Attracting Abundance

- 121 -

The Law

Belief - XXXIII

We will look at the effect of stress on our biology and behavior over the next two posts. The point to remember here is that whether the stress signal is based on reality or it is believed to be a stress point, we react the same way. For example if you see a lion coming towards you, your antennae for danger is activated irrespective of whether the lion is real or someone masquerading as a lion; it is your perception or belief that counts.

Homeostasis or equilibrium or stable state is a concept connected to stress. In biochemical processes, homeostasis is the ideal target but never achieved fully. Homeostasis is the ideal living condition for an organism. The environmental stimuli, both external and internal, continuously disrupt homeostasis keeping the present condition of the organism in constant flux. When the present condition of the organism moves far away from homeostasis, stress develops. But stress is not limited to this. When the organism's systems respond to try and bring back the present condition to homeostasis, stress persists.

Stress can be external and internal. The external signals of stress are from outside the body. We will see, how the body responds to them. The internal stress signals originate inside our body and caused by viruses, bacteria etc. Our immune system responds to the internal stress signals.

Stress is categorized in to two types: acute and chronic.

Acute stress results from specific events or situations that involve novelty, unpredictability, a threat to the ego, and leave us with a poor sense of control. This "on the spot" type of stress can be good for you because the stress hormones help your mind and body to deal with the situation with a focused approach i.e. everything else takes a backseat: psychologically and physiologically. Take for example a situation when you are involved in an accident or you are about to make a presentation in front of a group of people or take the case of an athlete who has poised himself on the starting block for a 100 meter sprint.You feel your heart beat in your throat, your awareness is narrowed down to the event on hand, and you are pumped up. These are signs of stress signals at work.

Chronic stress results from repeated exposure to situations that lead to release of stress signals. This type of stress weakens your mind and body. Chronic stress conditions keep the stress response system continuously activated. The body's available energy is largely spent on the organs responsible for responding to the stress, thereby starving the energy creating processes like digestion. Our immune system gets depressed. This also impedes the conscious mind, slowing down logical and analytical processes and enhances the activity of the subconscious mind making an individual give in to habitual responses or 'knee jerk" responses which more often that not prove to be detrimental. Prolonged chronic stress contributes to breakdown of many bodily systems and cause psychological disorders like depression. The effect on bodily systems may manifest as high blood sugar, high blood pressure etc. which are basically the response signals for meeting the higher energy needs of relevant organs during during stress. There are certain behavioral changes associated with chronic stress: smoking, eating disorders, sleep disorders, irritability etc. Chronic stresses decrease the adaptability of an organism to changes.

There is one important thing to remember here though. There are some people who manage chronic stress well. There are some professions which have an inbuilt chronic stress factor, for example the stock traders. That aside the modern day lifestyle has significant components of chronic stress built in to the lifestyle. Psychologists are researching in to the "hardiness" phenomena of some people who are chronically stressed and still remain healthy, pleasant and loving. This is a very interesting area.

The research work done in University of Wisconsin - Madison has come up with an important conclusion that it isn't the stress that causes the increased risk of illness, it is actually the perception that stress is harmful. We, now, understand that chronic stresses result from stressful events that persist over a long time, such as caring for a permanently disabled person close to you, or from brief focal events - past memories - that we continue to experience even after that event has passed in to history such as a sexual assault. The "hardy" people are probably able to dis-connect quicker and efficiently from stress events. People who do not believe that stress will affect their health, do manage stress much better. This suggests that there are individual differences in vulnerability to the potential pathogenic effects of stress; individual differences in vulnerability arise due to both genetic factors, age and primarily due to perception or belief.

The research work on animals has conclusively that stress contributes to initiation, growth and metastasis of certain tumors, but studies that have tried to link stress with cancer in human beings have shown mixed results. this may be due to practical difficulties in designing and implementing adequate studies.

