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 threshold
Resulting problem
Higher blood sugar
• Alters osmotic balance between
blood and extracellular fluids; can
lead to ↑ fluid uptake by the blood
and ↑ blood pressure
• ↑ water loss from nephron
↑ blood pressure
• Possible rupture of blood vessels
due to higher pressure
• ↑ blood clotting
↑ heart rate
• Can lead to ↑ blood pressure
• Possible damage to heart muscle
Too juiced!
FIN