Akeo Wk 1 FEAB Stress

Chapter 10: Stress and Disease

Stress

• Defined as a perceived or anticipated threat that disrupts a person's well-being or homeostasis.

• Can be physical (e.g., cold temperatures, moving heavy equipment) or psychological (e.g., pressure to meet deadlines, juggling multiple job assignments).

Traditional Overview of Stress

• Walter B. Cannon (Physiologist): Introduced the concept of "Fight or Flight Response."

• Hans Selye (Endocrinologist): Introduced

  • Physiological stress effects:

    • Enlargement of the adrenal gland.

    • Decreased lymphocyte levels.

    • Development of bleeding ulcers.

  • Developed the General Adaptation Syndrome (GAS), explaining that physiological stress impairs the ability to resist future stressors.

General Adaptation Syndrome (GAS)

• Three Stages:

  • Alarm Stage:

    • Hormones and catecholamines are secreted for emergency preparation.

    • Body's defenses are activated.

  • Resistance/Adaptation Stage:

    • Mobilization of bodily resources for sustained challenges.

    • Symptoms may include irritability, frustration, and poor concentration.

  • Exhaustion Stage (Allostatic overload):

    • Occurs if stress continues and adaptation fails.

    • Can lead to stress-related disorders (e.g., fatigue, depression, anxiety, burnout).

The Alarm Reaction

• Involves the hypothalamus and hormonal response:

  • Hypothalamus ➔ Anterior pituitary ➔ ACTH ➔ Adrenal cortex ➔ Cortisol and adrenaline secretion.

Allostasis

• Concept known as "Stability through change."

• The brain continuously monitors future events and anticipates necessary adaptations from neuroendocrine and autonomic systems.

• Allostatic overload: Overactivation of adaptive systems that may lead to disease, varies from individual to individual.

Hypothalamic-Pituitary-Adrenal (HPA) Axis

• Steps:

  • Hypothalamus secretes corticotropin-releasing hormone (CRH).

  • Pituitary gland releases adrenocorticotropic hormone (ACTH).

  • Adrenal glands secrete cortisol, aldosterone, and adrenaline.

Neuroendocrine Regulation

• Involvement of the central nervous system, sympathetic nervous system, and various hormones (e.g., epinephrine, norepinephrine, cortisol).

• Physiological responses include increased blood pressure, bronchodilation, and changes in cardiac output.

Cortisol Effects

• Secreted during stress; regulates:

  • Arousal, cognition, mood, sleep, metabolism, cardiovascular tone, and growth/reproduction.

  • Stimulates gluconeogenesis and elevates blood glucose levels.

  • Acts as a powerful anti-inflammatory and immunosuppressive agent.

• Chronic Elevation Effects:

  • Includes obesity, sleep deprivation, hypertension, diabetes, cognitive impairments, and gastric ulcers.

Sympathetic Nervous System

• Activation triggers rapid catecholamine release:

  • Major hormones released: norepinephrine and epinephrine.

• Parasympathetic nervous system: Helps to balance the effects of the SNS, promoting rest and digestion.

Catecholamines

• Function in regulating cardiovascular, pulmonary, hepatic, and immune systems.

• Stimulate two receptor types: α-adrenergic and β-adrenergic.

• Chronic release can lead to health issues like myocardial infarction and stroke.

Role of the Immune System

• Immune cells have stress response receptors; stress affects immune function.

• Chronic stress may lead to immune dysregulation and chronic inflammatory diseases (e.g., cardiovascular disease, diabetes).

Effects of Early-Life Stress

• Early chronic stress impacts brain development, increasing disease risk.

• Prenatal stress can lead to spontaneous abortions and fetal malformations.

Effects of Stress on Telomeres

• Telomeres protect chromosomes, shorten with aging, and are affected by stress.

• Stress accelerates shortening, increasing early death risk, but lengthening can occur through exercise and stress management.

Coping and Intervention Strategies

• Coping: Managing stress may be adaptive (healthy) or maladaptive (harmful).

  • Effective strategies include seeking social support and problem-focused approaches.

Effects of Exercise

• Exercise provides numerous benefits:

  • Reduces inflammation, improves cognitive function, and helps prevent obesity.

Mindfulness Therapy

• Involves monitoring experiences with acceptance, shown to be effective in modulating stress effects.

Stress Response Assessment Questions

• Example: Physiological effects of catecholamines include increased heart rate, bronchodilation, and increased blood pressure.

• Adaptive coping example: Seeking social support is beneficial.

Chapter 5: Fluids and Electrolytes, Acids and Bases

• Will continue in the next section, providing insight into bodily fluid distribution and electrolyte balance.