The central nervous system, comprising of brain and the spinal cord, together with the body's endocrine system (collection of glands of an organism that secret hormones directly in to the organisms circulatory system to be carried towards distant organs) regulate the stress reception- response processes. The sympathetic nervous system, which is a part of the autonomic nervous system, becomes active during the response phase, regulating the body's biological functions in ways that ought to make an organism more adaptive to its environment. (autonomic nervous system regulates key involuntary functions of the body, including the heart muscle, the smooth muscles, including the muscles of the intestinal tracts and the glands. The autonomic nervous system is divided in to two parts: the sympathetic nervous system which accelerates the heart rate, constricts blood vessels, raises blood pressure, and the parasympathetic nervous system which slows the heaart rate, increases intestinal and gland activity and relaxes sphincter muscles) We will briefly discuss the neuro - anatomy and neuro - chemistry involved in the stress reception - response processes.

Human brain: Hypothalamus =     , amygdala =     , hippocampus/fornix=     , pons=     , pituitary gland=     

The important brain structures which are involved in stress related processes are as follows:

• Hypothalamus: located just above the brain stem and below thalamus, it links the body's nervous system and endocrine system. When the brain senses stress from the signals that it receives from sensory organs like eyes, ears etc,, the hypothalamus releases  hormones, corticotropin-releasing hormone (CRH) , which stimulates the pituitary gland.(corticotropin-releasing hormone is the neurohormone secreted by hypothalamus during a stress response that stimulates the anterior lobe of the pituitary gland by binding to its coticotropin-releasing hormone receptor, causing the anterior pituitary to release adernocoticotropic hormone.).         (Neuropeptide Y is a protein that is synthesized in the hypothalamus and acts as a chemical messenger in the brain. Recent research work has revealed that this is also involved in stress and anxiety, specially stress resilience)
• Amygdala: is a small almond shaped structure, two of which are located deep within the brain. The amydalae are part of brain's limbic system ( limbic system is a complex system of nerves and networks in the brain, involving several areas near the edge of the cortex concerned with instinct and mood. It controls the basic emotions (fear, pleasure, anger and drives hunger, sex, care of offspring and dominance) with projections to and from the hypothalamus, hippocampus, and locus coeruleus among other areas. It processes emotions and modulates stress response mechanismsm specially when feelings of anxiety or fear are involved.
• Hippocampus: is a structure located just below each amygdala and is a part of brains limbic system. It plays an important role in memory formation. During stress, hippocampus plays a particularly important role in that its cognitive processes such as prior memories can have a huge influence on enhancing, suppressing, or even independently generating a stress response. Chronic stress may damage hippocampus.
• Prefrontal cortex; regulates cognitive processes like planning, attention, and problem solving through extensive connections with other brain regions. This is also susceptible to impairment during stress response.
• Locus coeruleus: is located in the pons of the brainstem that is the principal site of the synthesis of the neurotransmitter norepinephrine (noadrenaline) (norepinephrine is the primary chemical messenger of the central nervous system's sympathetic branch that prepares the body for fight or flight) which plays an important role in the sympathetic nervous system's fight-or-flight response to stress. This area receives inputs from hypothalamus, and amygdala among other regions and projects widely across the brain as well as to the spinal cord.
• Raphe nucleus: is located in the pons that is the principal site for synthesis of neurotransmitter serotonin, which plays an important role in mood regulation, particularly when stress is associated with anxiety and depression. Projections extend from this region to widespread regions of the brain and modulate an organism's circadian rhythm and sensation of pain among other processes.
• Spinal cord: has the critical function of transferring stress respons  neural impulses from the brain to the rest of the body. In addition to the neuro-endocrine blood hormone signalling adopted by the hypothalamus, the spinal cord communicates with the rest of the body by innervating the peripheral nervous system. Certain nerves that belong to the sympathetic branch of the central nervous system exit at spinal cord and stimulate peripheral nerves, which in turn engage the body's major organs and muscles in fight-or-flight response.
