Stress Biology Learning Path

Definition of stress and stressor

Stress (physiological, biological, or psychological) is an organism’s response to a stressor—such as an environmental condition or a change in life circumstances. When stimuli disrupt an organism’s environment, multiple body systems respond, particularly in humans and most mammals via the autonomic nervous system (ANS) and the hypothalamic-pituitary-adrenal (HPA) axis. Well-known stress-related hormones include adrenaline and cortisol, which help coordinate short-term adaptation and influence many bodily functions (metabolic, psychological, and immunological). Through these mechanisms, stress can affect processes such as memory, reward, immune function, metabolism, and disease susceptibility. A stressor is the triggering demand or event that upsets homeostasis (the body’s equilibrium). Disruptions to psychological or physical equilibrium activate nervous, endocrine, and immune responses, producing physical changes with both short- and long-term effects. In psychology, stress can arise when situations are appraised as threatening or challenging, and chronic stressors—especially those that persist and require daily physiological activation—are more likely to contribute to health problems. Stress can also be conceptualized as potentially beneficial (eustress) when it enhances functioning, or harmful (distress) when it is persistent and not resolved through coping or adaptation.

0/2 modes complete

Homeostasis and equilibrium in biology

0/2 modes complete