Stress: The body's response.

Stress: The body's response.

1. THE AUTONOMIC NERVOUS SYSTEM

   • THE SYMPATHETIC NERVOUS SYSTEM
     • THIS SYSTEM PREPARES THE BODY FOR FIGHT OR FLIGHT. IT INCREASES PHYSIOLOGICAL AROUSAL AND PREPARES THE BODY TO RESPOND TO THREATENING SITUATIONS QUICKLY. THE ACTIVATION OF THIS SYSTEM IS A VITAL PART OF THE BODY'S RESPONSE TO STRESSFUL STIMULI.
   • THE PARASYMPATHETIC NERVOUS SYSTEM
     • THIS IS THE SYSTEM THE BODY IS IN MOST OF THE TIME. IT IS CALLED REST AND DIGEST. THE SYMPATHETIC BRANCH SLOWS THE BODY DOWN AND IS USED IN NORMAL STATE - WHEN THE BODY IS NOT STRESSED.

2. THE HYPOTHALAMUS

   • THE HYPOTHALAMUS IS A GLAND IN THE BRAIN. IT IS RESPONSIBLE FOR MANY PHYSIOLOGICAL FACTORS SUCH AS HUNGER, THIRST AND STRESS. THIS SPECIFIC GLAND ACTIVATES THE SYMPATHETIC BRANCH OF THE AUTONOMIC NERVOUS SYSTEM AS WELL AS THE PITUITARY GLAND.
   • THE HORMONES
     • ADRENALINE INCREASES: ENERGY TO MUSCLES, HEART RATE, BREATHING RATE, BLOOD PRESSURE, SWEATING. SLOWS DOWN DIGESTION TO SAVE ENERGY FOR FIGHT OR FLIGHT.
     • NORADRENALINE INCREASES: BREATHING RATE, BLOOD PRESSURE, BLOOD FLOW TO MUSCLES. SLOWS DIGESTION AND RELEASES SUGAR FROM LIVER.
     • CORTISOL IS SECRETED WHEN DEALING WITH LONG TERM STRESS. IT HELPS MAINTAIN A STEADY SUPPLY OF BLOOD SUGAR FOR INCREASED ENERGY.

3. SHORT TERM STRESS: SYMPATHETICOMEDULLARY PATHWAY

   • HIGHER BRAIN CENTRES EVALUATE THE SITUATION AS STRESSFUL AND INSTRUCT THE HYPOTHALAMUS TO TRIGGER THE SYMPATHETIC BRANCH OF THE AUTONOMIC NERVOUS SYSTEM. THIS STIMULATES THE ADRENAL MEDULLA, VIA NERVES, RESULTING IN THE RELEASE OF ADRENALINE AND NORADRENALINE INTO THE BLOOD STREAM. THIS INCREASES THE HEART RATE AND BLOOD PRESSURE.
   • LONG TERM: PITUITARY-ADRENAL SYSTEM
     • HIGHER BRAIN CENTRES EVALUATE THE SITUATION AS STRESSFUL AND INSTRUCTS THE HYPOTHALAMUS TO STIMULATE THE PITUITARY GLAND. THE PITUITARY GLAND RELEASES ADRENOCORTICOTROPHIC HORMONE (ACTH). THIS TRAVELS TO THE ADRENAL CORTEX TO STIMULATE THE RELEASE OF CORTICOSTEROIDS - SPECIFICALLY CORTISOL - INTO THE BLOOD STREAM. THIS SUPPRESSES THE IMMUNE SYSTEM AND MOBILISES FAT STORES TO BE USED AS ENERGY.

4. THE IMMUNE SYSTEM

   • NATURAL IMMUNITY
     • THIS IS A PRIMITIVE SYSTEM COMPRISING OF WHITE BLOOD CELLS (NATURAL KILLER CELLS) THAT NON-SPECIFICALLY DESTROY INVADING PATHOGENS. THIS SYSTEM IS ACTIVATED WITHIN A FEW MINUTES OR HOURS.
   • SPECIFIC IMMUNITY
     • THIS IS A SOPHISTICATED SYSTEM. LYMPHOCYTE CELLS RECOGNISE INVADING PATHOGENS AND PRODUCE SPECIFIC ANTIBODIES TO DESTROY THE PATHOGEN. THIS EVOLVES OVER A FEW DAYS OR WEEKS AS IT TAKES TIME FOR THE BODY TO RECOGNISE PATHOGENS AND CREATE ANTIBODIES.
       • CELLULAR IMMUNITY
         • A VARIETY OF T LYMPHOCYTES LAUNCH AN INTERCELLULAR PATHOGENS. (THEY ATTACK FOREIGN CELLS HARBOURING VIRUSES)
       • HUMORAL IMMUNITY
         • B LYMPHOCYTES RELEASE ANTIBODIES TO ATTACK AND DESTROY EXTRACELLULAR PATHOGENS. B LYMPHOCYTES ARE INVOLVED IN INFECTION CONTROL.