Stress and Homeostasis Flashcards
What is homeostasis?
balanced. maintain stable internal conditions necessary for survival. (goldie locks)
What are stressors in the context of homeostasis?
External or internal conditions that challenge homeostasis, requiring the body to adapt.
What is the body’s response to stress
Adaptation, which helps restore homeostasis. Failure to adapt leads to illness or death.
What is a negative feedback loop in homeostasis?
opposes a change to return the body to a set point (e.g., thermoregulation, blood sugar regulation). Brake petal STOP
Give an example of a positive feedback loop
Childbirth: Baby’s head presses on cervix, signals brain to release oxytocin, increases contractions, more pressure on cervix, leading to further contractions.
What is the central stress response?
Brain-based response involving arousal, alertness, and inhibition of non-essential functions (e.g., reproduction, growth).
What is the peripheral stress response?
Increased respiration, cardiovascular tone, and nutrient distribution to the brain, heart, and skeletal muscles.
What are the three phases of the stress response?
- Alarm 2. Resistance 3. Exhaustion
What happens during the alarm phase of stress?
The body detects the stressor and initiates the “fight or flight” response through the hypothalamus.
What is the role of the hypothalamus in stress?
The hypothalamus acts as the control center, triggering the stress response by communicating with effectors.
What is the HPA axis?
Hypothalamus-Pituitary-Adrenal axis: A system that regulates stress through cortisol production, promoting adaptation to chronic stress.
What is the role of cortisol in stress?
A glucocorticoid hormone that increases blood glucose, regulates Na+/K+ balance, and suppresses immune responses during stress.
What is the sympatho-adrenal medullary (SAS) system?
A stress response system mediated by the sympathetic nervous system, secreting catecholamines (epinephrine and norepinephrine) for “fight or flight.”
What are catecholamines and their role in stress?
Hormones like epinephrine and norepinephrine that increase heart rate, blood pressure, and prepare the body for acute stress.
What happens during the exhaustion phase of stress?
body’s compensatory mechanisms fail, leading to potential illness, disability, or death if homeostasis is not restored.
What is compensatory reserve in stress?
The body’s ability to maintain homeostasis before its compensatory mechanisms are overwhelmed.
What factors affect compensatory reserve?
Age, health status, duration and intensity of the stressor
How can clinical management increase compensatory reserve?
By addressing the underlying problem (e.g., stopping blood loss, providing IV fluids, administering vasopressors).
What is the function of the autonomic nervous system in stress?
It controls involuntary responses, with the sympathetic division activating the “fight or flight” response and the parasympathetic division promoting rest.
What is physiological stress?
Any external or internal condition that challenges the homeostasis of a cell or organism.
What is adaptation in response to stress?
body adjusts to restore homeostasis after a stressor.
What are the central functions during a stress response?
Arousal, alertness, cognition, and inhibition of non-essential functions like reproduction and growth.
What are the peripheral functions during a stress response?
Increased respiration, cardiovascular tone, and nutrient delivery to vital organs (brain, heart, skeletal muscles).
What are peripheral chemoreceptors?
Receptors that detect changes in blood pH and help regulate breathing and oxygenation.
What is the role of the control center in homeostasis?
It processes information from receptors, compares it to the set point, and stimulates a response to maintain balance.
What is the role of the hypothalamus in homeostasis?
It regulates body functions such as temperature, blood pressure, and circadian rhythms through homeostatic mechanisms.
What is an effector in homeostasis
An organ or tissue that acts to restore homeostasis in response to signals from the control center.
What is the role of the renal tubules in homeostasis?
They reabsorb water and adjust blood osmolality as part of the homeostatic response to dehydration or fluid imbalance.
What is a stressor in the context of homeostasis?
Any physical, chemical, or environmental factor that causes a deviation from the body’s normal state.
What is the role of receptors in homeostasis?
They detect changes in the environment and forward the information to the control center for processing.
What is the role of a negative feedback loop in homeostasis?
It reduces or opposes a change to bring the body back to its set point, maintaining balance.
What is the positive feedback loop in homeostasis?
It amplifies or enhances a change, pushing the body further from the set point, often seen in processes like childbirth and blood clotting.
What is thermoregulation?
The process by which the body maintains a stable internal temperature, usually through negative feedback mechanisms.
How does the body regulate blood glucose?
Insulin lowers blood glucose when high; glucagon raises it when low, both through negative feedback loops.
What is the role of epinephrine in the stress response?
It increases heart rate, blood pressure, and energy availability for the “fight or flight” response.
What is the role of norepinephrine in the stress response?
It helps maintain blood pressure and enhances the contractility of cardiac muscles during stress.
What is the autonomic nervous system’s role in stress adaptation?
It regulates involuntary functions, with the sympathetic division activating during stress and the parasympathetic calming the body after.
What happens when compensatory mechanisms fail during stress?
The body can no longer maintain homeostasis, leading to illness, disability, or death.
How does the body compensate during hemorrhage?
increases heart rate, constricts blood vessels, and redirects blood flow to vital organs to maintain tissue oxygenation.
What are glucocorticoids, and how do they function in stress?
Hormones like cortisol that help the body respond to stress by increasing blood glucose and suppressing inflammation.
What are vasopressors, and how do they help in stress management?
Medications that constrict blood vessels, raising blood pressure to improve blood flow to vital organs during stress or injury.
What role does cortisol play in the stress response?
Cortisol increases blood glucose, regulates immune response, and helps the body manage prolonged stress.
What is the “fight or flight” response?
physiological reaction triggered by the sympathetic nervous system that prepares the body to face or escape danger.
What is the sympathetic nervous system?
division of the autonomic nervous system that activates the body’s “fight or flight” response during stress.
What is the parasympathetic nervous system?
division of the autonomic nervous system that promotes “rest and digest” functions after the stressor has passed.
