Stress

Question 1

hypofunction of stress can lead to

Answer 1

boredom or depression

Question 2

hyperfunction of stress can lead to

Answer 2

anxiety or poor health

Question 3

what stimulates the fight/flight sympathetic NS?

Answer 3

the hypothalamus activates SNS (f/f response) by releasing epinephrine or norepinephrine

Question 4

what does the release of epinephrine/norepinephrine from hypothalamus trigger?

Answer 4

this stimulates the release of EP and NE from adrenal medulla which activates body cells, endocrine glands, then finally the brain

Question 5

how long does the f/f response last? what influences how long it lasts?

Answer 5

Dont last a long time. There is feedback through vegas nerve. This leads to rapid physiological adaptation (alertness, vigilance, appraisal, f or f) → rapid responses and short term effects

Question 6

how is threat communicated to the hypothalamus?

Answer 6

the medulla (the control center for SNS response) gets input from amygdala

Question 7

what are the two endocrine responses to stress? (structure and speed/effects)

Answer 7

medulla- releases adrenaline (epinephrine) to generate a fast response

cortex- releases glucocorticoids (cortisol) to generate a slower, longer-lasting response

Question 8

A stressor causes a long term stress response process to start. What happens in this process?

Answer 8

Hypothalamus secretes CRH (Corticotropin-releasing hormone) → anterior pituitary releases (in ~15 sec) ACTH signals to the cortex of the adrenal gland → ACTH stimulates cortisol release form adrenal cortex (in ~ a couple minutes). Cortisol (has metabolic effects and serves as negative feedback signal) activates body’s cells, endocrine glands, brain, etc. peak of cortisol release is at 10 min

Question 9

what is the CRH (Corticotropin-releasing hormone)

Answer 9

regulates the hypothalamic-pituitary-adrenal (HPA) axis (the main organizer of the body’s response to stress.

Question 10

where is CRH secreted from?

Answer 10

secreted from the hypothalamus

Question 11

what structure does CRH stimulate

Answer 11

stimulated the anterior pituitary to release adrenocorticotropic hormone (ACTH)

Question 12

what does ACTH target?

Answer 12

ACTH then acts on its target organ, the adrenal cortex.

Question 13

what are tropic hormones?

Answer 13

hormones that stimulate other endocrine glands so as to produce their particular hormones. They are produced and secreted by the anterior pituitary gland. They play a vital role in influencing the function, growth, and nutrition of other endocrine cells.

Question 14

what is a metabolic stress response and what does it help with/what are some examples?

Answer 14

Mobilize energy (to get moving): inhibits energy storage

• Inhibit insulin (blocks breakdown of triglycerides in fat tissue, promotes glucose uptake)
• Inhibit ovulation in females, reduces testosterone in males (reproductive stress response)
• Vasoconstriction, increase bp (cardiovascular stress response )
• Inhibit pain perception, immune system, tissue repair

Question 15

Short term stress response

Answer 15

• Glycogen broken down to glucose; increased blood glucose
• Increased bp
• Increased breathing rate
• Increased metabolic rate
• Change in blood flow patterns, leading to increased alertness and decreased digestive and kidney activity

Question 16

Long term stress response

Answer 16

Mineralocorticoids released from adrenal cortex
1. Retention of sodium ions and water by kidneys
2. Increased blood volume and bp

Glucocorticoids released from adrenal cortex
1. Proteins and fats broken down and converted to glucose, leading to increased blood glucose
2. Immune system may be suppressed

Question 17

Metabolic stress response

Answer 17

Mobilize energy (to get moving): inhibits energy storage
- Inhibit insulin (blocks breakdown of triglycerides in fat tissue, promotes glucose uptake)

• Inhibit ovulation in females, reduces testosterone in males (reproductive stress response)
• Vasoconstriction, increase bp (cardiovascular stress response)
• Inhibit pain perception, immune system, and tissue repair

Question 18

Hypothalamic pituitary adrenal axis (HPA)

How is the threat communicated to hypothalamus?

Answer 18

Afferent innervation of hypothalamus
Paraventricular nucleus (PVN) of hypothalamus input:
Amygdala:
Dorsal raphe nucleus:
Locus coeruleus:
Central gray
Circumventricular organ: bloodborne chemosensory input - important in negative feedback

Sympathetic: Physiological changes
HPA: Metabolic response

Question 19

Acute vs Chronic stress

Answer 19

Acute: seconds- hours
Hippocampus: neurologically- neurogenesis, behaviorally - improved memory
Ex: acute stress in rats (immobilization)
Acute response is some cortisol release. Stem cells in hippocampus make new neurons. You see this lead to improved mental performance two weeks later. Astrocytes mediate this effect of neurogenesis by releasing growth factors (FBF2) (structural change))

Chronic: hours - decades
Hippocampus: atrophy, behaviorally - impaired memory
Ex: rats immobilized
Chronic - excessive release of cortisol. Reduces neurotrophic factor release. Atrophy of hippocampal neurons (reduced survival and growth). Hippocampus is vulnerable to damage with stress but reversible

Question 20

Hippocampus critical in ending stress response (communicates with hypothalamus)

Answer 20

More cortisol secretion destructs hippocampal neurons leading to fewer hippocampal neurons which then decreases ability to shut off cortisol secretion

Question 21

Chronic amygdala

Answer 21

Expansion of neurons
Increase nerve excitability
- Risk of anxiety disorders

Question 22

What is chronic immobilization stress (CIS)? what are some findings about stress and its structural and behavioral effects?

Answer 22

a chronic stress model used to invoke stress in model animals and determine the effects

FOUND: Structural effects of amygdala - increased dendritic branches and increased dendritic spines

Accompanied by development of anxiety-like behavior on elevated plus- maze

Question 23

When does stress result in pathology?

Answer 23

Many factors interact
Timing, duration, individual variability (genetics)
Ex: individuals who felt they had little sense of purpose were more likely to die within a few years after diagnosis of heart disease

Overstimulation by same hormones that enable adaptation on short term basis
Outcome of stress response determined by intensity, length, frequency (acute vs chronic)
Chronic stress surpasses regulatory capacity of organisms can lead to maladaptive responses

Question 24

what were some of the effects in humans’ stress levels who were in an 8 week meditation intervention

Answer 24

stress reduction correlates with structural changes in the amygdala

Reduction in perceived stress rating
Decrease in right amygdala gray matter density