PSYCHOPHYSIOLOGY OF THE NERVOUS SYSTEM UNDER STRESS

A basic concept in any study of stress is the acknowledgment of the link between what the brain says and the way the body behaves. This is known as the body-mind connection. The two are often inseparable and most studies on stress-related behavior emphasize the role of the brain and the biology of stress in great detail.

Print out a diagram to show the body-mind connection.

The following are some essential terms needed to understand the basic concepts of stress behavior and how we can use the body to tackle stress.

Autonomic nervous system: The central nervous system is composed of two main parts: the sympathetic nervous system and the parasympathetic system. The ANS controls heart rate, respiration, blood pressure, digestion, elimination, sensory intake & electrodermal responses.

Sympathetic nervous system: This part of the ANS is responsible for preparing the body to meet stress. Its responses include: increased heart rate, increased blood pressure, respiratory rate accelerating. The sympathetic nervous system also stimulates endocrine glands like the adrenal gland and thyroid to produce hormones. Adrenaline and noradrenaline and cortisol are some of the hormones produced by the adrenal cortex during the stress response.

Parasympathetic nervous system: This portion of the ANS is responsible for the relaxation response and brings the body back to the relaxed stage. If the sympathetic reactions are comparable to the accelerator of the car then the parasymapathetic responses are like the brakes.

The major reactions of the body during stress include:

• Increase in heart rate --> increased blood pressure.
• Increased respiration rates.
• The SNS also increases sweating and is obvious as the electrodermal response. Also termed palmar sweating, it is often accompanied by cold hands and feet. The cold hands and feet occur because of the vasoconstriction of the peripheral arteries that serve the hands and feet. The arteries are constricted by the medullary hormones.

Print out the Checklist on Physiological Signs of the flight/fight response.

Fight or Flight: Originally described by Walter Cannon, it is a short, intense stress reaction. Emergency reaction for survival. It is the immediate response of the body in the presence of a stressor. This response stimulates the sympathetic nervous system to prepare the body to meet the stress situation.