Hormonal regulation of responses to stress

Adrenal Glands  “Adrenal” = At the kidneys.  The adrenal gland has an inner core called the adrenal medulla which is surrounded by the adrenal cortex.  The adrenal medulla produces two hormones: epinephrine and norepinephrine.  Epinephrine is also known as adrenaline.  Norepinephrine is also known as noradrenaline.  Both of these hormones are released by the adrenal medulla in times of stress.

Short Term Stress Response  Both norepinephrine and epinephrine are released during times of stress. They help initiate the fight or flight response. (Hypothalamus  Spine  Adrenals) –They increase blood sugar levels by converting glycogen into glucose. –They increase heart rate and breathing rate for faster delivery of oxygen and glucose to the cells. –This results in faster energy production and higher metabolic rate within the cell. –Blood vessels dilate (widen) to deliver more blood. –Pupils dilate to allow more light into eye to gather as much information from surroundings as possible.

Long Term Stress Response  “Long term stress” means the threat is not incredibly urgent or threatening – though it is constant and ever present.  Hypothalamus  Spine  Adrenal  Adrenals secrete glucocorticoids & mineralocorticoids – they help the body meet the demands of stress.  Glucocorticoids, including cortisol, promote conversion of fat and protein into glucose – blood sugar level goes up overall.  Mineralocorticoids increase water retention by kidneys and this results in higher blood pressure and blood volume – greater delivery of blood to cells.

Long Term Stress Response Shift in thresholdResulting problem Higher blood sugarAlters osmotic balance between blood and extracellular fluids; can lead to ↑ fluid uptake by the blood and ↑ blood pressure ↑ water loss from nephron ↑ blood pressurePossible rupture of blood vessels due to higher pressure ↑ blood clotting ↑ heart rateCan lead to ↑ blood pressure Possible damage to heart muscle

Too juiced!

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