Short-term and Long-term responses

 An important adaptation  Prepares us to take action that is evolutionarily important  Keep from being eaten  Find food  Find a mate

 Response to significant external stress termed ‘fight or flight’  Response diverts energy and resources to systems for fast response  Nervous  Endocrine  Cardiovascular  Muscular

 Function: works with nervous system to maintain homeostasis.  Structure: endocrine glands secrete hormones into the blood stream.  Hormones are chemical signaling molecules that bind to specific receptors on target cells only. Target cells respond by performing specific biochemical activities.  Hormones constantly broken down by enzymes and excreted in urine.  Long term response of target cells requires continuous binding of hormones.

 Fight or flight is a short-term response  Response – fight or flight – is designed to remove the stressor  When stressor is removed, response stops  If stressors are not removed, stress response continues

 Fight or Flight video Fight or Flight video

 Termed SAM system = sympathetic – adrenal medullary system  Both nervous and endocrine systems are part of response  Sympathetic division of autonomic nervous system stimulates adrenal medulla to produce hormones

Sense Organs Detect stimuli Hypothalamus Initiates autonomic response and stimulates adrenal gland Adrenal gland (medulla) Produces epinephrine and norepinephrine Target Tissues Heart, blood vessels, liver, etc.

 Blood flow increased to muscles/decreased to skin and digestive organs  Respiration increases  Blood sugar levels are elevated  Oxygen + glucose + blood flow = cell respiration  Cell respiration = energy

 Termed HPAC system = hypothalamus, pituitary, adrenal cortex system  Entirely endocrine system  Effects start slowly, but last longer compared to SAM system

Sense Organs Detect stimuli Hypothalamus Initiates autonomic response and stimulates pituitary gland Anterior Pituitary Gland Produces ACTH Adrenal Cortex Cortisol released. Target Tissues Long term adjustments

 Cortisol effects are primarily metabolic  Decrease protein synthesis  Increase blood fat and blood glucose

 Cardiovascular disease  Increased blood pressure  Increased blood fats  Fat storage  Increased blood fats (not used)  Increased blood glucose (not used)  Decreased Immune Response  CV Disease  Cancer  Decreased Brain Function