Ch. 9 Stress and Adaptation Flashcards
What is homeostasis?
State of constancy that requires feedback control systems and integrates a variety of body systems.
What are Cannon’s 4 features of homeostasis?
Mechanisms to maintain constancy.
Change from “steady-state” causes a response.
Response is multifactoral and cooperative. (Can be simultaneous or successive).
“Organized self-government”.
What is eustress?
Controllable (mild/brief) periods of stress contributing to emotional and intellectual growth
What is allostasis?
Interactive physiologic changes in neuroendocrine, autonomic, and immune systems in response to real or perceived challenges/threats to homeostasis.
What is the definition of stress? (Hans Selye)
“A state manifested by a specific syndrome of the body developed in response to any stimuli that made an intense systemic demand on it”
What is an endogenous stressor?
A stressor within the body.
What is an exogenous stressor?
A stressor outside the body.
What are the two things that the response to stress is dependent on?
Properties of the stressor and condition of the person being stressed.
What are the internal factors affecting the stress condition?
Genetic, age, gender
What are the external factors affecting the stress condition?
Environmental exposure, life experiences, dietary, social support
What is General Adaptive Syndrome? (GAS)
“General systemic reaction in response to a stressor resulting in physical manifestations coordinated and dependent on each other.”
What occurs during the alarm stage of general adaptation syndrome?
SNS and HPA axis stimulation
Release of catecholamines and cortisol
What occurs during the resistance stage of general adaptation syndrome?
Body responds and adapts
Cortisol levels drop
What occurs during the exhaustion stage of general adaptation syndrome?
Resources are depleted.
Damage to systems if prolonged.
What is the neuroendocrine system response?
Release of neurohormones in response to stress.
What does the release of neurohormones result in?
Energy Sharpened focus & awareness Increased cerebral blood flow and glucose utilization Enhanced CV and respiratory function Shunting of blood to brain/muscles Modulation of immune response Inhibition of reproductive function Decreased appetite
Which neurohormones are released as part of the stress response?
Catecholamines Cortisol Angiotensin II Aldosterone ADH
What is the effect of cortisol?
Potentiates epinephrine and glucagon
Decreases non-essential energy-using activities (metabolic rate, reproductive, osteoblasts, RBC/WBC production, immune system)
What occurs hormonally during the sympathetic “fight or flight” response?
Rapid response to trauma and emergency
Epinephrine & norepinephrine both released
Both attach to adrenergic receptors on cells
What are the effects of stress on the immune system?
Decreased immune cell production.
Decreased thymus activity (eventual atrophy)
Monocytes and lymphocytes release inflammatory mediators and cytokines which interfere with brain activities.
What are the physiologic reserve factors that influence the ability to adapt?
Ability of body systems to increase their function
RBCs, heart rate, vasodilation/constriction
What are the anotomic reserve factors that influence the ability to adapt?
Paired organs
What are some factors that affect the ability to adapt?
Time available to adapt Genetic endowment/acquisition Age Gender Health status Nutrition Sleep-wake cycles Hardiness Psychosocial factors
What are some things that can affect sleep-wake cycles?
Jet lag Pain Surgery Insomnia Sleep deprivation Loss (emotional) Stress Environment Shift work
