Chapter 4_2 flashcards
(43 cards)
General Adaptation Syndrome (GAS) - Hans Selye: Stage 1 - Alarm Stage
Initiated by activation of the sympathetic nervous system (SNS)[cite: 1]. State of arousal with CNS, SNS, and adrenal gland stimulation. [Text] Release of norepinephrine and epinephrine. [Text] [cite: 2] Increased heart rate, alertness, blood pressure. [Text] [cite: 2] Hypothalamus releases CRF -> anterior pituitary secretes ACTH -> adrenal cortex secretes cortisol. [Text] Adrenal medulla secretes epinephrine & aldosterone. Posterior pituitary secretes ADH. [Text]
Alarm Stage: Role of Norepinephrine
Released by SNS; increases alertness, stimulates cardiorespiratory/vascular responses (vasoconstriction to heart/lungs/muscles, increased HR/RR, decreased peripheral circulation, pupil/bronchiole dilation, slowed GI/GU activity). [Text]
Alarm Stage: Role of Cortisol
Raises blood glucose, enhances muscle strength, potentiates sympathetic activity. Mobilizes glucose, amino acids, fat for energy. Initially increases WBC response/counteracts inflammation (3-5 days); prolonged secretion causes immunosuppression. [Text]
Alarm Stage: Role of Epinephrine & Aldosterone
Epinephrine (adrenal medulla): Potentiates sympathetic reaction. Aldosterone (adrenal cortex, stimulated by ACTH & Angiotensin II indirectly): Increases Na+ and water reabsorption at kidney nephrons. [Text]
Alarm Stage: Role of Antidiuretic Hormone (ADH)/Vasopressin
Secreted by posterior pituitary; enhances water reabsorption from kidney nephrons into bloodstream. Contributes to increased blood pressure and volume. [Text]
General Adaptation Syndrome (GAS) - Hans Selye: Stage 2 - Resistance Stage
Body attempts to adapt, stave off stress effects, and maintain homeostasis [cite: 3] through continual hormone and catecholamine secretion. [Text] If stress subsides, PSNS responses resume (relaxation). [Text] Involves hormonal support (e.g., cortisol). [Text] [cite: 3]
General Adaptation Syndrome (GAS) - Hans Selye: Stage 3 - Exhaustion Stage
Occurs when stress is prolonged and resources are depleted[cite: 4]. Stress overwhelms body’s ability to defend. Body’s resources depleted, signs of systemic dysfunction occur (run-down, unable to cope, depressed, anxious, physically ill). [Text] Leads to systemic dysfunction. [Text] [cite: 4] Causes immunosuppression (prolonged cortisol, thymus atrophy, decreased T lymphocytes). [Text]
McEwen’s Stress Theory: Allostasis vs. Homeostasis
Allostasis: A dynamic state of balance that changes according to exposure to stressors, creating new physiological set points. Homeostasis: A set state of balance with strict, unchanging parameters or set points. [Text]
McEwen’s Stress Theory: Four Mechanisms of Allostatic Load Accumulation
- Repeated stressful experiences (multiple stresses consecutively/simultaneously). 2. Inability of the individual to adapt to stress (fewer coping mechanisms, insufficient social support). 3. Prolonged reaction to a stressor (stress reaction doesn’t shut down timely). 4. Inadequate response to a stressor (faulty stress response, imbalanced neuroendocrine activity). [Text]
McEwen’s Stress Theory: Allostatic Overload
Occurs when stress exceeds the body’s ability to adapt, initiating pathophysiological disorders. Influenced by individual’s adaptive ability (genetics, lifestyle, support, etc.). [Text]
Medications & Mental Health: Antidepressants Therapeutic Levels
Antidepressants typically take 2–3 weeks to reach therapeutic blood levels and exert their full effect. [Text] [cite: 6]
Medications & Mental Health: Nurse’s Role in Regimen Changes
Nurses cannot alter medication regimens (increase dose, discontinue, or switch drugs)—only a licensed prescriber can make these changes. [Text] [cite: 7]
Effects of Immobility: Venous Stasis & DVT
Stagnation of venous blood in lower extremities due to lack of muscle contraction and supine position. [Text] Can lead to deep vein thrombosis (DVT). [Text] [cite: 8]
Effects of Immobility: Pulmonary Embolism (PE) Risk
Venous clot (DVT) from leg can travel to inferior vena cava -> right heart -> pulmonary artery, lodging as a PE, blocking lung perfusion. [Text]
Effects of Immobility: Skin Breakdown & Pressure Injuries
Constant pressure over bony prominences (occiput, shoulders, elbows, sacrum, ankles, heels) impairs blood flow, leading to tissue ischemia and pressure injuries. [Text] Risk of pressure injuries; assess skin frequently and reposition every 2 hours. [Text] [cite: 9]
Pressure Injury Stages
Stage I: Persistent redness/irritation. Stage II: Loss of skin (epidermis/dermis), ulcer/blister. Stage III: Ulceration through epidermis, dermis, subcutaneous tissue. Stage IV: Full thickness loss to fascia, muscle, bone. [Text]
Effects of Immobility: Contractures
Muscles shorten over inactive joints, limiting range of motion. Connective tissue also shortens/degenerates. [Text] Result from disuse atrophy. [Text] [cite: 10] Common presentation: flexed hips/knees (fetal-like)[cite: 15], flexed arms/neck[cite: 15].
Effects of Immobility: Gastroesophageal Reflux (GERD) & Aspiration Pneumonia
Supine position increases susceptibility to GERD. [Text] Increases risk of aspiration pneumonia. [Text] [cite: 10] Aspiration pneumonia can occur from gastric reflux in supine clients. [Text] [cite: 13]
Effects of Immobility: Orthostatic Hypotension
Delay in arterial vasoconstriction upon standing after prolonged bedrest, causing temporary drop in BP and inadequate cerebral perfusion. Symptoms: dizziness, tachycardia, diaphoresis, syncope. [Text] [cite: 11]
Effects of Immobility: Pulmonary System Changes
Diminished lung expansion, decreased cough strength, atelectasis (alveolar collapse), hypoxemia, pooled secretions (pneumonia risk). [Text]
Effects of Immobility: Musculoskeletal System Changes (Muscle)
Disuse atrophy (muscles decrease in size), muscle weakness, shortening of muscle length. [Text]
Effects of Immobility: Musculoskeletal System Changes (Bone)
Lack of weight-bearing -> osteoclastic activity > osteoblastic activity -> bone demineralization (osteoporosis), especially in trabecular bone (hip, wrist, vertebrae). Increased risk of pathological fractures. Increased urinary calcium -> kidney stone risk. [Text]
Effects of Immobility: Renal & Urological System Changes
Supine position hinders urine drainage -> urinary stasis -> increased risk of UTI and kidney stones (due to increased urinary calcium from bone demineralization). [Text]
Effects of Immobility: Gastrointestinal System Changes
Diminished peristalsis, decreased intestinal absorption, constipation (due to slowed peristalsis, muscle atrophy needed for defecation). [Text]
