Abstract
This chapter provides a general overview and introduces concepts related to major biological pathways involved in how stress, and other psychological factors can affect health outcomes. We start with scientists who have introduced the key terms and concepts of the field by investigating how stress affects our functioning, and present a psychosomatic model of disease. In the subsequent parts three major biological pathways are discussed. 1. Autonomic functioning of the sympathetic nervous system with adrenaline as the excitatory stress hormone, and the parasympathetic nervous system involved in rest. 2. The hypothalamus-pituitary-adrenal (HPA) axis with cortisol as a regulatory hormone. 3. The immune system affects our ability to conquer disease. The immune system is also affected by stress and psychological states, having a large effect on health and disease. Finally, a combination of these three major regulatory mechanisms is integrated and measurement issues and pitfalls are discussed.