Stress Regulation (Hybrid) PDF

Endocrine System Stress Regulation What is stress?  The feeling of alarm or distress when reacting to particular event  Can be physical, emotional, cognitive or mental Stress Response  Natural response  Prepares an individual to handle the stressor (an event that provokes stress)  Typ...

Endocrine System Stress Regulation What is stress?  The feeling of alarm or distress when reacting to particular event  Can be physical, emotional, cognitive or mental Stress Response  Natural response  Prepares an individual to handle the stressor (an event that provokes stress)  Types:  Short term: responses are immediate  Long term: responses are ongoing and can cause detrimental side effects on the individual Adrenal Gland  Secretes stress response hormones  Location: adjacent to kidneys  Structure:  Adrenal cortex : outer portion, involved with long- term stress response  Adrenal medulla : inner portion, involved with short-term stress response Short Term Stress Response Short-term Stress Response  Stress excites nerve cells to release a neurotransmitter: acetylcholine (ACh)  Stimulates adrenal medulla to release catecholamines: epinephrine and norepinephrine Catecholamines  Synthesized from tyrosine  Secreted in response to positive or negative stress by the adrenal medulla  Types:  Epinephrine (adrenaline)  Norepinephrine (noradrenaline) Catecholamines Tyrosine Effects  Stimulates the “fight-or-flight” response  Increase metabolism  Cellular respiration produces ATP  Need energy source (glucose)  Need oxygen Effects: Energy Source  Increased blood glucose levels  Glycogen → glucose  more ATP readily available  Stimulates the release of fatty acids from fat cells to supply the body with more energy  Decreased kidney and digestive activity Effects: Oxygen  Increased blood pressure and blood flow  oxygen is distributed to cells faster  Increased breathing rate  Relaxes/contracts certain blood vessels  overall effect of redirecting blood away from non- vital areas  increasing blood flow to the heart, brain, and skeletal muscles  Increased alertness Short-term Stress Response Adrenal medulla stress Epinephrine Breakdown glucose Increased blood volume, Increase blood glucose pressure, breathing rate Increased energy source Increased oxygen Fight or flight in response to stress Application  Epinephrine is present in epinephrine autoinjectors (EpiPens) Long Term Stress Response Long-Term Stress Response: Neuroendocrine pathway  CRH  ACTH  Corticosteroid  Glucocorticoid  Mineralcorticoid  Long-Term Stress Response: Neuroendocrine pathway Location Hormone Stimulus Stress Hypothalamus Corticotropin-releasing Hormone (CRH) Anterior Pituitary Adrenocorticotropic Hormone (ACTH) Adrenal Cortex Corticosteroids: Glucocorticoids (e.g. cortisol) Mineralocoritcoids (e.g. aldosterone) Effect Increase glucose production Increase oxygen delivery Corticotropin-Releasing Hormone (CRH)  Peptide hormone  Tropic hormone  Released from hypothalamus  Stimulus: stress  Effect: Stimulates anterior pituitary to synthesize ACTH Adrenocorticotropic Hormone (ACTH)  Peptide hormone  Tropic hormone  Produced from anterior pituitary  Effect: Stimulates adrenal cortex to synthesize corticosteroids  Corticosteroids  steroids produced and released from the adrenal cortex Type Example Glucocorticoid Cortisol Mineralcorticoid Aldosterone Sex hormones testosterone Glucocorticoid (Cortisol) Effects: Energy source  Affects glucose metabolism  Raise blood glucose levels by synthesizing glucose from non-carbohydrate sources:  Breakdown of fat to glucose  Liver breaks down muscle protein in skeletal muscles to glucose  Occurs when body needs more glucose than what the liver can produce from its storage of glycogen  Other effects:  Suppress immune system  Natural anti-inflammatory (antihistamine) Mineralocorticoid (Aldosterone) Effects: Indirectly on oxygen  Hormone that affects the body’s osmotic balance  Stimulates reabsorption of salt and water by kidneys  Cause increase in blood volume and pressure  Increase oxygen delivery Long-term Stress Response Hypothalamus stress CRH Anterior pituitary ACTH Mineralcorticoid Glucocorticoid (cortisol) (aldosterone) Synthesize glucose from Increased reabsorption, non-carbohydrate source blood volume, pressure Increased energy source Increased oxygen Increased cellular respiration  Compare Short & Long Term Stress Management Stress Short term Long term Hormones Epinephrine Glucocorticoid (cortisol) Norepinephrine Mineralcorticoid (aldosterone) Energy Glucose from Glucose from non- glycogen stores carbohydrate source Oxygen Increase heart Increase reabsorption rate, pressure, flow of salt and water, blood & resp rate, volume, pressure & regulate vessel size flow