Anxiety and Stress Disorders (Lecture 11) Flashcards
1
Q
stressor
A
- anything that disrupts physiological balance
- psychological or physical
2
Q
stress response
A
-body’s adaptations designed to reestablish balance in homeostasis
3
Q
stress
A
-general state of stressors that provoke a stress response
4
Q
What triggers the stress response?
A
-perception of a stressor
5
Q
Stress response
A
- sympathetic nervous system response
- hypothalamic pituitary adrena (HPA) axis
- both systems send messages to the adrenal glands which release stress horomones into the bloodstream
6
Q
stress horomones (2)
A
- glucocoricoids
- epinephrine
7
Q
adrenal glands
A
-release stress hormones (glucocorticoids(cortisol)) and epinephrine (adrenaline)
8
Q
two physiological responses to stressors
A
- sympatheitc nervous system (ANS)
2. hypothalamic-pituitary-adrenal axis (HPA)
9
Q
Sympathetic nervous system
A
-epinephrine (adrenaline) from adrenal medulla
10
Q
hypothalamic-pituitary adrenal axis
A
- HPA
- on in minutes (more delayed release of hormones than ANS)
- releases glucocorticoids from adrenal cortex
11
Q
Stress Response 2 components
A
- autonomic nervous system (works in seconds) via hormones in bloodstream
- hypothalamus pituitary adrenal axis (HPA) (works in minutes) via neurotransmitters in synaptic gap
12
Q
ANS pathway
A
- body realizes it is in fight or slight
- stimulates epinephrine release from adrenal medulla (immediate but not long lasting energy used)
- parasympathetic activated in order to relax(this system stores energy)
13
Q
Adrenal medulla
A
releases epinephrine into circulation (activated sychronously with rest of synpathetic ANS
-epinephrine can not pass throught blood brain barrier
14
Q
No parasympathetic innervation in…….
A
adrenals
15
Q
Effects of epinephrine
A
- increase in O2 via increase in heart rate, respiration, etc
- increase in glucose in blood via breakdown of glycogen in liver
- does not cross blood brain barrier
- more energy for muscle contraction
- frees up long term stored energy into usable show term energy
- blood does not travel to irrelevant areas such as sexual organs or digestive tract
16
Q
No matter what the stressor
A
-the response is the same
17
Q
Hypothalamus Pituitary adrenal axis (HPA)
A
- slower onset of effects (minutes)
- leads to the 4 F’s (feeding fighting fleeing fornicating)
18
Q
hypothalamus
A
- makes up less than 1% of brain
- gets responses from mucles and intergrates them
- mediated feeding, flight or fight, sex
- first step in command system that deals with an imbalance in homeostasis
- direct connection to the pituitary via a blood portal system (to anterior pituitary) or neurons (posterior pituitary)
19
Q
What regulates many peripheral glands of the endocrine system? (not just the adrenals)
A
- hypothalamus
2. pituitary
20
Q
Anterior pituitary
A
-cell bodies in PVN of the hypothalamus send axons to hypothalamo-pituitary portal system
21
Q
posterior Pituitary
A
- activated directly
- releases oxytocin and vapopressin
- cell bodies in paraventicular nucleur (PVN of the hypothalamus send axons to the posterior pituitary
- axon terminals release hormones into blood vessels
22
Q
oxytocin
A
(released by posterior pituitary)
- labor
- lactation
- pair bonding
23
Q
vasopressin
A
(released by posterior pituitary)
- antidiuretic
- blood pressure
24
Q
portal system
A
veins that carry hormones to anterior pituitary
25
anterior pituitary cells
- respond to hormones and release other hormones in general circulation
- axons only go to top of portal system
- hormones take message from there
- tropic hormones
26
Normal Stress response (HPA axis)
-brain relizes stressor
-hypolalamus releases corticotropin releasing hormone
-goes into blood portal system to anterior pituitary
Adrenocoticotropic hormones does to adrenal cortex
-adrenal cortex releases cortisol which gives negative feedback
27
Epinephrine
works to provide short term energy resouces (glucose)
| -in the liver = breakdown of glycogen to glucose
28
glucocorticoids
- work to provide prolonged energy resources (glucose) from long term energy store to provide sustainable energy to prolonged stressors
- in liver = breakdown of protein and fatty acids into glucose (gluconeogenesis)
- in muscles = prtein breakdown into glucose (proteolysis)
- in adipose tissue (fat) = breakdown of fatty acids into glucose
29
glucocorticoids - cortisol
- baseline cortisol release has a circadian rhythn that peaks at waking
- cortisol is also relased during copulation, excursive, drug use
- glucorticoids are released when your metabolism needs a boost
30
brain regulation of sress response
- corticotropin releasing hormone (CRH) neurons of the PVN regulated by:
- the amygdala
- the hippocampus
31
regualtions of sress response in the amygdala
