Chapter 2: Homeostasis And Adaptive Responses To Stressors Flashcards
Homeostasis
A state of being in which all systems are in balance around a fairly narrow ideal “set-point”
Allostasis
A dynamic process that maintains or re-establishes homeostasis by varying or changing
Stress or Stressor
Physical, chemical, or emotional factor that produces tension in the body or the mind, but it can also mean the actual physical and mental state of tension. Can be real or perceived threat to homeostasis.
The stages of General Adaptation Syndrome (GAS)
Alarm, Resistance/Adaptation, and Exhaustion(Allostatic Overload)
Are all 3 stages presented after one stress?
No, it depends on the severity of the person’s situation
Norepinephrine
Constricts blood vessels, raises blood pressure, increases heart rate and cardiac output, causes bronchiodilation, increases glucose levels, and reduces gastric secretions
Adrenocortical Steroids
Critical to maintenance of homeostasis, can synergize or antagonize effects of catecholamines. Some examples are cortisol and aldosterone.
Cortisol
Primary glucocorticoid, inhibits protein synthesis resulting in immune suppresion, has anti-inflammatory effects which can result in sepsis
Aldosterone
Primary mineralocorticoid, promotes reabsorption of sodium and water, increases blood pressure and cardiac output
Sex Hormones
Affect stress responses which influences allostasis
Examples of Sex Hormones
Estrogen, testosterone, and dehydroepiandrosterone
Adaptation methods for stress
Habituation and Desensitization
Exhaustion (Allostatic Overload)
A point where the body can no longer return to homeostasis
Allostatic Overload
Cost of the body’s organs and tissues for an excessive or ineffectively regulated allostatic response meaning it’s the effect of the wear and tear on the body
Cardiac Output
CO = Stroke Volume x Heart Rate
