BODILY RESPONSE TO STRESS The immune system

RECAP ACUTE STRESS RESPONSE CHRONIC STRESS RESPONSE

Place the terms in the correct column SAM HYPOTHALAMUS HPA PITUITARY GLAND ANS (SYMPATHETIC) ACTH ADRENAL MEDULLA PROTEINS & FATS MADE AVAILABLE FOR ENERGY ADRENAL CORTEX ADRENALINE CORTISOL FIGHT OR FLIGHT RESPONSE (INC GLUCOSE RELEASED INTO BLOODSTREAM) ACUTE STRESSOR IDENTIFIED CHRONIC (ONGOING) STRESSOR PERSISTS

Place the terms in the correct column SAM HYPOTHALAMUS HPA Acute Stressor indentified PITUITARY GLAND Hypothalamus ANS (SYMPATHETIC) ANS ACTH Adrenal medulla ADRENAL MEDULLA Adrenaline released PROTEINS & FATS MADE AVAILABLE FOR ENERGY Fight or flight response… ADRENAL CORTEX ADRENALINE RELAEASED CORTISOL RELEASED FIGHT OR FLIGHT RESPONSE (INC GLUCOSE RELEASED INTO BLOODSTREAM) ACUTE STRESSOR IDENTIFIED CHRONIC (ONGOING) STRESSOR PERSISTS

Place the terms in the correct column SAM HYPOTHALAMUS HPA Acute Stressor indentified PITUITARY GLAND Chronic (ongoing stressor persists) Hypothalamus ANS (SYMPATHETIC) ANS ACTH Pituitary gland Adrenal medulla ADRENAL MEDULLA Adrenaline released PROTEINS & FATS MADE AVAILABLE FOR ENERGY Adrenal cortex Fight or flight response… ADRENAL CORTEX Cortisol released ADRENALINE RELAEASED Proteins & fats made available for energy CORTISOL RELEASED FIGHT OR FLIGHT RESPONSE (INC GLUCOSE RELEASED INTO BLOODSTREAM) ACUTE STRESSOR IDENTIFIED CHRONIC (ONGOING) STRESSOR PERSISTS

The immune system White blood cells (leucocytes) produced in the spleen, lymph nodes, thymus (T cells) & bone marrow (B cells) Three main types are Granulocytes & monocytes which (ingest bacteria & viruses) Lymphocytes, including for example B lymphocytes which produce antibodies, beginning the process of destroying the antigen

How does stress affect the immune response Corticosteroids (including cortisol) cause proteins to be converted into energy to maintain the supply in times of chronic stress This reduces the production of leucocytes, so stress makes us less able to fight off infections Various infectious illnesses have been linked to stressful events including influenza & herpes

Research evidence Riley (1981) Study 1 Put mice on a rotating turntable AT 45 rpm Lymphocyte count decreased over a 5-hour period Study 2 Implanted cancer cells in 2 groups of mice Group 1 had 10 mins x 3 times per hour on the turntable for 3 days Group 2 had no rotation Mice in group 1 developed large tumours Mice in group 2 had no tumour growth

Research evidence Kiecolt-Glaser 1995 Study 1 Group A = women with high stress (caring for relatives with Alzheimer’s disease) Group B = a ‘stress-free’ control group All participants were given a small wound on their forearms It took 9 days longer on average for wounds to heal for women in the high stress group Study 2 Took blood samples from 75 first year medical students (volunteer sample), one month before exams and then again on the first day of their exams. Blood samples analysed for killer T-cell activity Killer T-cell activity was greatly reduced in the second sample. Weakest immune responses were found in students who reported: 1. feeling most lonely, 2. experiencing stressful life events, 3. experiencing psychiatric symptoms such as depression and anxiety.

Over to you Outline the conclusion you can draw from the Reily & Kiecolt- Glaser studies Evaluate the studies: Consider the methods used. Would you criticise (positive or negative) the procedure in any way? How confident are you that the findings demonstrate a link between stress and loss of immune function in humans? Could you interpret the findings any differently? Consider ethical issues in the studies