- basal lateral nuclei is the most important
- sensory information enters basolateral amygdala (BLA)
- BLA--> central mucleus of the amygdala (CeA)
- CeA---> hypothalamus ---> stress response
32
stimulation of amygdala in humans
- stress and fear
| - increase CRH release
33
regulation of stress response (hippocampus)
- hippocampus contain glucocorticoid receptors
- detects circulating cortisol and sends negative feedback to hypothalamus
- activation leas to decrease CRH release
34
hippocampus and chronic stress
-due to extended exposure to cortisol
-reduces dendritic arbors of hippocampul neurons
-chronic stress also reduces hippocampal cell numbers
-cell death
-reduced birth of new neurons (neurogenesis)
= reduced overall hippocampus size- degeneration starts a vicious sycle in which the stress response is less regulated which results in more corisol release and more hippocampal damage
35
hippocampus integral
- in learning ad memory
| - vietnam combat vetrans and civtims of child abuse = reduced hippocampal volume and short-term deficits
36
rats placed in present of cat for 75 minutes ---->
- infered animals ability to learn spatial task
- molecular mechanisms of learning impaired in hippocampus
- acute stress also impairs long term survival of NEW hippocampal neurons
37
Psychoneuroimmunology
study of the interactioins between the immune system and behavior (e.g. the stress response)
--immune system weakened/would heal slower in those who have chronic stress
38
cell mediated immunity
- antigen engulfed by macrophace
- t cell recognizes activated macrophage
- bound t cells proliferate and develop into a form that kills body cells that have been infected by the micoorganism
39
antibody mediated immunity
-foreign antigen are bound by B cells with appopriate receptor
40
Chonic stress diminishes immune response
- stops the maturation of lymphocytes (t cells and B cells)
| - destruction of lymphocytes
41
Reasoning for chronis stress diminishing immune response
- originally believed to conserve energy for the fight or flisht response
- in reality
42
acute stress (5-100 minutes)
-actually enhances many elements of the immune response
-increase in number of lymphocytes in peripheral blood
increase in amount of antibodies in saliva
43
glucocoticoids depress immune response by....
-released during prolonged stress are imunnosupressive to regulate
44
chronic stress
-maintenance of high glucocorticoid levels during chronic stress prolongs suppression of immune system and results in below baseline immunity
45
acute v chronic stress
- acute stress improves performance
| - persisting stress can make us more susceptible to things because it weakens the immune system
46
Anxiety disorders
-characterized by inappropriate (pathological) expression of fear
-15 percent of american will suffer from one this year
-most connon of psychiatric disorders
-GAD, SAD
-OCS
PTSD
47
Panic disorder
- episodic attacks of acute anxiety causing unremitting terror (panic attacks)
- 2% of population
- 2x more women
48
Generalized Anxiety order (GAD)
- excessive worry and anxiety for at least 6 months that prevents living "full" life
- 3% of population
- 2x more women
49
social anxiety order (SAD)
- excessive fear of being exposed to the scrutiny of others
- leads to pathological avoidance
- 5% of population
- equal in women and men
50
Panic DIsorder, GAD, SAD trends
- some heredity aspect (most likely to have one if parent has it)
- temporal lobe abnormalities in 40% patients with panic disorder
- over activation of amygdala----> releases excessive amount of cortisol
51
Panic DIsorder, GAD, SAD treatment
- Benzodiazpines
| - SSRIs
52
Benzodiazpines
- bind to GABAa receptor, opening Cl- channel, causing neuronal inhibition
- high density of GABAa receptors in amygdala
- downside: highly addictive, can lead to symptoms that you were originally trying to treat
- withdrawal = increased anxiety
53
SSRIs
- anxiolytic effects NOT immediate-it takes weeks
| - SSRIs do increase glucocorticoid receptors in hippocampus --> enhanced negative feedback from cortisol
54
OCD characteristics
- characterized by uncontrollable thoughts (obsessions) and/or the need to perform specific acts repeatedly (compulsions)
- 1-2% of population
- slightly more prevalent in females
55
OCD circuit in brain
orbitofrontal cortex (OFC) --> basal ganglia --> thalamus --> back to OFC
56
OFC=
- orbitofrontal cortex
| - recognizes situations that have personal significance and sends "worry" message to thalamus to regulate behavior
57
basal ganglia role in OCD circuit
- basal ganglia works as a "brake" suppressing original "worry" signal sent by OFC
- damage to basal ganglia may impair its ability to stop the OFC from sending continual messages= obsessions which then commend the thalamus to initiate actions= compulsions
