bio lecture 7 Flashcards
What is the stress response?
Combination of physiological processes in response to threats to survival
Involves the sympathetic nervous system and HPA axis
Who is defined the stress responce?
Hans Selye
His work laid the foundation for understanding stress in physiology
What role does the sympathetic nervous system (SNS) play during stress?
Speeds up processes such as heart rate, breathing rate, and sweating
Inhibits the parasympathetic nervous system
What neurotransmitter is used by post-ganglionic neurons of the SNS?
Noradrenaline
Acetylcholine is used by the parasympathetic nervous system
Which hormones are released during the stress response?
Adrenaline (epinephrine) and cortisol
Released by the adrenal gland
What does the adrenal medulla release?
Adrenaline and noradrenaline
Stimulated by the sympathetic nervous system
What triggers the release of cortisol?
ACTH (adrenocorticotrophic hormone) from the anterior pituitary gland
Triggered by CRH (corticotropin-releasing hormone) from the hypothalamus
What starts the stress response?
Activation of brain regions like the amygdala and sgACC
Amygdala activates both SNS and HPA axis
What is the role of the amygdala in stress response?
Activates SNS and HPA axis in response to challenges
Central nucleus responds to homeostatic challenges, while medial nucleus responds to psychogenic challenges
What is the function of the subgenual anterior cingulate cortex (sgACC)?
Indirectly activates stress response
Part of the anterior cingulate cortex
How does the body regulate the HPA axis after stress?
Cortisol inhibits further ACTH production, providing a negative feedback loop
Anterior hippocampus monitors cortisol levels to help regulate HPA axis
What is a major risk factor for Major Depressive Disorder (MDD)?
Chronic stress
Dysregulation of the HPA axis contributes to MDD
What are common symptoms of Major Depressive Disorder (MDD)?
Persistent low mood, fatigue, sleep/appetite issues, feelings of worthlessness
More common in women
What is the relationship between chronic stress and the HPA axis?
Chronic stress can lead to dysregulation and high cortisol levels
This can contribute to the development of MDD
What effect does REM sleep deprivation have?
Long-term effects on mood and mental health
Many antidepressants suppress REM sleep
What are SSRIs and how do they work?
Selective serotonin reuptake inhibitors that increase synaptic serotonin by blocking reuptake
Examples include Prozac and Cipramil
What is the mechanism of action for ketamine as an antidepressant?
NMDA receptor antagonist promoting new synapse formation
Rapid effects at sub-anesthetic doses but has risks
What are common treatments for anxiety disorders?
Therapy (CBT, exposure therapy) and medications (SSRIs, beta-blockers, benzodiazepines)
Anxiety disorders often co-occur with depression
What are benzodiazepines used for?
Fast-acting sedatives and anxiolytics
Enhance GABA-A receptor activity to increase inhibition
What are the short-term side effects of benzodiazepines?
Drowsiness, confusion, memory loss, muscle relaxation
Long-term use may increase dementia risk
How is chronic stress related to mood disorders?
Key risk factor contributing to their development
Involves dysregulation of the HPA axis
What is the legal status of ketamine?
Class B substance, illegal without a prescription
Used for its rapid antidepressant effects
