Aggression & Stress

Made by @agreyr

Aggression

Behavior intended to cause pain or harm

Hormonal contributions to aggression

Androgens seem to increase aggression in animals but story is more complicated in humans

Brain regions involved in aggression

Amygdala & ventromedial hypothalamus

Stress

The physiological changes that result when the body is exposed to harm or threat

Stressor

The experience that induces the stress response (bear, shock, exam, etc.); elicits the same response pattern whether psychological or physical stress

Stress pathways

Sympathetic nervous system (fight or flight, epinephrine) & HPA axis (stress hormone system, cortisol)

Hypothalamic-pituitary-adrenal (HPA) axis

Hypothalamus: Corticotropin Releasing Factor

Pituitary (anterior): Adrenocorticotropic Hormone

Adrenal gland: Cortisol

Hans Selye & stress research

Canadian physician who studied “ovarian extract” - injected rats daily with estrogen or control (saline) to investigate effects on stress

Results: ALL rats developed ulcers, enlarged adrenal glands, and shrinkage of the lymph nodes (stress response to injections)

Generalized Adaptation Syndrome

Three stage physiological stress response that appears regardless of the stressor that is encountered

Phase 1: Alarm reaction (mobilize resources)

Phase 2: Resistance (cope with stressor)

Phase 3: Exhaustion (reserves depleted)

Psychoneuroimmunology

Study of the interaction of psychological factors, the nervous system, and the immune system; includes biological factors

Stress and immune function

Acute stressors improve immune function; chronic stressors impair immune function

Brief stressors activate an inflammatory response (increased cytokines, peptide hormones that cause inflammation and fever)