• Pituitary gland: is located just under the hypothalamus. It releases various hormones that play crucial role in regulating homeostasis. During a stress response, this gland releases adrenocorticotropine (ACTH) (Once released in to the blood stream, ACTH stimulates the cortex of the adrenal gland by binding to the ACTH hormone-receptor, thus causing adrenal gland to release cortisol), a hormone that modulates a heavily regulated stress response system.
• Adrenal gland: a major organ of the endocrine system that is located directly above the kidneys and is chiefly responsible for the synthesis of stress hormones that are released in to the blood stream during a stress response. Cortisol is the major stress hormone released by adrenal gland. (Cortisol's major function is to redistribute energy in the form of glucose to regions of the body that need it most viz. brain, major muscles during a flight-or-fight situation. It also depresses the immune system during stress. Cortisol is synthesized from cholesterol.) It also releases norepinephrine within during a stress response which acts as a hormone in the endocrine system.
• Peripheral nervous system: consists of the somatic nervous system and the autonomic nervous system. When a physical stressor acts upon the body the sensory-somatic nervous system gets activated through stimulation of body's sensory nerves. The signal acts as a nerve impulse and travels through the body in a process of electrical cell-to-cell communication until it reaches the autonomic nervous system which then immediately triggers a series of involuntary chemical responses throughout the body. Noradrenaline is one such chemical which flows in to the bloodstream directly ensuring that all cells in the body's nervous and endocrine systems have been activated.
• Endocrine system: When a stressor acts upon the body, the endocrine system is triggered by release of noradrenaline neurotransmitter by the autonomic nervous system. The  HPA (hypothalamus-pituitary-adrenal) axis gets activated. The sequence of activity after the HPA axis gets activated will be discussed in the next post.
• Central nervous system: is made up of the brain and spinal cord. Brain processes stress in three areas.: the amygdala, the hippocampus, and the prefrontal cortex. Each of the these areas is densely populated with cortico receptors which process the intensity of physical and psychological stressors acting upon the body. There are two types of cortico receptors. One type has very good affinity for cortisol and therefore are almost always remain partially activated. The second type has low affinity for cortisol and gets activated only when the brain starts to sense the stress at high intensity. As the second type of receptors start to get activated, neurons in the amugdala, hippocampus and prefrontal cortex become over stimulated. This stimulation of the neurons triggers a fight-or-flight response, allows the brain to act faster by using the subconscious mind patterns and deal with the threatening situations. If the acute stress levels prolong very long to a chronic stage, the hyperactivity of the neurons begin to physically change the brain and have severe damaging effects on one's mental health. 
• Immune system: Stress affects the immune system in many ways. The immune system protects the body from viruses, bacteria, and anything that the body does not recognize. The immune system sees these as intruders and attempts to destroy these. The white blood cells, leukocytes, are very important to the immune system. White blood cells have several types including B cells, T cells, and natural killer cells. B cells secrete antibodies. T cells attack intruders and natural killer cells attack the cells that have been infected by viruses. These leukocytes produce cytokines which fight infections. They also are the immune system communicators in telling the brain that the body is ill. When an individual is stressed or going through a stressful experience the immune system starts to produce killer cells and cytokines. When levels of cytokines are higher, the brain gets the message that the body is ill and it produces symptoms of illness viz. fever, low energy, low appetite, flu like symptoms etc. these symptoms indicate that the body is fighting the illness. Such symptoms also appear when stressors come up not due to illness but due to stressful events like examinations, job interviews, death in the family etc. and the individual who is undergoing such experience will start to feel that he is biologically ill. The most important aspect of the immune system are the T-cells and T-suppressor cell. When cortisol is released in to the bloodstream, it begins to cause division of T-suppressor cells. The number of T-suppressor cells increases rapidly while at the same time T-helper cells get suppressed. This reduces immune protection and leaves the body vulnerable to disease and infection.

Namaste

See you again

Prabir