Psychology Chapter: Stress and Disease

Stress and Disease

• Stress is a major contributor to various illnesses, including mental health problems. Existing symptoms can also worsen due to stress.
• Severe emotional stress is linked to poor heart health outcomes.
• Stress impacts sleep, appetite, and overall physical well-being.

Chronic Stress and Brain Aging

• Long-term stress accelerates brain aging and reduces brain function, even leading to memory loss.
• Stress experienced at a young age can have lasting effects on how a person responds physiologically, psychologically, and behaviorally to stress throughout life.
• Chronic stress causes irreversible brain changes in animals.

Stressors

• Emotional: Fear, anxiety, anger
• Major Life Changes: Loss of loved one, job loss, divorce
• Trauma: Abuse, violence
• Daily Challenges: Schoolwork, work-related stress
• Relationships: Family, friends, caregiving responsibilities
• Health Concerns: Illness, injury, pain, surgery
• Sleep: Lack of sleep, insomnia
• Physical: Malnutrition, prolonged exertion
• Environment: Noise, extreme temperatures
• Substances: Medications, alcohol, drugs

Categories of Stressors

• Perception is Key: How a person perceives a situation heavily influences whether it becomes stressful.
• Acute Stressors: Temporary and short-term, often intense, with limited duration (e.g., public presentation, traffic jam).
• Chronic Stressors: Ongoing and long-term, persisting for a long period (e.g., chronic illness, financial problems, difficult relationships).
• Microstressors: Minor, everyday hassles that accumulate to contribute to stress (e.g., traffic, deadlines, unexpected tasks).

Concept of Allostatic Load

• Multiple Novel Stressors: Body encounters new, unfamiliar stressors that it cannot adapt to quickly.
• Failure to Habituate: Body cannot adjust to repeated stressors.
• Delayed Shutdown: Stress response system does not turn off when the stressor is gone.
• Inadequate Response: Body attempts inefficient compensation for weak stress response, causing constant exposure to stress hormones.
• Immune Dysregulation: Weakens immune system, increasing susceptibility to infections and diseases.
• Accelerated Disease: Underlying diseases worsen quicker.
• Brain Changes: Structures and function of the brain may alter, impacting memory, cognition, and mood.

Stress and Response

• Reactive: Immediate body reaction to a stressor (e.g., increased heart rate, muscle tension).
• Anticipatory: Body reacts as if a stressor is already happening despite it not having yet occurred.
• Conditional: Learned response triggered by specific stimuli associated with danger (often from past experience).
• Post-Traumatic Stress Disorder (PTSD): Stress response triggered by flashbacks and reminders of a past traumatic event.

Central Stress Response

• Perception in the Cortex: Cerebral cortex assesses sensory information and determines if a situation is stressful.

Relay to the Limbic System

• Information is relayed to the amygdala, hippocampus, and hypothalamus, the emotional center of the brain.

Amygdala

• Registers and processes fear. Also plays roles in other emotions, memory, and decision-making.
• Sends signals to hippocampus and hypothalamus when activated.

Hippocampus

• Primarily involved in memory processing.
• Sensitive to cortisol (stress hormone), potentially affecting memory related to the stressor.
• Stress response can be influenced by prior stressful experiences and memories.

Hypothalamic Pituitary Axis

• Receiving Information: Hypothalamus receives signals from the amygdala and hippocampus regarding stressful or painful experiences.
• Initiating the Cascade: Hypothalamus releases CRH, triggering the pituitary gland to release ACTH, stimulating adrenal glands to release cortisol (main stress hormone).

Sympathetic Nervous System Activation

• Stressors and CRH activate the sympathetic nervous system leading to the release of norepinephrine and epinephrine.

Neurotransmitters and Hormones

• Thyroid Hormone Release: Hypothalamus stimulates the pituitary gland to increase thyroid hormones (crucial for metabolism).
• ADH & Oxytocin Release: Hypothalamus releases hormones that help retain water and are associated with bonding/social connection.
  • Norepinephrine (and epinephrine): Plays a critical role in the “fight-or-flight” response, increasing brain activity and alertness.

Negative Feedback of Increased Cortisol

• Elevated Blood Sugar: Cortisol influences the liver to produce more glucose and decrease insulin sensitivity, potentially contributing to type 2 diabetes.
• Weakened Immune System: Cortisol depresses the immune system, reducing white blood cell activity and making individuals more susceptible to infections.

Loss of Tolerance

• Chronic high cortisol levels can reduce the body's tolerance for inflammation, contributing to autoimmune diseases.

Delayed Healing

• Cortisol suppression of the inflammatory response slows down wound healing.

Obesity

• Cortisol promotes fat storage, particularly in the abdominal region, increasing the risk of various health problems.

Hormonal Imbalance

• Cortisol inhibits the production of hormones like LH, estradiol, and testosterone, potentially impacting reproduction.

Increased Sympathetic Nervous System Activity

• Heightened "fight-or-flight" response due to catecholamine release can lead to increased anxiety, elevated heart rate, and elevated blood pressure.

Reduced Serotonin Levels

• Cortisol can decrease serotonin levels, which are crucial for regulating mood, sleep, and appetite, impacting mental well-being.

Increased Stomach Acid

• Cortisol increases stomach acid production, potentially leading to digestive problems like heartburn and ulcers.

Increased Calcium Excretion

• Cortisol increases calcium excretion by kidneys, potentially contributing to bone loss and osteoporosis.

Sleep Disturbances

• Cortisol disruption of sleep cycles causes difficulty falling asleep or staying asleep, leading to fatigue, irritability, and impaired cognitive function.

Negative Effects of Increased Catecholamines

• Heart Issues: Increased heart rate and force, leading to myocardial remodeling (changes in heart structure) and a higher risk of heart diseases

• Myocardial Remodeling: Changes in heart muscle, including hypertrophy (enlargement), fibrosis (scarring), and apoptosis (cell death).

• Blood Vessel Constriction: Narrowing of blood vessels impacting peripheral arteries and blood supply.

• Peripheral Arteries: Reduced blood flow, causing pain, numbness, and potential tissue damage.

• Peripheral Arterioles: Reduced blood flow to tissues, decreasing oxygen and nutrient delivery

• Elevated Blood Glucose: Increase blood sugar due to cortisol action on the liver.

• Increased Lipolysis: Breakdown of fat, leading to increased free fatty acids and cholesterol in the bloodstream, contributing to cardiovascular disease and insulin resistance.

• Impaired Digestion: Cortisol inhibits smooth muscle contraction, potentially causing digestive problems like constipation.

Suppressed Immunity

• Cortisol inhibits immune responses, lowering the body's ability to fight infections.

Explore the complex relationship between stress and disease in this quiz. Learn how stress can contribute to various illnesses, impact brain function, and affect overall well-being. Delve into the types of stressors and their long-term effects on health.