Everyone experiences stress but defining it is difficult. Most people would suggest it refers to the physical consequences (such as heightened blood pressure, nausea, rapid heartbeat or not being able to sleep) which result from the failure to cope with physical or emotional demands (such as dealing with predators or sitting an exam). Bernard & Krupat (1994) suggested as well as these external factors, stress also involves a set of internal (or biological) factors. Any resulting physiological symptoms, he suggests, occur as an interaction of the two. Stress also varies in duration (Dienstbier, 1989); acute being the briefest and chronic lasting longer. This essay will focus the biological perspective of stress and attempt to demonstrate that it can be a hindrance but in some circumstances it can be a help.
From a biological perspective stress is any 'circumstance that upsets homeostasis' (Breedlove et al, 2010); that is the body's ability to maintain internal equilibrium. It is associated with altered activity in the Autonomic Nervous System (ANS) and the Hypothalamic-Pituitary Axis (HPA). It begins when neurons communicate with their neighbours by sending neurotransmitters across the synapse. Dopamine is the neurotransmitter activated in stress and it acts on the hypothalamus. The hypothalamus in turn acts on the ANS which releases two catecholamines (adrenalin and noradrenalin); it also stimulates the adrenal glands which release cortisol to increase metabolism which provides immediate energy. The hypothalamus also acts on the HPA by releasing CRF which in turn signals the pituitary to release ACTH. This affects the adrenal glands which release cortisol and adrenalin which helps to prolongs the response.