Outline the bodily response to acute stress. (6 marks) › Autonomic nervous system is activated › Sympathetic branch prepares for fight or flight; heart rate increases (as well as pupil dilation, increased blood pressure and metabolic changes) › Noradrenaline is released by the SNS › Neurons of the SNS activate the adrenal medulla to release adrenaline, preparing for fight or flight; suppression of digestion occurs. Learning Objectives To understand the body’s response to chronic stress (Pituitary-Adrenal System). Success Criteria Draw a flowchart showing the pituitaryadrenal system Read through page 7 of your booklet. Challenge Criteria Create a 50 word summary of each stress response. This is also known as the body’s ‘stress system’ It controls cortisol levels and other stress hormones Activation of the pituitary-adrenal system is less easy to achieve › Sketch a copy of the system using page 135 of the textbook. C h r o n i c S t r e s s The hypothalamus is passed messages when stressors are received by the brain. A region of the hypothalamus is activated (paraventricular nucleus – PVN), and chemical messengers are produced (CRF). These are released into the bloodstream in response to the stressor. When CRF reaches the pituitary gland, ACTH (a hormone) is produced and released. ACTH is transported in the bloodstream to the adrenal glands, on top of the kidneys. Cortisol, released by the adrenal cortex, has positive and negative effects on the body. Positive = burst of energy and lower sensitivity to pain Negative = impaired cognitive performance, higher blood pressure, and lowered immune system Prolonged release of ACTH causes the adrenal cortex to increase in size to cope with cortisol production. Long-term ACTH deficiency causes the adrenal cortex to shrink. After 20 minutes of the perception of an acute stressor, cortisol levels have risen sharply. The hypothalamus and pituitary gland have special receptors to monitor cortisol levels; if cortisol gets too high, CRF and ACTH are reduced to bring cortisol levels back to normal. Create a 50 word summary of each stress response on your card 1. 2. 3. 4. 5. 6. The stressor activates the Pituitary-Adrenal System (AKA: Hypothalamic Pituitary Axis) The hypothalamus stimulates the pituitary gland The pituitary gland secretes ACTH ACTH stimulates the adrenal glands to produce the hormone cortisol Cortisol enables the body to maintain steady supplies of blood sugar Adequate and steady blood sugar levels help person to cope with prolonged stressor, and helps the body to return to normal Lets review the stress diaries from last week: › What were the most common stressors? › What were the most common uplifts? › Which days did you feel most stressed? Why? › What were the most common symptoms of stress? Learning Objectives To understand the body’s response to chronic stress (Pituitary-Adrenal System). Success Criteria Draw a flowchart showing the pituitaryadrenal system Read through page 7 of your booklet. Challenge Criteria Create a 50 word summary of each stress response.