Stress As A Bodily Response
Seyle (1950) defines stress as "the nonspecific response of the body to any demand"
Stress - a generalised reaction to a demand placed on the body
Stressors - demands or events that throw the body out of balance and force in to respond
Stress Response - an innate, defensive and adaptive reaction that promotes survival
The Role of The Autonomic Nervous System
The nervous system is divided into two systems;
- The Central Nervous System: the brain and the spinal cord
- The Peripheral Nervous System: all the other nerve cells in the body
The PNS is further subdivided into;
- The Somatic Nervous System: concerned with voluntary movements of skeletal muscles
- The Autonomic Nervous System: concerned with involuntary movements of non-skeletal muscles. The ANS is a largely automatic or slef-regulating system, which means it respons with no or little conscious thought.
The ANS has two general functions; to activate internal organs and save energy. These functions are represented in two branches.
The Sympathetic Branch - activates internal organs in situations needing energy and arousal (like fight or flight). The sympathetic nervous system produces increased heart heart, reduced activity in the stomach, pupil dialation, glucose is released, and relaxation of the bronchi in the lungs.
The Parasympathetic Branch - involved when the body is trying to conserve and store its resources. It monitors the relaxed state, and promotes digestion and metabolism. The parasympathetic nervous system reacts as an opposite to the sympathetic nervous system so it produces decreased heart rate, increased activity within the stomach, pupil contraction, glucose is stored, and constrictions of the bronchi of the lungs.
Althought the parasympathetic nervous system and sympathetic nervous system often operate opposite to eachother, they sometimes have to work together to achieve a goal. For example; when a male is having sex, he must obtain an erection using the parasympathetic nervous system and ejaculate using the symapthetic nervous system.
The ANS achieves its efforts via the endocrine system, which consists of various ductless glands. The endocrine glands secrete hormones into the blood stream - these hormones control ANS activity.
The Nervous System;
- consists of nerve cells
- acts by transmitting nerve impulses
- acts rapidly
- direct control
- specific localised effects of neurotransmitters
- short-lived effects
The Endocrine System;
- consists of ductless glands
- acts by release of hormones
- acts slowly
- indirect control
- hormones spread around the body
- hormones remain in the blood for some time
Hormones can have effects on our behaviour and emotions which can be regarded in part as an emotional reaction to stressors. Most hormones are slow acting because they are carried around the body slowly by the bloodstream. The effects of hormones last for some time but typically gradually diminish as the situation becomes less stressful.
The body's internal environment generally remains almost constant in spite of large changes in the external environment. This homeostatis is the result of ANS activity and is a fundamental part of the stress response. When…