Chapter 2 Flashcards
Homeostasis
- remaining stable while staying the same
- a state in which all systems are in balance
- a state of equilibrium
an ideal set point despite alterations within the body
Allostasis
- the ability to successfully adapt to changes
- intricate regulatory processes orchestrated by the brain
- a dynamic process that maintains or reestablishes homeostasis in light of environmental and lifestyle changes
Stress
physical, chemical, or emotional factors resulting in tension of body or mind. A real or perceived threat to homeostasis
General Adaptation Syndrome (GAS)
3 stages
- alarm
- resistance/adaptation
- exhaustion
Alarm Stage
fight or flight response due to stressful stimulus
- Hypothalamic pituitary adrenal
(HPA) axis
Resistance/adaptation stage
activity of the nervous and endocrine systems in returning the body to homeostasis (allostatic state)
Exhaustion
the point where the body can no longer return to homeostasis
(results in allostatic overload)
Allostatic overload
cost of the body’s organs and tissues for an excessive or ineffectively regulated allostatic response; the effect of wear and tear on the body
Stressors
agents or conditions that can produce stress; endanger homeostasis
Risk factors
not a stressor, but conditions or situations that increase the likelihood of encountering a stressor
Catecholamines
- play an integral role in allostasis
- Sympathetco-adrenal system response mediates the fight or flight response
- Ex: Norepinephrine & epinephrine
Norepinehrine
- constricts blood vessels and raises blood pressure.
- Reduces gastric secretion. Increases night and far vision
Epinephrine
- Enhances myocardial contractility, increases heart rate, and increases cardiac output.
- Causes bronchodilation
- Increases release of glucose from liver (raises blood glucose levels)
Adrenocortical Steroids
- critical to maintenance of homeostasis
- may synergize or antagonize effects of catecholamines
- ex: cortisol and aldosterone
Cortisol
- primary glucocorticoid
- affects protein metabolism
- promotes appetite and food seeking behaviors
- has anti inflammatory effects
Aldosterone
- primary mineralocorticoid
- promotes reabsorption of sodium and water
- increase blood pressure
Endorphins and Enkephalins
Endogenous oipods (the body’s natural pain relievers)
- raise pain threshold and
produce sedation and
euphoria
Immune Cytokines
- Secreted by macrophages during stress response - enhance immune system response - prolonged stress can suppress immune functioning - interlukin 1
Sex hormones
- affect stress responses influencing allostasis
- may help explain gender responses during stress
- ex: estrogen, testosterone, and dehydroeiandrosterone
Growth Hormone
can increase during stress to enhance immune function
Prolactin
- similar to structure of growth hormone
- role in immune response
Oxytocin
- produced during childbirth and lactation
- associated with bonding and social attachment
- thought to moderate stress response and produce a calming effect
Effects of stress response influenced by
genetics socioeconomic status prior susceptibilities preexisting health status allostatic state ability to manage stress
Adaptation
process of change in response to new or altered circumstances, internal or external in origin
