Iris: Our pupils dilate to improve focus.tear ducts: Production of tears is halted so we can see clearly.
Sweat glands: Stimulated to secrete excess waste products. Therefore we begin to sweat.
Arteries: Arteries to the periphery contract increasing blood flow to the large skeletal muscles, heart and lungs. This results in us going pale and a cold feeling in the extremities.
Skin: External skin hair straightens to trap air to keep the body warm, which leads to more effective large muscles for running or fighting. We have often heard the expression ‘My hair stood on end’ used when people express fright or shock.
Heart: Heart is stimulated to increase blood flow. This can result in palpitations and you feel your heart racing. This can be measured by your increased pulse rate. Continued exposure to stress can lead to heart problems. Lungs: We unconsciously breathe very quickly taking shallow and fast breaths, this can give one the feeling of breathlessness. This allows us to take in more oxygen to supply the large muscles that aid in fight or flight. Prolonged exposure to stress can lead to breathlessness and exacerbation of respiratory conditions such as asthma.
Digestive System: The digestive system is shut down to conserve energy and to divert blood to the large muscle groups. The outward expression of this is a dry mouth feeling. Long term effects include indigestion, fluctuating weight, IBS and ulcers.
Adrenal glands: Stimulates the secretion of stress hormones (corticoids) such as adrenalin noradrenalin.
Bladder: The muscles in the bladder tighten to inhibit you from urinating. .
Anus: The muscles around the anus tighten to inhibit bowel movements. Long term effects of stress may include diarrhoea and constipation.
Sex organs: Blood flow to the sex organs is decreased and secretions of all glands are decreased leading to a lack of sexual sensation.