STRESS
Any circumstance that upsets our homeostasis/homeostatic balance; threatening event that has the potential to harm us or disturb our well-being in some way
What is stress
Two of the major systems that are activated when the body experiences a stressor
Sympathetic Nervous System activation (sympathetic-adreno-medullar system) and
Hypothalamic-Pituitary-Adrenal (HPA) Axis
In the sympathetic branch ______ is a major neurotransmitter between the post-ganglionic neurons and effector organs. Sympathetic fibers release this as their neurotransmitter
Norepinephrine
Many depressed individuals fail this test, meaning their blood cortisol levels do not decrease significantly after dexamethasone injection, indicating a malfunctioning feedback system.
Evidence that the normal inhibitory feedback of the HPA axis is disrupted in depression (dexamethasone suppression test)
A Component of the peripheral nervous system that regulates involuntary physiologic processes, including heart rate, blood pressure, respiration, digestion, and sexual arousal and contains the two distinct divisions of sympathetic and parasympathetic
Autonomic Nervous System (ANS)
Constant high sympathetic activation and persistently elevated cortisol levels, which produce damaging effects on various systems like
Immune system, cardiovascular system, and central nervous system (CNS) ~brain~
Chronic stress
In the parasympathetic branch _____ is a major neurotransmitter between the POST-ganglionic neurons and effector organs
ACh or Acetylcholine
Hippocampal volume decrease;
amygdala hyperactivity
Disrupted/impaired connectivity;
brain abnormalities that have been observed in depression
Our bodies evolved specific physiological mechanisms to respond to threatening stimuli only meant for acute situations and can be maladaptive when chronic
adaptive responses
Chronic stress has significant ___________, weakening the body's defense mechanisms. Consequences include, increased risk of developing infectious diseases (influenza, common cold), prolonged illness duration, increase rate of disease progression for conditions like HIV and tumor growth
*supported by animal and human studies*
Immunosuppressant effects
Genetics; variations in genes related to CRH, glucocorticoid receptors, 5-HT transporter, and COMT can influence stress thresholds. Social support can activate brain reward circuits and oxytocin release, can help reduce fear responses. Sufficient sleep helps dampen the amygdala's response to negative emotional stimuli. Good nutrition supports overall brain health and function. Mindfullness/meditation enhances prefrontal cortical functioning and cognitive control over emotions. Cognitive strategies like cognitive reappraisal, positive reframing and optimism improve coping mechanisms.
Describe genetic and environmental factors that influence resilience to stress and how they operate.
Part of the ANS division known as "fight or flight". Associated with arousal and activation leads to increased heart rate, blood pressure, oxygen uptake in lungs and release of glucose from liver to provide energy.
The primary role is to prepare body for activity by mobilizing energy resources to respond to threat.
Sympathetic System
Regulation of the hypothalamic-pituitary-adrenal (HPA) axis. Cortisol, the final product acts on the hypothalamus (inhibiting CRH) and pituitary gland (inhibiting ACTH) to decrease production when concentrations are high
Negative feedback loop
Chronic cortisol exposure can impair immune function= more infections. Increase cardiovascular risk=hypertension, heart disease.
Damaging effects of prolonged stress on the brain
Known as "rest and digest". Associated with relaxation; active during calm and relaxed states. Effects are opposite of the sympathetic system. Activation produces, decreased heart rate, blood pressure and includes the stimulation of reproductive function and other organs. Mediates activities that restore body's energy rather than mobilizing it.
Parasympathetic System
Increased heart rate and blood pressure deliver more oxygen to muscles. Increased respiration increases oxygen intake. Increase in glucose release increases energy for action. Dilation of pupils = hightened visual alertness. Redistribution of blood from gut to the muscles and brain. it raises alertness, releases energy stores, and increases inflammation to fight infections.
some of the immediate effects of activating these systems that are adaptive in helping the body respond to a threat.(SNS fight or flight)