psychological stress without infection.
Adrenergic Receptors
Bind adrenaline/noradrenaline, mediating effects like increased heart rate and vasoconstriction.
Hypocretin/Orexin
Neurotransmitters regulating arousal and wakefulness, disrupted in stress-related sleep disorders.
Stress Granules
Cellular structures formed during stress to prioritize survival by halting non-essential protein synthesis.
