Untitled Quiz

Stress and Disease Overview

• Stress is a condition where demands exceed coping abilities, disrupting cognition, emotion, and behavior.
• Psychological stress is a cause or contributing factor in many diseases, including mental illness.
• Psychological stress can worsen symptoms and outcomes of various diseases.
• Severe emotional stress is linked to poor cardiac health outcomes.
• Stressful events often cause insomnia, appetite changes, and physical illness.
• Chronic stress accelerates brain aging, reducing synaptic function and causing hippocampal atrophy (leading to memory loss)
• Early-life chronic stress can permanently alter physiological, psychological, and behavioral responses to stress.
• Animal studies show that brain changes due to chronic stress are irreversible.
• Stressors include fear, anxiety, anger, major life events, trauma, abuse, violence, daily hassles, school/work pressures, relationships, caregiving, diseases/illnesses, infections, pain, surgery, lack of sleep, insomnia, malnutrition, prolonged exertion, noise, and extreme temperatures.
• A person's interpretation of a situation is crucial to the stress response.

Categories of Stressors

• Acute stressors
• Chronic stressors
• Micro stressors

Concept of Allostatic Load

• Allostatic load is the wear and tear on the body from chronic or repeated stress.
• It's caused by exposure to various stressors over time, an inability to adapt to repeated stressors, delayed shutdown of the stress response, or inadequate stress response that necessitates compensation from other mediators.
• Constant exposure to stress hormones due to allostatic load leads to immune dysfunction, disease acceleration, and brain alteration.

Stress Response Categories

• Reactive: Physiological response to stressors
• Anticipatory: Physical responses in anticipation of a stressor
• Conditional: Learned response to a specific stimulus (danger) and the physiological response.
• Post-traumatic stress disorder (PTSD): Develops after an event involving harm or threat, with stress responses triggered by flashbacks.

Central Stress Response

• Central stress response involves brain regions, including the cerebral cortex.
• Sensory information is perceived in the cortex and relayed to the limbic system (amygdala, hippocampus, and hypothalamus).
• The amygdala registers fear and plays roles in emotion and decision-making.
• The hippocampus is central to memory and is situated near the amygdala.
• The hypothalamic-pituitary axis receives signals from the amygdala and hippocampus about stress, registering stress and pain. Hypothalamus signals the release of CRH, ACTH, then cortisol.
• The sympathetic nervous system is activated by stress and CRH, causing norepinephrine and epinephrine release.
• The hypothalamus also stimulates the release of TSH, leading to T3/T4 production.
• Paraventricular nucleus stimulation releases ADH and oxytocin from the posterior pituitary.
• The brainstem’s locus ceruleus neurons release norepinephrine, increasing brain activity and contributing to the widespread sympathetic stress response.

Negative Effects of Increased Cortisol

• Elevated blood glucose levels (insulin resistance, metabolic syndrome, Type 2 diabetes)
• Impaired immune and inflammatory responses (immunosuppression, infection, cancer, sepsis)
• Reduced wound healing
• Development of truncal obesity and weight gain (lipogenesis)
• Cardiovascular disease, atherosclerosis, coronary artery disease (CAD), myocardial infarction (MI), and heart failure.
• Inhibition of LH, estradiol, and testosterone (infertility, osteoporosis)
• Elevated SNS activity (hypertension, heart failure, kidney disease, atherosclerosis)
• Reduced serotonin levels (depression, anxiety)
• Promotion of gastric acid and enzyme secretion (peptic ulcers, gastroesophageal reflux disease (GERD))
• Increased calcium excretion (kidney stones)
• Disrupted sleep cycles (insomnia)

Negative Effects of Increased Catecholamines

• Elevated heart rate, myocardial remodeling, and heart failure.
• Peripheral artery vasoconstriction (hypertension)
• Reduced blood flow to tissues (GI ischemia, ulcers, constipation, bowel obstructions, skin ulcerations).
• Elevated blood glucose levels (insulin resistance, metabolic syndrome, and type 2 diabetes).
• Increased lipolysis, leading to elevated free fatty acids and cholesterol levels (atherosclerosis).
• Inhibition of GI smooth muscle, increased sphincter tone (constipation and bowel obstruction).
• Impairment of immune and inflammatory responses (immunosuppression, infection, cancer, sepsis).